HR: 0800h
AN: S11B-1016    [Abstracts]
TI: Detecting and locating global seismic events using a matched filter on very-long-period seismic data
AU: * Walker, K
EM: walker@ucsd.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Ave., MC 0225, La Jolla, CA 92093-0225 United States
AU: Shearer, P
EM: pshearer@ucsd.edu
AF: Institute of Geophysics and Planetary Physics, Scripps Institution of Oceanography, University of California, San Diego, 9500 Gilman Ave., MC 0225, La Jolla, CA 92093-0225 United States
AB: We apply a series of different matched filters to very-long-period (50 to 500 s) global seismograms of the GSN network from 1975 to 2002 in an effort to detect and locate previously unknown seismic events. These filters are sensitive to longer periods than the techniques routinely used to locate earthquakes, and have the potential to locate events that radiate most of their energy into surface waves: slow earthquakes (such as those along oceanic transform faults), glacial basal slip events (Ekstr\"{o}m et al., 2003), and perhaps avalanches and volcanic events. Such techniques may also compensate for the difficulty in detecting "normal" earthquakes where gaps exist in the broadband networks (e.g., southern oceans). We build on previous results by Shearer (1994) by examining a more complete global set of stations and applying filters that are sensitive to waveform polarity as well as amplitude. We compare the event detection and location capabilities of the different methods and present a list of any previously undetected events. We will estimate magnitudes for these events and compare them with cataloged events from the same regions to better understand the source mechanisms responsible for these very-long-period signals.
DE: 7230 Seismicity and seismotectonics
DE: 7255 Surface waves and free oscillations
DE: 7294 Instruments and techniques
DE: 7215 Earthquake parameters
DE: 1734 Seismology
SC: Seismology [S]
MN: 2004 AGU Fall Meeting