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Sunday
Aug242014

Northern California, USA - 24 Aug, 2014 - M 6.0

A magnitude 6.0 earthquake occurred in northern California just north of San Francisco Bay this morning. Shaking in the epicentral region is estimated to be Intensity Level Vii (very strong, with the capability to produce moderate damage). 

 

Aftershocks:

Information is still coming in about the earthquake so you can check the latest results at the US Geological Survey site:

http://earthquake.usgs.gov/earthquakes/eventpage/nc72282711#summary

One of the closest easily accessible stations is located in Lucas Valley, about 30 km from the epicenter. The station has a quiet borehole sensor and aftershocks are readily apparent on B057 signals. The channel list:

PB; B057;--; EHZ; B057, LUCAS VALLEY, CA, USA (VERTICAL)
PB; B057;--; EH1; B057, LUCAS VALLEY, CA, USA (NORTH-SOUTH)
PB; B057;--; EH2; B057, LUCAS VALLEY, CA, USA (EAST-WEST)

To monitor aftershocks, use the above channel list and insert an asterisk in the Sample Rate field. To turn the filters off, insert negative numbers into the Low Corner and High Corner fields. The data sample rate is 100 samples per second, so don't use a duration that's too long. I've been using 30 minutes. Here is a plot of some early aftershock activity ("local time" in the seismogram plots is the app-user's local time, eastern time in the samples):

Here is a plot of the mainshock on more distant stations in the San Francisco Bay Area (channel list in popup):

and across the conterminous US (Conterminous US list in Channel-Lists popup menu):