From DENG0035 at ntu.edu.sg Wed Apr 1 21:03:12 2009 From: DENG0035 at ntu.edu.sg (#DENG XIAO FANG (DENG0035)#) Date: Thu, 2 Apr 2009 12:03:12 +0800 Subject: [SAC-HELP] about reading the data Message-ID: <4BE7E7793288974D8EAFADCAB4A4685102E12279@MAIL22.student.main.ntu.edu.sg> Hello, Mr/Miss I have download the SAC ASCII data from IRIS, but there is no header file contained. So I find it difficult to understand the meaning of the data. The attach file is just one SAC ASCII file. I hope you can help me with the interpretation of the data. Thanks very much! Regards and Best Wishes! xiaofang -------------- next part -------------- An HTML attachment was scrubbed... URL: -------------- next part -------------- A non-text attachment was scrubbed... Name: 2007.255.11.03.51.0695.MY.KOM..LHZ.R.SAC_ASC Type: application/octet-stream Size: 12753 bytes Desc: 2007.255.11.03.51.0695.MY.KOM..LHZ.R.SAC_ASC URL: From maia153 at yahoo.com.ar Fri Apr 3 07:14:47 2009 From: maia153 at yahoo.com.ar (=?iso-8859-1?Q?MAR=CDALAURA_ROSA?=) Date: Fri, 3 Apr 2009 07:14:47 -0700 (PDT) Subject: [SAC-HELP] (no subject) Message-ID: <889582.69672.qm@web38806.mail.mud.yahoo.com> Dear Sac user's, I use SAC to analyze the seismogram, but when I use the sgftops conversion utility to convert the sgf file to ps file, it says that it cannot execute binary file. I have found some examples on internet, where the command "sgftops" can be used directly in SAC. SAC> r file.sac SAC> bd sgf SAC> p SAC> sgftops f001.sgf figure.ps sh:/usr/local/sac/bin/sgftops: cannot execute binary file Can you give me some advices? Thank you so much. Waiting to hearing from you. Mar?a Yahoo! Cocina Recetas pr?cticas y comida saludable http://ar.mujer.yahoo.com/cocina/ From Onur.Tan at mam.gov.tr Fri Apr 3 07:30:58 2009 From: Onur.Tan at mam.gov.tr (Onur Tan) Date: Fri, 3 Apr 2009 17:30:58 +0300 Subject: [SAC-HELP] (no subject) In-Reply-To: <889582.69672.qm@web38806.mail.mud.yahoo.com> Message-ID: <9E88105FE4AC8C47BD6D00EB9831482F29DAC23C@posta.mam.gov.tr> Dear Maria, Does your operating system agree with the sac-binary files? if it does, check the executable flag of the sgftops. You see someting like this -rwxr-xr-x 1 seismo seismo 17K May 20 2008 /usr/local/sac/bin//sgftops ^ ^ ^ if there is no "x" flag use: chmod +x /usr/local/sac/bin/sgftops and re-run the program. onur Dr. Onur TAN |------------------------------------------------------------ ------------- | | T?B?TAK Marmara Ara?t?rma Merkezi | TUBITAK Marmara Research Center | | Yer ve Deniz Bilimleri Enstit?s? | Earth and Marine Sciences Institute | | Gebze - Kocaeli | Gebze - Kocaeli - TURKEY | -------------------------------------------------------------------------- -----Original Message----- From: sac-help-bounces at iris.washington.edu [mailto:sac-help-bounces at iris.washington.edu] On Behalf Of MAR?ALAURA ROSA Sent: Friday, April 03, 2009 5:15 PM To: sac-help at iris.washington.edu Subject: [SAC-HELP] (no subject) Dear Sac user's, I use SAC to analyze the seismogram, but when I use the sgftops conversion utility to convert the sgf file to ps file, it says that it cannot execute binary file. I have found some examples on internet, where the command "sgftops" can be used directly in SAC. SAC> r file.sac SAC> bd sgf SAC> p SAC> sgftops f001.sgf figure.ps sh:/usr/local/sac/bin/sgftops: cannot execute binary file Can you give me some advices? Thank you so much. Waiting to hearing from you. Mar?a Yahoo! Cocina Recetas pr?cticas y comida saludable http://ar.mujer.yahoo.com/cocina/ _______________________________________________ sac-help mailing list sac-help at iris.washington.edu http://www.iris.washington.edu/mailman/listinfo/sac-help From Onur.Tan at mam.gov.tr Fri Apr 3 07:34:46 2009 From: Onur.Tan at mam.gov.tr (Onur Tan) Date: Fri, 3 Apr 2009 17:34:46 +0300 Subject: [SAC-HELP] about reading the data In-Reply-To: <4BE7E7793288974D8EAFADCAB4A4685102E12279@MAIL22.student.main.ntu.edu.sg> Message-ID: <9E88105FE4AC8C47BD6D00EB9831482F29DAC23D@posta.mam.gov.tr> Dear xiaofang you can find all information in User's Manual page in the following site http://www.iris.edu/manuals/sac/manual.html look at SAC Data File Format (Part 1 and 2) bye onur Dr. Onur TAN |------------------------------------------------------------ ------------- | | T?B?TAK Marmara Ara?t?rma Merkezi | TUBITAK Marmara Research Center | | Yer ve Deniz Bilimleri Enstit?s? | Earth and Marine Sciences Institute | | Gebze - Kocaeli | Gebze - Kocaeli - TURKEY | -------------------------------------------------------------------------- ________________________________ From: sac-help-bounces at iris.washington.edu [mailto:sac-help-bounces at iris.washington.edu] On Behalf Of #DENG XIAO FANG (DENG0035)# Sent: Thursday, April 02, 2009 7:03 AM To: sac-help at iris.washington.edu Subject: [SAC-HELP] about reading the data Hello, Mr/Miss I have download the SAC ASCII data from IRIS, but there is no header file contained. So I find it difficult to understand the meaning of the data. The attach file is just one SAC ASCII file. I hope you can help me with the interpretation of the data. Thanks very much! Regards and Best Wishes! xiaofang -------------- next part -------------- An HTML attachment was scrubbed... URL: From mayenew at gmail.com Wed Apr 8 15:50:56 2009 From: mayenew at gmail.com (Melaku Ayenew) Date: Wed, 8 Apr 2009 16:50:56 -0600 Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response Message-ID: Hi All, I am trying to remove instrument responses from STS_2, CMG3T. CMG_ES broadband instruments. I got the poles and zeros from IRIS Pascal Instrumentation. But I have difficulty figuring out what constant I should use in the *.pz file that has to read by the SAC TRANSFER command. For example, I was trying to synthesis a WA seismogram by removing the STS_2 response and convoulating the WA response. I used a constant of 1 in this calcultion. The synthesis seismogrm looks good but the displacemnt values don't make sense (they are several hunderd meters). I understand it is because of the CONSTANT=1 I put. My Question is How can I calculate the correct CONSTANT that I need to put with the zeros and poles in the SAC *.pz file. The IRIS PASCAL instrumentation page gives the zeros and poles and a normalization factor. I greatly appreciate your help in this matter. Melaku Bogale New Mexico State University Department of Physics Las Cruces NM 88003-8001 -------------- next part -------------- An HTML attachment was scrubbed... URL: From chad at iris.washington.edu Wed Apr 8 21:13:57 2009 From: chad at iris.washington.edu (Chad Trabant) Date: Wed, 8 Apr 2009 21:13:57 -0700 Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response In-Reply-To: References: Message-ID: Hello Melaku Bogale, You need to know the total sensitivity of the digitizer, this is the value which relates digital counts to ground units. The poles and zeros only represent the sensor. The CONSTANT in the SAC poles and zeros file should be the total sensitivity multiplied by the normalization factor for the poles and zeroes. The value for CONSTANT depends on the units desired also. Chad IRIS DMC On Apr 8, 2009, at 3:50 PM, Melaku Ayenew wrote: > Hi All, > I am trying to remove instrument responses from STS_2, CMG3T. CMG_ES > broadband instruments. I got the poles and zeros from IRIS Pascal > Instrumentation. But I have difficulty figuring out what constant I > should use in the *.pz file that has to read by the SAC TRANSFER > command. For example, I was trying to synthesis a WA seismogram by > removing the STS_2 response and convoulating the WA response. I used > a constant of 1 in this calcultion. The synthesis seismogrm looks > good but the displacemnt values don't make sense (they are several > hunderd meters). I understand it is because of the CONSTANT=1 I put. > My Question is How can I calculate the correct CONSTANT that I need > to put with the zeros and poles in the SAC *.pz file. The IRIS > PASCAL instrumentation page gives the zeros and poles and a > normalization factor. > I greatly appreciate your help in this matter. > > Melaku Bogale > New Mexico State University > Department of Physics > Las Cruces NM 88003-8001 > _______________________________________________ > sac-help mailing list > sac-help at iris.washington.edu > http://www.iris.washington.edu/mailman/listinfo/sac-help From chad at iris.washington.edu Thu Apr 9 16:28:34 2009 From: chad at iris.washington.edu (Chad) Date: Thu, 9 Apr 2009 16:28:34 -0700 Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response In-Reply-To: References: Message-ID: <3E2812AA-9856-4031-AE0F-B9F64BB74FAB@iris.washington.edu> Hello Melaku, I am forwarding this to the sac-help list in the hopes that it may garner the attention of more expertise. Your calculation of CONSTANT looks generally correct with the exception of the 2*pi, it should not be included. A standard gain STS-2 should be nominally 1500 Volts/meters/second, which needs to be scaled if you want nanometers. I have no idea what the digitizer gain for a RefTek 130 is, but lets assume your number is correct for now. CONSTANT = A0 * SensorGain * Digitizer Gain CONSTANT = 5.92e+07 * 1500 / 1.589e-06 = 5.588e+16 (so it looks like 2*pi is not in there after all). That CONSTANT results in units of meters. So scale it by a factor of 1e9 for nanometers = 5.588e25 Hopefully someone more knowledgeable will correct any mistakes I've made. On a slight related note, the poles and zeros you are using are the "truncated"/"simplified" STS-2 response and not the STS-2 nominal responses (you can access the nominal responses for each of 3 generations of STS-2 here: http://www.iris.edu/NRL/sensors/streckeisen/streckeisen_sts2_sensors.html) . This is not a critical problem unless you are working with high frequency data, I have heard that it's not important below 35 Hz. Chad On Apr 9, 2009, at 3:11 PM, Melaku Ayenew wrote: > Hello Chad, > Thank you for your response > I am just starting to learn sac for my research, I was trying to > remove STS-2 broadband instrument and convolute the Wood-Anderson > response. This is the STS2.pz file I came up with would you check it > for me please > > ZEROS 2 (rad/sec) > 0.000 0.000 > 0.000 0.000 > > POLES 5 (rad/sec) > > -0.03701 0.03701 > -0.03701 -0.03701 > -251.3 0.0000 > -131.0 467.30 > -131.0 -467.30 > > CONSTANT 5.5884E+16 > > This is how I calculate the the Constant > CONSTANT=A0 X SensorGain X Digitizer Gain X 2*pi > Where A0 is normalization factor =5.92 E+07 > The digitizer is REF TEC 130 data logger with bit weight > 1.589E-06volts which I figure the digitizer gain would be 1/1.589 > E-06 ( I am not sure about this step) > > And from SAC>transfer from polezero subtype STS2.pz to WA > > when I plot this I got a waveform with amplitude in the order of > 10E-4 nm (transfer returns values in nm) > > I really appreciate your help. > Thank you in advance.!! > > > > Melaku Bogale > New Mexico State University > Department of Physics > Las Cruces NM 88003-8001 > > > > > On Wed, Apr 8, 2009 at 10:13 PM, Chad Trabant > wrote: > > Hello Melaku Bogale, > > You need to know the total sensitivity of the digitizer, this is the > value which relates digital counts to ground units. The poles and > zeros only represent the sensor. The CONSTANT in the SAC poles and > zeros file should be the total sensitivity multiplied by the > normalization factor for the poles and zeroes. The value for > CONSTANT depends on the units desired also. > > Chad > IRIS DMC > > > On Apr 8, 2009, at 3:50 PM, Melaku Ayenew wrote: > > Hi All, > I am trying to remove instrument responses from STS_2, CMG3T. CMG_ES > broadband instruments. I got the poles and zeros from IRIS Pascal > Instrumentation. But I have difficulty figuring out what constant I > should use in the *.pz file that has to read by the SAC TRANSFER > command. For example, I was trying to synthesis a WA seismogram by > removing the STS_2 response and convoulating the WA response. I used > a constant of 1 in this calcultion. The synthesis seismogrm looks > good but the displacemnt values don't make sense (they are several > hunderd meters). I understand it is because of the CONSTANT=1 I put. > My Question is How can I calculate the correct CONSTANT that I need > to put with the zeros and poles in the SAC *.pz file. The IRIS > PASCAL instrumentation page gives the zeros and poles and a > normalization factor. > I greatly appreciate your help in this matter. > > Melaku Bogale > New Mexico State University > Department of Physics > Las Cruces NM 88003-8001 > _______________________________________________ > sac-help mailing list > sac-help at iris.washington.edu > http://www.iris.washington.edu/mailman/listinfo/sac-help > > -------------- next part -------------- An HTML attachment was scrubbed... URL: From chad at iris.washington.edu Thu Apr 9 19:19:00 2009 From: chad at iris.washington.edu (Chad Trabant) Date: Thu, 9 Apr 2009 19:19:00 -0700 Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response In-Reply-To: References: <3E2812AA-9856-4031-AE0F-B9F64BB74FAB@iris.washington.edu> Message-ID: <67316042-A3CE-45A4-90BB-485FA0029B36@iris.washington.edu> Melaku, I can't help you verify the RefTek gain value. If the equipment is from the IRIS PASSCAL Instrument Center perhaps you can ask them for more details of the digitizer. If the data was processed by PASSCAL you might also have the data in SEED format in which case you can use the rdseed program to create the SAC poles and zeroes file for you. If you have a manual or any documentation for the digitizer it might be in there as well. Chad On Apr 9, 2009, at 5:46 PM, Melaku Ayenew wrote: > Hi Chad, > Thank you so much! It help me a lot! > One thing I am not sure about is the digitizer gain, I got this > value from IRIS, PASCAL, High Resolution Acquisition systems, under > Reftek R130 , 24 bit, 3 channel digitizer bit weight 1.589e-6 volts > @ X1 > gain. > > Thank you once again. > > Melaku > > On Thu, Apr 9, 2009 at 5:28 PM, Chad wrote: > > Hello Melaku, > > I am forwarding this to the sac-help list in the hopes that it may > garner the attention of more expertise. > > Your calculation of CONSTANT looks generally correct with the > exception of the 2*pi, it should not be included. > > A standard gain STS-2 should be nominally 1500 Volts/meters/second, > which needs to be scaled if you want nanometers. I have no idea > what the digitizer gain for a RefTek 130 is, but lets assume your > number is correct for now. > > CONSTANT = A0 * SensorGain * Digitizer Gain > > CONSTANT = 5.92e+07 * 1500 / 1.589e-06 = 5.588e+16 (so it looks like > 2*pi is not in there after all). > > That CONSTANT results in units of meters. So scale it by a factor > of 1e9 for nanometers = 5.588e25 > > Hopefully someone more knowledgeable will correct any mistakes I've > made. > > On a slight related note, the poles and zeros you are using are the > "truncated"/"simplified" STS-2 response and not the STS-2 nominal > responses (you can access the nominal responses for each of 3 > generations of STS-2 here: http://www.iris.edu/NRL/sensors/streckeisen/streckeisen_sts2_sensors.html) > . This is not a critical problem unless you are working with high > frequency data, I have heard that it's not important below 35 Hz. > > Chad > > On Apr 9, 2009, at 3:11 PM, Melaku Ayenew wrote: > >> Hello Chad, >> Thank you for your response >> I am just starting to learn sac for my research, I was trying to >> remove STS-2 broadband instrument and convolute the Wood-Anderson >> response. This is the STS2.pz file I came up with would you check >> it for me please >> >> ZEROS 2 (rad/sec) >> 0.000 0.000 >> 0.000 0.000 >> >> POLES 5 (rad/sec) >> >> -0.03701 0.03701 >> -0.03701 -0.03701 >> -251.3 0.0000 >> -131.0 467.30 >> -131.0 -467.30 >> >> CONSTANT 5.5884E+16 >> >> This is how I calculate the the Constant >> CONSTANT=A0 X SensorGain X Digitizer Gain X 2*pi >> Where A0 is normalization factor =5.92 E+07 >> The digitizer is REF TEC 130 data logger with bit weight >> 1.589E-06volts which I figure the digitizer gain would be 1/1.589 >> E-06 ( I am not sure about this step) >> >> And from SAC>transfer from polezero subtype STS2.pz to WA >> >> when I plot this I got a waveform with amplitude in the order of >> 10E-4 nm (transfer returns values in nm) >> >> I really appreciate your help. >> Thank you in advance.!! >> >> >> >> Melaku Bogale >> New Mexico State University >> Department of Physics >> Las Cruces NM 88003-8001 >> >> >> >> >> On Wed, Apr 8, 2009 at 10:13 PM, Chad Trabant > > wrote: >> >> Hello Melaku Bogale, >> >> You need to know the total sensitivity of the digitizer, this is >> the value which relates digital counts to ground units. The poles >> and zeros only represent the sensor. The CONSTANT in the SAC poles >> and zeros file should be the total sensitivity multiplied by the >> normalization factor for the poles and zeroes. The value for >> CONSTANT depends on the units desired also. >> >> Chad >> IRIS DMC >> >> >> On Apr 8, 2009, at 3:50 PM, Melaku Ayenew wrote: >> >> Hi All, >> I am trying to remove instrument responses from STS_2, CMG3T. >> CMG_ES broadband instruments. I got the poles and zeros from IRIS >> Pascal Instrumentation. But I have difficulty figuring out what >> constant I should use in the *.pz file that has to read by the SAC >> TRANSFER command. For example, I was trying to synthesis a WA >> seismogram by removing the STS_2 response and convoulating the WA >> response. I used a constant of 1 in this calcultion. The synthesis >> seismogrm looks good but the displacemnt values don't make sense >> (they are several hunderd meters). I understand it is because of >> the CONSTANT=1 I put. My Question is How can I calculate the >> correct CONSTANT that I need to put with the zeros and poles in the >> SAC *.pz file. The IRIS PASCAL instrumentation page gives the zeros >> and poles and a normalization factor. >> I greatly appreciate your help in this matter. >> >> Melaku Bogale >> New Mexico State University >> Department of Physics >> Las Cruces NM 88003-8001 >> _______________________________________________ >> sac-help mailing list >> sac-help at iris.washington.edu >> http://www.iris.washington.edu/mailman/listinfo/sac-help >> >> > > -------------- next part -------------- An HTML attachment was scrubbed... URL: From atawon at yahoo.com Sun Apr 12 01:49:06 2009 From: atawon at yahoo.com (Atalay Ayele) Date: Sun, 12 Apr 2009 01:49:06 -0700 (PDT) Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response Message-ID: <453146.59552.qm@web33206.mail.mud.yahoo.com> Selam Melaku, If you got the zeroes and poles files from IRIS/PASSCAL, you should be able to get the constants as well. once you removed responses from other instruments you can run: Trans from none to wa if you want to simulate WA instrument record. Good luck, Atalay --- On Thu, 4/9/09, Melaku Ayenew wrote: > From: Melaku Ayenew > Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response > To: sac-help at iris.washington.edu > Date: Thursday, April 9, 2009, 2:50 AM > Hi All, > I am trying to remove instrument responses from STS_2, > CMG3T. CMG_ES broadband instruments. I got the poles and > zeros from IRIS Pascal Instrumentation. But I have > difficulty figuring out what constant I should use in the > *.pz file that has to read by the SAC TRANSFER command. For > example, I was trying to synthesis a WA seismogram by > removing the STS_2 response and convoulating the WA > response. I used a constant of 1 in this calcultion. The > synthesis seismogrm looks good but the displacemnt values > don't make sense (they are several hunderd meters). I > understand it is because of the CONSTANT=1 I put. My > Question is How can I calculate the correct CONSTANT that I > need to put with the zeros and poles in the SAC *.pz file. > The IRIS PASCAL instrumentation page gives the zeros and > poles and a normalization factor. > > I greatly appreciate your help in this matter. > > Melaku Bogale > New Mexico State University > Department of Physics > Las Cruces NM 88003-8001 > > > -----Inline Attachment Follows----- > > _______________________________________________ > sac-help mailing list > sac-help at iris.washington.edu > http://www.iris.washington.edu/mailman/listinfo/sac-help > From Onur.Tan at mam.gov.tr Sun Apr 12 07:07:38 2009 From: Onur.Tan at mam.gov.tr (Onur Tan) Date: Sun, 12 Apr 2009 17:07:38 +0300 Subject: [SAC-HELP] YNT: Calculating the CONSTANT to use to remove instument response In-Reply-To: <453146.59552.qm@web33206.mail.mud.yahoo.com> References: <453146.59552.qm@web33206.mail.mud.yahoo.com> Message-ID: <9E88105FE4AC8C47BD6D00EB9831482F2ABFE3D2@posta.mam.gov.tr> Hi, SAC PZ constant must be recalculated from the A0 value of seismometer. SAC PZ file is in radyan, not Hz as in Guralp calib. documents. you can also look this message: http://www.iris.washington.edu/pipermail/sac-help/2009-February/000492.html best regards, Dr. Onur TAN ---------------------------------------------- 40.7866N 29.4500E --------- T?B?TAK Marmara Ara?t?rma Merkezi, Yer ve Deniz Bilimleri Enstit?s? TUBITAK Marmara Research Center, Earth and Marine Sciences Institute Gebze - Kocaeli - TURKEY ________________________________________ Kimden: sac-help-bounces at iris.washington.edu [sac-help-bounces at iris.washington.edu], Atalay Ayele [atawon at yahoo.com] Ad?na Tarih: 12 Nisan 2009 Pazar 11:49 Kime: sac-help at iris.washington.edu; Melaku Ayenew Konu: Re: [SAC-HELP] Calculating the CONSTANT to use to remove instument response Selam Melaku, If you got the zeroes and poles files from IRIS/PASSCAL, you should be able to get the constants as well. once you removed responses from other instruments you can run: Trans from none to wa if you want to simulate WA instrument record. Good luck, Atalay --- On Thu, 4/9/09, Melaku Ayenew wrote: > From: Melaku Ayenew > Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response > To: sac-help at iris.washington.edu > Date: Thursday, April 9, 2009, 2:50 AM > Hi All, > I am trying to remove instrument responses from STS_2, > CMG3T. CMG_ES broadband instruments. I got the poles and > zeros from IRIS Pascal Instrumentation. But I have > difficulty figuring out what constant I should use in the > *.pz file that has to read by the SAC TRANSFER command. For > example, I was trying to synthesis a WA seismogram by > removing the STS_2 response and convoulating the WA > response. I used a constant of 1 in this calcultion. The > synthesis seismogrm looks good but the displacemnt values > don't make sense (they are several hunderd meters). I > understand it is because of the CONSTANT=1 I put. My > Question is How can I calculate the correct CONSTANT that I > need to put with the zeros and poles in the SAC *.pz file. > The IRIS PASCAL instrumentation page gives the zeros and > poles and a normalization factor. > > I greatly appreciate your help in this matter. > > Melaku Bogale > New Mexico State University > Department of Physics > Las Cruces NM 88003-8001 > > > -----Inline Attachment Follows----- > > _______________________________________________ > sac-help mailing list > sac-help at iris.washington.edu > http://www.iris.washington.edu/mailman/listinfo/sac-help > _______________________________________________ sac-help mailing list sac-help at iris.washington.edu http://www.iris.washington.edu/mailman/listinfo/sac-help From Onur.Tan at mam.gov.tr Sun Apr 12 23:17:58 2009 From: Onur.Tan at mam.gov.tr (Onur Tan) Date: Mon, 13 Apr 2009 09:17:58 +0300 Subject: [SAC-HELP] Calculating the CONSTANT to use to remove instument response In-Reply-To: <67316042-A3CE-45A4-90BB-485FA0029B36@iris.washington.edu> Message-ID: <9E88105FE4AC8C47BD6D00EB9831482F2B17AF28@posta.mam.gov.tr> Hello, Reftek 130 has 24 bit digitizer. and the min and max count values are +-2^(24-1) = 6291456 count for +- 20V 20/(2*6291456) = 1.5895microVolt/count. We use ref2segy and seg2sac programs to convert the files. segy2sac (without -g parameter) removes the Reftek gain and its output is in Volts. best regars Onur Dr. Onur TAN |------------------------------------------------------------ ------------- | | T?B?TAK Marmara Ara?t?rma Merkezi | TUBITAK Marmara Research Center | | Yer ve Deniz Bilimleri Enstit?s? | Earth and Marine Sciences Institute | | Gebze - Kocaeli | Gebze - Kocaeli - TURKEY | -------------------------------------------------------------------------- ________________________________ From: sac-help-bounces at iris.washington.edu [mailto:sac-help-bounces at iris.washington.edu] On Behalf Of Chad Trabant Sent: Friday, April 10, 2009 5:19 AM To: sac-help at iris.washington.edu Subject: Re: [SAC-HELP] Calculating the CONSTANT to use to remove instument response Melaku, I can't help you verify the RefTek gain value. If the equipment is from the IRIS PASSCAL Instrument Center perhaps you can ask them for more details of the digitizer. If the data was processed by PASSCAL you might also have the data in SEED format in which case you can use the rdseed program to create the SAC poles and zeroes file for you. If you have a manual or any documentation for the digitizer it might be in there as well. Chad On Apr 9, 2009, at 5:46 PM, Melaku Ayenew wrote: Hi Chad, Thank you so much! It help me a lot! One thing I am not sure about is the digitizer gain, I got this value from IRIS, PASCAL, High Resolution Acquisition systems, under Reftek R130 , 24 bit, 3 channel digitizer bit weight 1.589e-6 volts @ X1 gain. Thank you once again. Melaku On Thu, Apr 9, 2009 at 5:28 PM, Chad > wrote: Hello Melaku, I am forwarding this to the sac-help list in the hopes that it may garner the attention of more expertise. Your calculation of CONSTANT looks generally correct with the exception of the 2*pi, it should not be included. A standard gain STS-2 should be nominally 1500 Volts/meters/second, which needs to be scaled if you want nanometers. I have no idea what the digitizer gain for a RefTek 130 is, but lets assume your number is correct for now. CONSTANT = A0 * SensorGain * Digitizer Gain CONSTANT = 5.92e+07 * 1500 / 1.589e-06 = 5.588e+16 (so it looks like 2*pi is not in there after all). That CONSTANT results in units of meters. So scale it by a factor of 1e9 for nanometers = 5.588e25 Hopefully someone more knowledgeable will correct any mistakes I've made. On a slight related note, the poles and zeros you are using are the "truncated"/"simplified" STS-2 response and not the STS-2 nominal responses (you can access the nominal responses for each of 3 generations of STS-2 here: http://www.iris.edu/NRL/sensors/streckeisen/streckeisen_sts2_sensors.html). This is not a critical problem unless you are working with high frequency data, I have heard that it's not important below 35 Hz. Chad On Apr 9, 2009, at 3:11 PM, Melaku Ayenew wrote: Hello Chad, Thank you for your response I am just starting to learn sac for my research, I was trying to remove STS-2 broadband instrument and convolute the Wood-Anderson response. This is the STS2.pz file I came up with would you check it for me please ZEROS 2 (rad/sec) 0.000 0.000 0.000 0.000 POLES 5 (rad/sec) -0.03701 0.03701 -0.03701 -0.03701 -251.3 0.0000 -131.0 467.30 -131.0 -467.30 CONSTANT 5.5884E+16 This is how I calculate the the Constant CONSTANT=A0 X SensorGain X Digitizer Gain X 2*pi Where A0 is normalization factor =5.92 E+07 The digitizer is REF TEC 130 data logger with bit weight 1.589E-06volts which I figure the digitizer gain would be 1/1.589 E-06 ( I am not sure about this step) And from SAC>transfer from polezero subtype STS2.pz to WA when I plot this I got a waveform with amplitude in the order of 10E-4 nm (transfer returns values in nm) I really appreciate your help. Thank you in advance.!! Melaku Bogale New Mexico State University Department of Physics Las Cruces NM 88003-8001 On Wed, Apr 8, 2009 at 10:13 PM, Chad Trabant > wrote: Hello Melaku Bogale, You need to know the total sensitivity of the digitizer, this is the value which relates digital counts to ground units. The poles and zeros only represent the sensor. The CONSTANT in the SAC poles and zeros file should be the total sensitivity multiplied by the normalization factor for the poles and zeroes. The value for CONSTANT depends on the units desired also. Chad IRIS DMC On Apr 8, 2009, at 3:50 PM, Melaku Ayenew wrote: Hi All, I am trying to remove instrument responses from STS_2, CMG3T. CMG_ES broadband instruments. I got the poles and zeros from IRIS Pascal Instrumentation. But I have difficulty figuring out what constant I should use in the *.pz file that has to read by the SAC TRANSFER command. For example, I was trying to synthesis a WA seismogram by removing the STS_2 response and convoulating the WA response. I used a constant of 1 in this calcultion. The synthesis seismogrm looks good but the displacemnt values don't make sense (they are several hunderd meters). I understand it is because of the CONSTANT=1 I put. My Question is How can I calculate the correct CONSTANT that I need to put with the zeros and poles in the SAC *.pz file. The IRIS PASCAL instrumentation page gives the zeros and poles and a normalization factor. I greatly appreciate your help in this matter. Melaku Bogale New Mexico State University Department of Physics Las Cruces NM 88003-8001 _______________________________________________ sac-help mailing list sac-help at iris.washington.edu http://www.iris.washington.edu/mailman/listinfo/sac-help -------------- next part -------------- An HTML attachment was scrubbed... URL: From limm001 at yahoo.com.cn Mon Apr 13 23:20:58 2009 From: limm001 at yahoo.com.cn (limm001 at yahoo.com.cn) Date: Tue, 14 Apr 2009 14:20:58 +0800 (CST) Subject: [SAC-HELP] Remove the response Message-ID: <690403.35322.qm@web15804.mail.cnb.yahoo.com> Hello,Mr./Miss I am trying to remove the response from the SAC data, and I want to know what is the units of "POLES" in the response-file. Thank you very much! ___________________________________________________________ ????????????????? http://card.mail.cn.yahoo.com/ -------------- next part -------------- An HTML attachment was scrubbed... URL: From Onur.Tan at mam.gov.tr Wed Apr 15 23:35:36 2009 From: Onur.Tan at mam.gov.tr (Onur Tan) Date: Thu, 16 Apr 2009 09:35:36 +0300 Subject: [SAC-HELP] Remove the response In-Reply-To: <690403.35322.qm@web15804.mail.cnb.yahoo.com> Message-ID: <9E88105FE4AC8C47BD6D00EB9831482F2B17B5D7@posta.mam.gov.tr> Hi, All poles-zeros are in radians (w=2*pi*f). and you must calculate CONSTANT using sensor and digitizer gains and sensor multiplier (A0). A0 must be in radians also. if you add +1 zero for displacement response A0 must be in displacement also. best regards Onur ________________________________ From: sac-help-bounces at iris.washington.edu [mailto:sac-help-bounces at iris.washington.edu] On Behalf Of limm001 at yahoo.com.cn Sent: Tuesday, April 14, 2009 9:21 AM To: sac-help at iris.washington.edu Subject: [SAC-HELP] Remove the response Hello,Mr./Miss I am trying to remove the response from the SAC data, and I want to know what is the units of "POLES" in the response-file. Thank you very much! ________________________________ ????????????????? -------------- next part -------------- An HTML attachment was scrubbed... URL: From =?UTF-8?Q?Shahar_Kadmiel_=D7=A9=D7=97=D7=A8_=D7=A7=D7=93=D7=9E?= Tue Apr 21 02:25:42 2009 From: =?UTF-8?Q?Shahar_Kadmiel_=D7=A9=D7=97=D7=A8_=D7=A7=D7=93=D7=9E?= (=?UTF-8?Q?Shahar_Kadmiel_=D7=A9=D7=97=D7=A8_=D7=A7=D7=93=D7=9E?=) Date: Tue, 21 Apr 2009 12:25:42 +0300 Subject: [SAC-HELP] VSPACE? Message-ID: <3D6CD373-8A5D-480D-AC91-5129EE1ED47A@bgu.ac.il> I am working on a Macbook pro connected to another monitor in "split screen" mode. When I plot, XWindows comes up split between both screens - this is very annoying. Using VSPACE I tried to change that but only the aspect ratio of the plot changed - the window still came up split between the two screens. XVPORT didn't do the job either. How do I make XWindows to come up only on one screen? SAC ver. 101.2 OS X 10.5.6 From chad at iris.washington.edu Tue Apr 21 07:50:01 2009 From: chad at iris.washington.edu (Chad Trabant) Date: Tue, 21 Apr 2009 07:50:01 -0700 Subject: [SAC-HELP] VSPACE? In-Reply-To: <3D6CD373-8A5D-480D-AC91-5129EE1ED47A@bgu.ac.il> References: <3D6CD373-8A5D-480D-AC91-5129EE1ED47A@bgu.ac.il> Message-ID: <5084DFB8-8E2A-4DF5-8353-FCEED1B6A2B9@iris.washington.edu> I've never heard of that specific issue, but as a long shot you might try updating the X11 server (Xquartz) running on your Mac: http://xquartz.macosforge.org/trac/wiki Chadd On Apr 21, 2009, at 2:25 AM, Shahar Kadmiel ??? ?????? wrote: > I am working on a Macbook pro connected to another monitor in "split > screen" mode. When I plot, XWindows comes up split between both > screens - this is very annoying. > Using VSPACE I tried to change that but only the aspect ratio of the > plot changed - the window still came up split between the two > screens. XVPORT didn't do the job either. How do I make XWindows to > come up only on one screen? > > SAC ver. 101.2 > OS X 10.5.6 > _______________________________________________ > sac-help mailing list > sac-help at iris.washington.edu > http://www.iris.washington.edu/mailman/listinfo/sac-help > From snoke at vt.edu Fri Apr 24 11:36:39 2009 From: snoke at vt.edu (Arthur Snoke) Date: Fri, 24 Apr 2009 14:36:39 -0400 (EDT) Subject: [SAC-HELP] polezero option Message-ID: We are preparing the next update for SAC, and I have been looking at some "help" files called from within SAC (and in the computer accessible manual), and have changed a few. Because there were several e-mail exchanges regarding the polezero option of transfer, I looked closely at SAC> help transfer I am attaching my first draft for a replacement of that section of the transfer help command. Please share comments/corrections, etc. Others I have already worked on are 04graphics, 09file_format, begindevices, enddevices. If there are others you think need updating, please share. It is more likely they will be included if you send me a suggested revision! Finally, I have written a C program for doing endian swapping for .sgf files (SAC Graphics Format files). I have tested it on several platforms, but if someone would like to try it -- or just want an advance copy -- let me know. Arthur Snoke snoke at vt.edu -------------- next part -------------- SAC Command Reference Manual TRANSFER SUMMARY: Performs deconvolution to remove an instrument response and convolution to apply another instrument response. SYNTAX: TRANSFER {FROM type {options}} , {TO type {options}} , {FREQLIMITS f1 f2 f2 f4} , {PREWHITENING ON|OFF|n} INPUT: FROM type : Remove the instrument type by deconvolution. The allowed instrument types and their options are listed in a table below. TO type : Insert the instrument type by convolution. The allowed instrument types and their options are listed in a table below. FREQLIMITS f1 f2 f3 f4 : This is a low- and high-pass taper that can be used to filter the spectrum. f1 and f2 specify the high-pass filter and corresponds to the frequencies over which the taper is applied. The taper is zero below f1 and unity above f2. f3 and f4 specify the low-pass filter and correspond to the frequencies over which the taper is applied. The taper is unity below f3 and zero above f4. The defaults provide no tapering for any realistic seismic signal. Note that the filter applied by TRANSFER is acausal. If it is important to preserve the character of signal onsets, you may want to use the default values for FREQLIMITS and filter the output signal using a single-pass filter of your design. PREWHITENING {ON} : Turn on prewhitening in the time domain before spectral operations, and compensating dewhitening in the time domain after spectral operations. Initially, the option is off. If the user turns it on without specifying the order, it will default to 6, unless the order has been changed in the WHITEN command. PREWHITENING OFF : Turn off prewhitening. PREWHITENING n : Turn on prewhitening and change the prewhitening order to n. Available instrument types: *ACC acceleration BBDISP Blacknest specification of Broadband Displacement BBVEL Blacknest specification of Broadband Velocity BENBOG Blacknest specification of Benioff by Bogert **DBASE search database for applicable file: EVALRESP, POLEZERO, or FAP Note: In order to use the DBASE type, the user must have access to an Oracle database with links to the applicable files, the database must be formatted as described below, and the user must have the Oracle version of sac2000. DSS LLNL Digital Seismic System DWWSSN Digital World Wide Standard Seismograph Station EKALP6 Blacknest specification of EKA LP6 EKASP2 Blacknest specification of EKA SP2 ELMAG Electromagnetic **EVALRESP EVRESP code by Thomas J. McSweeney **FAPFILE reads Frequency, Amplitude, Phase file GBALP Blacknest specification of GBA LP GBASP Blacknest specification of GBA SP GENERAL General seismometer GSREF USGS Refraction HFSLPWB Blacknest specification of HFS LPWB IW EYEOMG-spectral differentiation LLL LLL broadband analog seismometer LLSN LLSN L-4 seismometer LNN Livermore NTS Network instrument LRSMLP Blacknest specification of LRSM LP LRSMSP Blacknest specification of LRSM SP *NONE displacement, this is the default NORESS NORESS (NRSA) NORESSHF NORESS high frequency element OLDBB Old Blacknest specification of BB OLDKIR Old Blacknest specification of Kirnos **POLEZERO reads Pole Zero file PORTABLE Portable seismometer with PDR2 PTBLLP Blacknest specification of PTBL LP REDKIR Blacknest specification of RED Kirnos REFTEK Reftek 97-01 portable instrument RSTN Regional Seismic Test Network S750 S750 Seismometer SANDIA Sandia system 23 instrument SANDIA3 Sandia new system with SL-210 SRO Seismic Research Observatory *VEL velocity WA Wood-Anderson WABN Blacknest specification of Wood-Anderson WIECH Wiechert seismometer WWLPBN Blacknest specification of WWSSN long period WWSP WWSSN short period WWSPBN Blacknest specification of WWSSN short period YKALP Blacknest specification of YKA long period YKASP Blacknest specification of YKA short period *Note: ACC, VEL, and NONE do not refer to actual seismometer specifications but to acceloration, velocity, and displacement respectively. When these are specified as the TO type, IDEP is set accordingly. **Note: DBASE, EVALRESP, FAPFILE, and POLEZERO do not refer to actual seismometer specifications. They are described in greater detail below. options : A set of zero or more of the following depending upon the specific instrument type: SUBTYPE subtype the following types use the following subtypes: FAP: name of file to be read LLL: LV, LR, LT, MV, MR, MT, EV, ER, ET, KV, KR, KT LNN: BB, HF NORESS: LP, IP, SP POLEZERO: name of file to be read RSTN: [CP, ON, NTR, NY, SD][KL, KM, KS, 7S][Z, N, E] SANDIA: [N, O][T, L, B, D, N, E][V, R, T] SRO: BB, SP, LPDE FREEPERIOD v the following types use FREEPERIOD: ELMAG, GENERAL, IW, LLL SUBTYPE BB, REFTEK (v must be 15.0 or 30.0 for ELMAG) MAGNIFICATION n the following types use MAGNIFICATION: ELMAG, GENERAL (n must be 375, 750, 1500, 3000, or 6000 for ELMAG) NZEROS n the following types use NZEROS: GENERAL, IW DAMPING v the following types use DAMPING: GENERAL, LLL SUBTYPE BB, REFTEK CORNER v the following types use CORNER: LLL SUBTYPE BB, REFTEK GAIN v HIGHPASS v the following types use HIGHPASS: REFTEK The following options are used with the EVRESP option. FNAME filename STATION sta CHANNEL chan NETWORK ntwk DATE date TIME time DEFAULT VALUES: TRANSFER FROM NONE TO NONE FREQUENCY -2. -1. 1.E5 1.E6 DESCRIPTION: This command can be used to alter the instrument response of seismic data. It is a modification of the program TRANSFER developed by Keith Nakanishi. A frequency domain deconvolution by spectral division is used to remove an instrument response, and a frequency domain convolution by spectral multiplication is used to insert a new instrument response. Most of the implementation is done using double-precision (64-bit) arithmetic. If the FROM instrument type is NONE, then no instrument is removed, and the original trace is presumed to be a displacement. This is useful for adding instrument responses to synthetic seismograms. If TO type is NONE, then no instrument is inserted. Many of the instruments have options which further specify the response. The most common of these options is the instrument subtype. A few instruments require that certain numerical parameters be specified, and do not use the subtype option. For a list of instruments, and a list of the instruments that use subtypes or other parameters, see the tables below. Optional frequency domain cosine tapering can be used to select a bandlimited response. Optional prewhitening can also be used to flatten the spectrum of the input time series before transforming in the frequency domain. This should reduce the dynamic range of the spectral values, and improve the accuracy of the overall operation at high frequencies for seismic data. The header field SCALE is set to 1.0, to prevent redundant scaling. Unless other units are expected for a given instrument, the TRANSFER's returned values will be in nanometers (or nm/sec, or nm/sec/sec, etc). When the EVRESP option is used, the values are conveted to nm before they are returned to the user. In versions 58 and 58a-58e, there was an inconsistency; values were being returned in nm except in the case of EVALRESP, which returned the values in meters. In addition, the NANO option was provided which, when turned on, would multiply the values by 1e09 before returning. This option had the effect of converting meters to nm, but the uninteded consequence was that it converted nm to something much much smaller. In version 59, this inconsistancy has been removed, and so has the NANO option. EXAMPLES: To remove the instrument response from the RSTN station NYKM.Z and apply the instrument response for DSS without pre- whitening: u: READ NYKM.Z u: TRANS FROM RSTN SUBTYPE NYKM.Z TO DSS PREW OFF To remove the LLL broadband instrument response and apply the SRO instrument response with frequency tapering and prewhitening: u: READ ABC.Z u: TRANS FROM LLL TO SRO FREQ .02 .05 1. 2. PREW 2 The passband of the resulting trace will be flat from .05 Hz to 1 Hz and will be zero below .02 Hz and above 2 Hz. Prewhitening of order 2 is applied in the time domain before deconvolution and the effect is removed in the time domain after convolution. To transfer from the electromagnetic instrument response to displacement: u: READ XYZ.Z u: TRANSFER FROM ELMAG FREEP 15. MAG 750. TO NONE POLEZERO OPTION: One of the instrument types is called POLEZERO. This option uses the Omega (Omega\) convention. This type lets you describe a general instrument response by specifying a file which contains its poles and zeros. The options in the file are keyword driven and the numbers are in free format. You may specify a multiplicative scaling constant by putting a line in the file containing the keyword "CONSTANT" followed by a floating point number. The default for this constant is 1.0 if you omit this line. You specify the number of poles by putting a line in the file with the keyword "POLES" following by an integer number. The next lines in the file until another keyword is read become the poles for this instrument. Each such line contains two floating point numbers specifying the real and imaginary parts of one of the poles. If you have fewer lines specifying poles than you stated on the "POLES" line, the remaining poles are assumed to lie at the origin. You specify the zeros in the same way with a "ZEROS" keyword line following by lines specifying the zeros that do not lie at the origin. You may specify up to 15 poles and 15 zeros. For example, the following is the specification for the SRO broadband seismometer: ZEROS 4 -0.125 0.0 -50.0 0.0 POLES 4 -0.13 0.0 -6.02 0.0 -8.66 0.0 -35.2 0.0 CONSTANT -394.0 Notice that since two of the zeros are at the origin, they don't have to be specified in the file. Also notice that the options may appear in any order in the file. To use this option you specify the type to be POLEZERO and the subtype to be the name of the file. This may be a file in the current directory or in some other directory if you specify the absolute or relative pathname. It may also the the name of a global file contained in the "polezero" subdirectory of the "sacaux" directory. By putting a file in this global directory, anyone on your system can easily use it. Nakanishi, K., "Computer code for the transfer function of seismic systems", Lawrence Livermore National Lab., UCID-18071, 1979. EXAMPLE: suppose the file was named sro.pz and you want to remove the instrument response from station ABC.Z. u: READ ABC.Z u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE EVALRESP OPTION: This option enables the application of transfer functions extracted from SEED data volumes using the evresp code (Version 3.2.x) by Thomas J. McSweeney or rdseed (Version 4.1.x). The RESP files must be in the current directory or must be specified by full path and name. To identify the correct RESP file and to extract the proper transfer function from that file, EVALRESP uses information from the SAC headers. The fields are station (KSTNM), channel (KCMPNM), date and time (KZDATE & KZTIME), network (KNETWK), and location ID. Location ID is refered to as LOCID; it distinguishes between multiple seismometers with the same station and channel names, operating at the same time. Data received from IRIS in SAC format (or converted to SAC with RDSEED) will have KHOLE set to a valid LOCID if one is necessary. If the user is informed of real LOCIDs in the EVALRESP file, the user can set KHOLE with CH (HELP CH for details). SAC will use KHOLE as LOCID if it is a two character alpha-numeric string (padded with spaces or not). At the present time (7/19/2000), LOCID is useful in a small number of cases. It is possible to override the header values by specifying additional options to EVALRESP. The possible options are: STATION CHANNEL NETWORK DATE TIME LOCID FNAME and each option must be followed by an appropriate value. If DATE is not set in the header and is not specified as an option, then the current date is used in the search. If TIME is not set in the seismogram header and is not specified as an option, then the current system time is used in the search. If network is not specified, then the search for a transfer function defaults to use any network. If LOCID is not set at the command line or in KHOLE, then the search for the transfer function defaults to use any LOCID. If TYPE is not specified and is not set in the seismogram header then a velocity transfer function is computed. To force TRANSFER to use a specific SEED response file use the FNAME option followed by the filename. EXAMPLES: To remove the instrument response from the seismogram in memory (assuming a response file exists): u: TRANSFER FROM EVALRESP To remove the instrument response from 16.42.05.5120.TS.PAS.BHZ.SAC and apply the response from station COL, channel BHZ for the same time period: u: r 16.42.05.5120.TS.PAS.BHZ.SAC u: TRANSFER FROM EVALRESP TO EVALRESP STATION COL To plot the instrument response in units of displacement for station COL, channel BHZ, network IU, for the date 1992/02 and time 16:42:05: u: funcgen impulse npts 16384 delta .05 begin 0 u: transfer to evalresp station COL channel BHZ network IU type DIS date & 1992/2 time 16:42:05 u: fft u: psp am (NOTE: the & only indicates a continued line in the documentation.) To remove the instrument response from 16.42.05.5120.TS.PAS.BHZ.SAC using a response contained in file /tmp/Responses/RESP.TS.PAS.BHZ: u: r 16.42.05.5120.TS.PAS.BHZ.SAC u: TRANSFER FROM EVALRESP FNAME /tmp/Responses/RESP.TS.PAS.BHZ TO NONE DBASE OPTION: Note: In order to use the DBASE type, the user must have access to an Oracle database with links to the applicable files, the database must be formatted as described below, and the user must have the Oracle version of sac2000. This option enables the deconvolution of transfer functions extracted from SEED response files using the evresp Version 3.2.6 code by Thomas J. McSweeney. The response files are assumed to have been extracted from SEED (VERSION 4.1.x), and the locations of the appropriate files must be stored in an accessible Oracle database using the INSTRUMENT and SENSOR tables of the CSS 3.0 schema. (See help for the READDB command for more information on the database requirements.) Fields which must be set are: instrument.inid instrument.dir instrument.dfile instrument.rsptype sensor.sta sensor.chan sensor.time sensor.endtime sensor.inid The instrument.rsptype fields must contain the string 'evresp' and the remaining fields must be set as appropriate to join and point to the correct dir and dfile given the correct station, channel, and time. The DBASE option can only be used after the keyword FROM. In other words, TRANSFER FROM DBASE is OK but TRANSFER TO DBASE is not. If the database query is unsuccessful, TRANSFER will attempt to find an appropriate response file in the current directory. If that fails, the seismogram is not modified. FAPFILE OPTION: This option is similar to the POLEZERO option, but instead reads a Frequency - Amplitude - Phase (FAP) file in the standard format used at the Center for Monitoring Research (pIDC). A (partial) example of such a file is shown below. # # Displacement response for Array # # Example: ST01 z # # Geotech 23900 seismometer # # Phase unwrapped # theoretical 0 instrument fap Organization 40 0.100000 1.576582e-01 -52.923801 0.000000 0.000000 0.125990 3.511520e-01 -61.669102 0.000000 0.000000 0.200000 1.634426e+00 -79.966599 0.000000 0.000000 0.368400 1.171214e+01 -107.522003 0.000000 0.000000 0.500000 3.135000e+01 -126.447998 0.000000 0.000000 0.683990 8.322500e+01 -155.035004 0.000000 0.000000 0.800000 1.273452e+02 -174.207001 0.000000 0.000000 In this format, lines starting with a "#" sign are comments. The line: theoretical 0 instrument fap Organization is ignored by SAC. The next line ("40") is the number of fap lines to follow. The remaining lines are frequency, amplitude, phase, amplitude error, and phase error. The error columns are not used by SAC, but must be present in order for the file to be parsed correctly. EXAMPLE: suppose the fap file was named ABC.PAZ and you want to remove the instrument response from station ABC.Z. u: READ ABC.Z u: TRANSFER FROM FAPFILE SUBTYPE ABC.PAZ TO NONE SEE COMMANDS: WHITEN ACKNOWLEDGEMENTS: Roger Hanscom did the original conversion of Keith Nakanishi's TRANSFER program. George Randall added the prewhitening option and was a major contributor to the testing and documentation of this command. LATEST REVISION: May 06, 1998 (Version 00.57) From snoke at vt.edu Fri Apr 24 12:25:37 2009 From: snoke at vt.edu (Arthur Snoke) Date: Fri, 24 Apr 2009 15:25:37 -0400 (EDT) Subject: [SAC-HELP] polezero option -- correct file this time Message-ID: Unfortunately, the file I sent was the unaltered "transfer' help file, rather than my revised "polezero" subset of that file. The desired file (I hope) is attached. ---------- Forwarded message ---------- Date: Fri, 24 Apr 2009 14:36:39 -0400 (EDT) From: Arthur Snoke To: SAC-help Listserv Subject: [SAC-HELP] polezero option We are preparing the next update for SAC, and I have been looking at some "help" files called from within SAC (and in the computer accessible manual), and have changed a few. Because there were several e-mail exchanges regarding the polezero option of transfer, I looked closely at SAC> help transfer I am attaching my first draft for a replacement of that section of the transfer help command. Please share comments/corrections, etc. Others I have already worked on are 04graphics, 09file_format, begindevices, enddevices. If there are others you think need updating, please share. It is more likely they will be included if you send me a suggested revision! Finally, I have written a C program for doing endian swapping for .sgf files (SAC Graphics Format files). I have tested it on several platforms, but if someone would like to try it -- or just want an advance copy -- let me know. Arthur Snoke snoke at vt.edu -------------- next part -------------- POLEZERO OPTION: POLEZERO is an instrument type that can be used to put in or take out the (analog) seismometer response. A good reference is Appendix C in the SEED manual. The current version can be downloaded from IRIS at URL , and a good way to get a polezero file in the correct format is to download data as a SEED volume and use program rdseed to extract the data, the polezero file(s) and the response file. Program rdseed can be downloaded from the same Web site. The response file for a specified channel/station is useful to see the "response in" and "response out" units for the transfer function. Typically, the "response in" listed in the response file is velocity, in m/s, but the polezero file has a "response in" of displacement. A polezero file is a listing of complex zeros and poles of a causal filter that represents the seismometer. The transfer function is of the form (s-z1)(s-z2)...*s-zn) _____________________ s-p1))(s-p2)...*s-pm) where the z1 ... zn are the N zeros and the p1 ... pm are the m poles of the transfer function. The convention used is a Laplacian transform, with s = 2\pi i f with f the frequency in Hz. The sign convention is e^{-st} for the forward transform (from the t domain to the s domain). Here is a polezero file for the LHZ channel from station JCC returned by program rdseed for a 28 June 2007 teleseism: ZEROS 3 POLES 5 -0.0370 0.0370 -0.0370 -0.0370 -118.7520 423.4880 -118.7520 -423.4880 -251.3270 0.0000 CONSTANT 3.056572e+16 For this transfer function, there are five poles, for which the complex values are listed on the five lines following the line POLES 5. Also there are three zeros. None are listed, and the convention is that an unlisted zero has the value of zero. Hence if there were five zeros, for which three were actually zero, one could either write out five lines for which three of them would be 0.00 0.00 and the other two the complex, nonzero values, or one could have ZEROs 5 with only the two nonzero zeros explicitly written out. In the response file for this channel, there are only two zeros because the "response in" is velocity but rdseed "knows" that the user wants to work with waveforms corrected to displacement. The CONSTANT is a multiplicative factor that rescales the "response in" units to the "response out" units at the normalization frequency. The derivation of CONSTANT is described in the SEED manual and can be pieced together for a particular channel from that channel's response file. The default for CONSTANT is 1.0, the options can be written in any order, and one can add a comment line by starting that line with a * (asterisk). To use this option you specify the type to be POLEZERO and the subtype to be the name of the file. This may be a file in the current directory or in some other directory if you specify the absolute or relative pathname. It may also the the name of a global file contained in the sac subdirectory sac/aux/polezero/. By putting a file in this global directory, anyone on your system can easily use it. EXAMPLE: suppose the file was named sro.pz and you want to remove the instrument response from station ABC.Z. u: READ ABC.Z u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE From icrazy at gmail.com Fri Apr 24 13:10:24 2009 From: icrazy at gmail.com (Kuang He) Date: Fri, 24 Apr 2009 16:10:24 -0400 Subject: [SAC-HELP] polezero option -- correct file this time In-Reply-To: References: Message-ID: On Fri, Apr 24, 2009 at 3:25 PM, Arthur Snoke wrote: > Unfortunately, the file I sent was the unaltered "transfer' help file, > rather than my revised "polezero" subset of that file. ?The desired file (I > hope) is attached. Dear Arthur, There is something wrong with the equation. The following equation has some unbalanced parentheses. (s-z1)(s-z2)...*s-zn) _____________________ s-p1))(s-p2)...*s-pm) Best regards, -- Kuang From george at gly.bris.ac.uk Sat Apr 25 06:14:53 2009 From: george at gly.bris.ac.uk (George Helffrich) Date: Sat, 25 Apr 2009 14:14:53 +0100 Subject: [SAC-HELP] polezero option In-Reply-To: References: Message-ID: <8f6df5f9262e66fb21efb18a653696f6@gly.bris.ac.uk> Dear All - I will provide a rewrite suggestion after some further research. Here are my initial comments, however. ---- POLEZERO OPTION: %%%Comments indicated flagged with this notation. %%%This paragraph is jumbled. It confusingly combines information about %%%the concepts underlying a pole-zero representation with the way to specify %%%a response to SAC. They should be separated. POLEZERO is an instrument type that can be used to put in or take out the (analog) seismometer response. A good reference is Appendix C in the SEED manual. The current version can be downloaded from IRIS at URL , and a good way to get a polezero file in the correct format is to download data as a SEED volume and use program rdseed to extract the data, the polezero file(s) and the response file. Program rdseed can be downloaded from the same Web site. The response file for a specified channel/station is useful to see the "response in" and "response out" units for the transfer function. Typically, the "response in" listed in the response file is velocity, in m/s, but the polezero file has a "response in" of displacement. %%%As Kuang He points out, this equation is syntactically incorrect. Pole-zero %%%filters aren't causal, either! %%%Using TeX-style expressions isn't a good idea -- it assumes the reader knows %%%TeX, when many use nothing more than Word to typeset equations. Lay them %%%out graphically in text, assuming a fixed-pitch font. A polezero file is a listing of complex zeros and poles of a causal filter that represents the seismometer. The transfer function is of the form (s-z1)(s-z2)...*s-zn) _____________________ s-p1))(s-p2)...*s-pm) where the z1 ... zn are the N zeros and the p1 ... pm are the m poles of the transfer function. The convention used is a Laplacian transform, with s = 2\pi i f with f the frequency in Hz. The sign convention is e^{-st} for the forward transform (from the t domain to the s domain). Here is a polezero file for the LHZ channel from station JCC returned by program rdseed for a 28 June 2007 teleseism: ZEROS 3 POLES 5 -0.0370 0.0370 -0.0370 -0.0370 -118.7520 423.4880 -118.7520 -423.4880 -251.3270 0.0000 CONSTANT 3.056572e+16 %%%The information about the input units and output units needs to be presented %%%more clearly. The description here jumbles what rdseed does with what SAC %%%does. For this transfer function, there are five poles, for which the complex values are listed on the five lines following the line POLES 5. Also there are three zeros. None are listed, and the convention is that an unlisted zero has the value of zero. Hence if there were five zeros, for which three were actually zero, one could either write out five lines for which three of them would be 0.00 0.00 and the other two the complex, nonzero values, or one could have ZEROs 5 with only the two nonzero zeros explicitly written out. In the response file for this channel, there are only two zeros because the "response in" is velocity but rdseed "knows" that the user wants to work with waveforms corrected to displacement. The CONSTANT is a multiplicative factor that rescales the "response in" units to the "response out" units at the normalization frequency. The derivation of CONSTANT is described in the SEED manual and can be pieced together for a particular channel from that channel's response file. The default for CONSTANT is 1.0, the options can be written in any order, and one can add a comment line by starting that line with a * (asterisk). To use this option you specify the type to be POLEZERO and the subtype to be the name of the file. This may be a file in the current directory or in some other directory if you specify the absolute or relative pathname. It may also the the name of a global file contained in the sac subdirectory sac/aux/polezero/. By putting a file in this global directory, anyone on your system can easily use it. EXAMPLE: suppose the file was named sro.pz and you want to remove the instrument response from station ABC.Z. u: READ ABC.Z u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE On 24 Apr 2009, at 20:25, Arthur Snoke wrote: > Unfortunately, the file I sent was the unaltered "transfer' help file, > rather than my revised "polezero" subset of that file. The desired > file (I hope) is attached. > > ---------- Forwarded message ---------- > Date: Fri, 24 Apr 2009 14:36:39 -0400 (EDT) > From: Arthur Snoke > To: SAC-help Listserv > Subject: [SAC-HELP] polezero option > > We are preparing the next update for SAC, and I have been looking at > some "help" files called from within SAC (and in the computer > accessible manual), and have changed a few. Because there were > several e-mail exchanges regarding the polezero option of transfer, I > looked closely at > > SAC> help transfer > > I am attaching my first draft for a replacement of that section of the > transfer help command. Please share comments/corrections, etc. > > Others I have already worked on are 04graphics, 09file_format, > begindevices, enddevices. > > If there are others you think need updating, please share. It is more > likely they will be included if you send me a suggested revision! > > Finally, I have written a C program for doing endian swapping for .sgf > files (SAC Graphics Format files). I have tested it on several > platforms, but if someone would like to try it -- or just want an > advance copy -- let me know. > > Arthur Snoke > snoke at vt.edu_______________________________________________ > sac-help mailing list > sac-help at iris.washington.edu > http://www.iris.washington.edu/mailman/listinfo/sac-help > George Helffrich george at geology.bristol.ac.uk From sac-help at iris.washington.edu Sat Apr 25 22:39:27 2009 From: sac-help at iris.washington.edu (VIAGRA ® Official Site) Date: Sat, 25 Apr 2009 22:39:27 -0700 (PDT) Subject: [SAC-HELP] SALE 70% 0FF on Pfizer Message-ID: <200904260539.n3Q5dRgI029239@norman.iris.washington.edu> An HTML attachment was scrubbed... URL: From snoke at vt.edu Sun Apr 26 06:26:24 2009 From: snoke at vt.edu (Arthur Snoke) Date: Sun, 26 Apr 2009 09:26:24 -0400 (EDT) Subject: [SAC-HELP] polezero option In-Reply-To: <8f6df5f9262e66fb21efb18a653696f6@gly.bris.ac.uk> References: <8f6df5f9262e66fb21efb18a653696f6@gly.bris.ac.uk> Message-ID: Thank you George and Kuang-He for comments. Kuang-He picked up on a typo in the equation I wrote. I wrote him off list with a corrected version that he said was okay: (s-z1)*(s-z2)*...*(s-zn) ________________________ (s-p1)*(s-p2)*...*(s-pm) I give some replies to George's comments below. I welcome comments/suggestions/corrections from others as well. > %%%Comments indicated flagged with this notation. > %%%This paragraph is jumbled. It confusingly combines information about > %%%the concepts underlying a pole-zero representation with the way to specify > %%%a response to SAC. They should be separated. I agree that the paragraph could be improved, and am looking for better ways to untangle SAC from RDSEED. A couple of things came up as I was writing this: 1. There is a question of units: the RDSEED "response in" units use m as a length measure, while SAC's IDEP uses nm. I doubt that either are going to change, but I welcome suggestions to state this efficiently. 2. As i note, the values given for the polezero transfer function in the RESP file is for velocity "response in" (with two zeros) but the polezero file returned by RDSEED is for displacement (three zeros). Is there nothing within RDSEED that makes that clear? Or am I missing something? > %%%filters aren't causal, either! The polezero transfer functions are analog filters and in themselves are causal. The one I give as an example is an STS-2 response function, which is mostly a damped harmonic oscillator. (Aside: I have read that there are three versions/generations of STS-2 seismometers, but so far as I can tell the analog-stage response is always the same. Can anyone clarify?) > %%%Using TeX-style expressions isn't a good idea -- it assumes the reader > %%%knows TeX, when many use nothing more than Word to typeset equations. > %%%Lay them out graphically in text, assuming a fixed-pitch font. As of now, SAC help files use 7-bit ASCII. The minimal use I made of TeX notation should be transparent to anyone who understands what a Laplace transform is. Note I resisted the temptation to use \cdots in the equation above. Given that one cannot underline letters in 7-bit ASCII, I have not figured out a good way to show the subset of letters need (e.g., TRANS for TRANSFER). > > %%%The information about the input units and output units needs to be > %%%presented more clearly. The description here jumbles what rdseed > %%%does with what SAC does. See above comment. > > u: READ ABC.Z > > u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE > I do not use SAC to do my instrument correction, but I do use polezero files. The above example as written would probably get one in trouble at very low frequencies, as all seismometers have zero response at zero frequency. If I understand the notation correctly, "FROM" means a deconvolution, which means it divides the input waveform by, in this case, the polezero expression. To avoid the output blowing up, this expression should be amended to include the FREQLIMITS option. Putting these in definitely makes the total transfer function noncausal. Arthur Snoke From george at gly.bris.ac.uk Mon Apr 27 05:26:47 2009 From: george at gly.bris.ac.uk (George Helffrich) Date: Mon, 27 Apr 2009 13:26:47 +0100 Subject: [SAC-HELP] Fwd: polezero option Message-ID: <349209c81a3b21abe76856c99d8a9f2f@gly.bris.ac.uk> Dear All - My rewrite will arrive in a separate posting anon. Some comments on Arthur's: On 26 Apr 2009, at 14:26, Arthur Snoke wrote: > Thank you George and Kuang-He for comments. Kuang-He picked up on a > typo in the equation I wrote. I wrote him off list with a corrected > version that he said was okay: > > (s-z1)*(s-z2)*...*(s-zn) > ________________________ > > (s-p1)*(s-p2)*...*(s-pm) > > ... > >> %%%filters aren't causal, either! > > The polezero transfer functions are analog filters and in themselves > are causal. The analog filter response that the pole-zero description represents is causal, but pole-zero descriptions are not necessarily causal. That's the statement that I wanted to correct -- am I wrong? > The one I give as an example is an STS-2 response function, which is > mostly a damped harmonic oscillator. (Aside: I have read that there > are three versions/generations of STS-2 seismometers, but so far as I > can tell the analog-stage response is always the same. Can anyone > clarify?) > >> %%%Using TeX-style expressions isn't a good idea -- it assumes the >> reader %%%knows TeX, when many use nothing more than Word to typeset >> equations. >> %%%Lay them out graphically in text, assuming a fixed-pitch font. > > As of now, SAC help files use 7-bit ASCII. The minimal use I made of > TeX notation should be transparent to anyone who understands what a > Laplace transform is. I don't see a connection between knowing mathematics and knowing TeX. I know mathematics but typeset them with eqn/troff. See my own rewrite in a separate message. > ... >> >> u: READ ABC.Z >> >> u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE >> > > I do not use SAC to do my instrument correction, but I do use polezero > files. The above example as written would probably get one in trouble > at very low frequencies, as all seismometers have zero response at > zero frequency. SeisMac doesn't! It is an accelerometer, but that can be a seismometer, too. > If I understand the notation correctly, "FROM" means a deconvolution, > which means it divides the input waveform by, in this case, the > polezero expression. To avoid the output blowing up, this expression > should be amended to include the FREQLIMITS option. Putting these in > definitely makes the total transfer function noncausal. > So are pole-zero responses acausal, or are only band-limited ones acausal? George Helffrich george at geology.bristol.ac.uk From george at gly.bris.ac.uk Mon Apr 27 05:30:51 2009 From: george at gly.bris.ac.uk (George Helffrich) Date: Mon, 27 Apr 2009 13:30:51 +0100 Subject: [SAC-HELP] Polezero rewrite Message-ID: <2b2d85e8b281a70473afac5000ae9b4f@gly.bris.ac.uk> Dear All - Here's my rewrite of the polezero response removal text to clarify some of the issues raised in the version proposed earlier. For sanity, use a fixed-pitch font to view the text. ------ POLEZERO OPTION: One of the instrument types is called POLEZERO. This type lets you describe a general instrument response by specifying a file which contains its poles and zeros. The options in the file are keyword driven and the numbers are in free format. You may specify a multiplicative scaling constant A0 by putting a line in the file containing the keyword "CONSTANT" followed by a floating point number. The default for this constant is 1.0 if you omit this line. You specify the number of poles by putting a line in the file with the keyword "POLES" following by an integer number. The next lines in the file until another keyword is read become the poles for this instrument. Each such line contains two floating point numbers specifying the real and imaginary parts of each of the poles. If you have fewer lines specifying poles than you stated on the "POLES" line, the remaining poles are assumed to be numerically zero. You specify the zeros in the same way with a "ZEROS" keyword line following by lines specifying the non-zero zeros. You may specify up to 15 poles and 15 zeros. For example, the following is the specification for the SRO broadband seismometer: ZEROS 4 -0.125 0.0 -50.0 0.0 POLES 4 -0.13 0.0 -6.02 0.0 -8.66 0.0 -35.2 0.0 CONSTANT -394.0 Notice that since two of the zeros are at the origin, they don't have to be specified in the file. Also notice that the options may appear in any order in the file. If there are any nonzero imaginary parts to a pole or zero, they must appear as conjugate pairs to make the response purely real. SAC uses the omega convention for the pole-zero response: the frequency w = 2*pi*i*f, where f is frequency in Hz and i is the imaginary unit (sqrt(-1)). Thus, if an instrument manufacturer specifies that a pole is at 1 Hz on the real axis, the SAC pole's real and imaginary parts would be (6.28, 0). The response H(w) is the ratio of the product of the difference between w and each of the np poles and nz zeros: (w-z )*(w-z )*...*(w-z ) 1 2 nz H(w) = ------------------------- (w-p )*(w-p )*...*(w-p ) 1 2 np For conversion of a seismometer's analog output to a physical unit (m, m/sec, m/sec**2), there are two specific frequencies that are important: the normalization frequency wn, and the sensitivity frequency, ws. The normalization frequency is the frequency at which the product A0*H(wn) = 1.0 A0 is the CONSTANT value specified in the response. The sensitivity S of the instrument is the value by which A0*H(w) should be multiplied to get the appropriate physical unit. To avoid unnecessary complications in applying instrument corrections, wn and ws should be equal. If they are, then by multiplying the signal by S before applying the transfer function, the correct physical units are produced. If not, you must multiply by S*H(ws)/H(wn). If convenient, you can combine S and A0 and set CONSTANT to be their product S*A0. SAC assumes that when you apply your pole-zero instrument correction, it will yield displacement. If this is not the physical unit yielded in your instrument response, dividing or multiplying by w will respectively integrate or differentiate the response. Thus if your instrument response is velocity (m/sec), then adding an extra zero with value zero will yield displacement. Conversely, if your instrument response is displacement and you want velocity as your physical unit, add an extra pole with value zero (but this is not what SAC would expect of the response). To use this option you specify the type to be POLEZERO and the subtype to be the name of the file. This may be a file in the current directory or in some other directory if you specify the absolute or relative pathname. It may also the the name of a global file contained in the "polezero" subdirectory of the "sacaux" directory. By putting a file in this global directory, anyone on your system can easily use it. REFERENCES: Hutt, C. R., "Specifying and using channel response information", Appendix C, SEED Reference Manual, version 2.4, 2006; available online from . Nakanishi, K., "Computer code for the transfer function of seismic systems", Lawrence Livermore National Lab., UCID-18071, 1979. EXAMPLE: suppose the file was named sro.pz and you want to remove the instrument response from station ABC.Z. u: READ ABC.Z u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE ------ George Helffrich george at geology.bristol.ac.uk From renate at ess.washington.edu Mon Apr 27 10:49:49 2009 From: renate at ess.washington.edu (Renate Hartog) Date: Mon, 27 Apr 2009 10:49:49 -0700 (PDT) Subject: [SAC-HELP] Polezero rewrite In-Reply-To: <2b2d85e8b281a70473afac5000ae9b4f@gly.bris.ac.uk> References: <2b2d85e8b281a70473afac5000ae9b4f@gly.bris.ac.uk> Message-ID: Hello Everyone, I don't have time to work on a true edit, but I do applaud you all for working on a better explanation of the POLE ZERO option for TRANSFER since it seems to generate a lot of confusion. Here are the few points that add to the confusion in my opinion: 1) Transfer's SAC HELP says that the NONE type is Displacment. If NONE is as I interpret it, namely, don't deconvolve or convolve with anything, then there is no longer a units issue. You can just use the native response units as specified in de SEED file and get out the units you'd expect. You could even leave out the extra zero(s) and get velocity or acceleration, whichever you want. 2) The fact that SAC defaults to Displacement in nm, is only relevant if you want to put in, or take out, one of the pre-programmed instrument types. 3) rdseed does add the extra zeros to its SAC_PZ files to result in a Displacement response, however, it outputs a CONSTANT that is A0*S that results in the signal that are usually (THANK GOODNESS) in SI, m/s or m/s**2 (depending on the units-in field of the SEED file) if you use TRANSFER FROM POLEZERO rdseed-output-file TO NONE. To make all this clear, you don't only need to edit the POLEZERO part of the transfer help, but also the other parts of TRANSFER. And Rdseed could use some more information about the SAC_PZ output file in its man-page. -Renate Renate Hartog PNSN/UW Seismology lab. On Mon, 27 Apr 2009, George Helffrich wrote: > Dear All - > > Here's my rewrite of the polezero response removal text to clarify > some of the issues raised in the version proposed earlier. For sanity, use a > fixed-pitch font to view the text. > > ------ > > POLEZERO OPTION: > One of the instrument types is called POLEZERO. This type lets you > describe a general instrument response by specifying a file which contains > its poles and zeros. The options in the file are keyword driven and the > numbers are in free format. You may specify a multiplicative scaling > constant A0 by putting a line in the file containing the keyword "CONSTANT" > followed by a floating point number. The default for this constant is 1.0 > if > you omit this line. You specify the number of poles by putting a line in > the > file with the keyword "POLES" following by an integer number. The next > lines > in the file until another keyword is read become the poles for this > instrument. Each such line contains two floating point numbers specifying > the real and imaginary parts of each of the poles. If you have fewer lines > specifying poles than you stated on the "POLES" line, the remaining poles > are > assumed to be numerically zero. You specify the zeros in the same way with > a "ZEROS" keyword line following by lines specifying the non-zero zeros. > You > may specify up to 15 poles and 15 zeros. For example, the following is the > specification for the SRO broadband seismometer: > > ZEROS 4 > > -0.125 0.0 > > -50.0 0.0 > > POLES 4 > > -0.13 0.0 > > -6.02 0.0 > > -8.66 0.0 > > -35.2 0.0 > > CONSTANT -394.0 > > Notice that since two of the zeros are at the origin, they don't have to be > specified in the file. Also notice that the options may appear in any order > in the file. If there are any nonzero imaginary parts to a pole or zero, > they > must appear as conjugate pairs to make the response purely real. > SAC uses the omega convention for the pole-zero response: the > frequency > w = 2*pi*i*f, where f is frequency in Hz and i is the imaginary unit > (sqrt(-1)). Thus, if an instrument manufacturer specifies that a pole is at > 1 > Hz on the real axis, the SAC pole's real and imaginary parts would be > (6.28, 0). The response H(w) is the ratio of the product of the difference > between w and each of the np poles and nz zeros: > > (w-z )*(w-z )*...*(w-z ) > 1 2 nz > H(w) = ------------------------- > (w-p )*(w-p )*...*(w-p ) > 1 2 np > > For conversion of a seismometer's analog output to a physical unit > (m, m/sec, m/sec**2), there are two specific frequencies that are important: > the normalization frequency wn, and the sensitivity frequency, ws. The > normalization frequency is the frequency at which the product A0*H(wn) = 1.0 > A0 is the CONSTANT value specified in the response. The sensitivity S of > the > instrument is the value by which A0*H(w) should be multiplied to get the > appropriate physical unit. To avoid unnecessary complications in applying > instrument corrections, wn and ws should be equal. If they are, then by > multiplying the signal by S before applying the transfer function, the > correct > physical units are produced. If not, you must multiply by S*H(ws)/H(wn). > If > convenient, you can combine S and A0 and set CONSTANT to be their product > S*A0. > SAC assumes that when you apply your pole-zero instrument correction, > it will yield displacement. If this is not the physical unit yielded in > your > instrument response, dividing or multiplying by w will respectively > integrate > or differentiate the response. Thus if your instrument response is velocity > (m/sec), then adding an extra zero with value zero will yield displacement. > Conversely, if your instrument response is displacement and you want > velocity > as your physical unit, add an extra pole with value zero (but this is not > what SAC would expect of the response). > To use this option you specify the type to be POLEZERO and the subtype > to be the name of the file. This may be a file in the current directory or > in > some other directory if you specify the absolute or relative pathname. It > may > also the the name of a global file contained in the "polezero" subdirectory > of the "sacaux" directory. By putting a file in this global directory, > anyone > on your system can easily use it. > > REFERENCES: > Hutt, C. R., "Specifying and using channel response information", > Appendix > C, SEED Reference Manual, version 2.4, 2006; available online from > . > Nakanishi, K., "Computer code for the transfer function of seismic > systems", Lawrence Livermore National Lab., UCID-18071, 1979. > > EXAMPLE: suppose the file was named sro.pz and you want to remove the > instrument response from station ABC.Z. > > u: READ ABC.Z > > u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE > > ------ > > George Helffrich > george at geology.bristol.ac.uk > > _______________________________________________ > sac-help mailing list > sac-help at iris.washington.edu > http://www.iris.washington.edu/mailman/listinfo/sac-help > From chad at iris.washington.edu Mon Apr 27 16:46:47 2009 From: chad at iris.washington.edu (Chad) Date: Mon, 27 Apr 2009 16:46:47 -0700 Subject: [SAC-HELP] polezero option In-Reply-To: References: <8f6df5f9262e66fb21efb18a653696f6@gly.bris.ac.uk> Message-ID: On Apr 26, 2009, at 6:26 AM, Arthur Snoke wrote: > The polezero transfer functions are analog filters and in themselves > are causal. The one I give as an example is an STS-2 response > function, which is mostly a damped harmonic oscillator. (Aside: I > have read that there are three versions/generations of STS-2 > seismometers, but so far as I can tell the analog-stage response is > always the same. Can anyone clarify?) Responding to the aside, there are 3 generations of electronics for STS-2s and three different sets of poles and zeros to represent them. To figure out which generation sensor you might have there are some general guidelines based on date of manufacture, but it remains possible that the electronics were upgraded if the sensor was returned to the factory. The nominal responses for the 3 generations are available in SEED RESP format here: http://www.iris.edu/NRL/sensors/streckeisen/streckeisen_sts2_sensors.html The responses of the different generations only differ significantly at high frequencies. I'm not quite sure how high is too high, I have heard 35Hz signals and above are where the differences between generations become significant. To further complicate matters a "truncated" pole and zero response for STS-2s has been in common use for many years and it is different than any of the factory nominal responses. It generally works fine for all the generations of sensors with the same caveat that it does not represent the sensor at high frequencies. Apologies for the off topic message, seems like useful information to spread around. Chad Trabant IRIS Data Management Center From peterg at llnl.gov Tue Apr 28 09:49:17 2009 From: peterg at llnl.gov (Peter Goldstein) Date: Tue, 28 Apr 2009 09:49:17 -0700 Subject: [SAC-HELP] Fwd: sac on cygwin - getline problem Message-ID: <7.0.0.16.2.20090428094234.04a829e8@llnl.gov> Dear Professor Yamada, Thank you for sharing your problem with getline. This message is being forwarded to our sac-help mailing list which you can sign up for at the following link. http://norman.iris.washington.edu/mailman/listinfo/sac-help Cheers, Peter >X-IronPort-Anti-Spam-Result: >AisCAMKk9kmCNoJUmWdsb2JhbACWaAEBAQEBCAsKBxG4HINzBQ >X-AuditID: 82368249-af190bb000004e92-7d-49f707c39d33 >Date: Tue, 28 Apr 2009 22:42:24 +0900 >From: Masumi Yamada >User-Agent: Thunderbird 2.0.0.17 (Windows/20080914) >To: peterg at llnl.gov >Subject: sac on cygwin >X-Brightmail-Tracker: AAAAAA== > >Dear sac developers, > >I noticed recent version of cygwin has a function 'getline' in the >stdio.h, and that causes conflict with the function in sac source code. >I recommend to change the name of the function. > >co/getline.c: In function `getline': >co/getline.c:36: error: argument "pfd" doesn't match prototype >/usr/include/sys/stdio.h:31: error: prototype declaration >co/getline.c:36: error: argument "pch" doesn't match prototype >/usr/include/sys/stdio.h:31: error: prototype declaration >co/getline.c:36: error: argument "maxlen" doesn't match prototype >/usr/include/sys/stdio.h:31: error: prototype declaration >make[1]: *** [co/getline.o] Error 1 >make: *** [all-recursive] Error 1 > >best regards, > >Masumi >---------------------------------------------------------- >***** Masumi Yamada >***** Assistant Professor >***** >***** Earthquake Hazards Division, DPRI, Kyoto Univ., >***** Gokasho, Uji, 611-0011, Japan From snoke at vt.edu Thu Apr 30 08:24:54 2009 From: snoke at vt.edu (Arthur Snoke) Date: Thu, 30 Apr 2009 11:24:54 -0400 (EDT) Subject: [SAC-HELP] a polezero question Message-ID: In preparing an update for the polezero section of the transfer help page, I decided to try it (I use polezero files, but not within SAC). I found that the sample given in the current help message does not work, and would appreciate comments from those who have used it (successfully). Also, the documentation claims that the search will look for a polezero file in ${SACHOME}/polezero/. I tried that, but it did not work. The sample given is EXAMPLE: suppose the file was named sro.pz and you want to remove the instrument response from station ABC.Z. u: READ ABC.Z u: TRANSFER FROM POLEZERO SUBTYPE SRO.PZ TO NONE Because the displacement response for any seismometer I have worked with is zero at zero frequencies, the polezero transfer function is zero at zero frequency. Taking out an instrument means dividing by the transfer function in the frequency domain, so the above expression will either blow up or just give an output waveform that is a sinusoid at the fundamental frequency. I got results that compared well with my home-grown method within the passband of interest by using the line transfer from polezero subtype M06C.pz to NONE FREQ 0.001 0.007 0.1 0.2 The seismometer is an STS-2 and is the BHZ channel at 40 sps. I had already used decimate (three times) to reduce the sampling rate to 1 sps. I typically run the equivalent to SAC rtr before doing the instrument correction. Should that be included in the sample? I then moved M06C.pz to my ${SACAUX}/polezero directory, I got the following: SAC> transfer from polezero subtype M06C.pz to NONE FREQ 0.001 0.007 0.1 0.2 ERROR 108: File does not exist: SAC> ls /usr/local/sac/aux/polezero M06C.pz llsn SAC> If it does not work as advertised, we should either remove the polezero subdirectory or make it work. Comments? Arthur Snoke From andy.wuestefeld at bristol.ac.uk Thu Apr 30 13:37:17 2009 From: andy.wuestefeld at bristol.ac.uk (Andreas Wuestefeld) Date: Thu, 30 Apr 2009 21:37:17 +0100 Subject: [SAC-HELP] sac on cygwin - getline problem In-Reply-To: References: Message-ID: <49FA0BFD.5020900@bristol.ac.uk> Dear Masumi I just tried to reconstruct the error you are describing. However, I don't run into any troubles. Which version of SAC and CYGWIN are you using? I am installing SAC-101.2 and on both CYGWIN-1.5.25-15 and the new CYGWIN-1.7beta this installs fine (provided all necesary CYGWIN packages are installed): http://seis.bris.ac.uk/~glxaw/Cygwin4seismology.htm Please let me know whether that helped, and also what other packages you have installed which might cause interferences. Regards Andy -- Dr. Andreas Wuestefeld, Dept. Earth Sciences, Univ. Bristol (UK) http://seis.bris.ac.uk/~glxaw/