[irised] Today's 7.7 in Chile

[John Lahr]

>I don't think I have my seismograph calibrated correctly.  Most of 
>the time I have tiny little movement up and down, so it looks like 
>the lines are kind of fuzzy.  In Kansas, on a concrete floor, this 
>probably makes sense.  But when I extract part of a line to look 
>more closely, the peaks and valleys are square, not pointed.  This 
>doesn't make sense to me.  Sometimes it appears that there is no 
>movement at all, and when a segment is extracted it shows wider squares.
>
>Also, I think I should probably have had some record of the 7.7 
>event in Chile today, but there is absolutely no change in the line.
>
>What have I done or not done?


If you didn't record the M7.7 earthquake in Chile, then there is 
certainly something seriously wrong with your seismic station!  One 
way to determine this is to look at the various stations that are 
sending a helicorder image to the web every 10 minutes.  See:
http://jclahr.com/science/psn/as1/heli/allas1.php

Here's the record from Cedar Rapids, Iowa, for example:
Emacs!


A good place to start if you didn't record the event is the FAQ page:
http://jclahr.com/science/psn/as1/faq/

Two common problems are mis-adjustment of the knob on the black box 
and contact, even slight, between the magnet and the coil.

Keep me posted on progress.

Cheers,
John

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