[SIO GP Seminars] Reminder: GP Seminar Today at 3:15

[Leah Ziegler]

Geophysics Seminar Fans -

Please join us this afternoon for this week's Geophysics Seminar.   
Please note the small CHANGE IN MEETING TIME from 3 to 3:15.


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Friday, October 6, 3:15 PM
   (refreshments served at 3:00 PM)
   Munk Conference Room

Elizabeth Cochran

   "Infrasound events detected with the Southern California Seismic  
Network"

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ABSTRACT
We examine continuous data from the Southern California Seismic  
Network from 2003 and identify infrasound acoustic waves from 76  
previously undetected events. Using waveform cross-correlation of the  
signal envelope functions, we determine their relative arrival times  
and estimate source locations. The waves travel at acoustic speeds of  
~320 m/s and are observed in seismic records up to 450 km from their  
probable source locations off the west coast of southern California.  
The dominant daylight occurrence of the events points to a man-made  
source related to military activity. The events are mostly recorded  
in the winter and spring when atmospheric conditions trap acoustic  
energy near the Earth's surface and favor propagation to the west.  
These results suggest that data from regional and global seismic  
networks can supplement observations from infrasound arrays for  
Comprehensive Test Ban Treaty monitoring and geophysical applications  
such as volcano monitoring, bolide detection, atmospheric acoustic  
sources and tomography.

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