HR: 0830h
AN: S21D-0341    [PDF]
TI: Relative propagation parameters and source locations of similar events using seismic antennas
AU: * Almendros, J
EM: alm@iag.ugr.es
AF: Instituto Andaluz de Geof\'{\i}sica, Universidad de Granada, Granada, 18071 Spain
AU: Carmona, E
EM: ecarmona@iag.ugr.es
AF: Instituto Andaluz de Geof\'{\i}sica, Universidad de Granada, Granada, 18071 Spain
AU: Ib\'a\~nez, J
EM: ibanez@iag.ugr.es
AF: Instituto Andaluz de Geof\'{\i}sica, Universidad de Granada, Granada, 18071 Spain
AB: We introduce a method to accurately determine the relative propagation parameters (apparent slowness and propagation azimuth) of events with similar waveforms recorded on seismic antennas. This relative slowness estimate (RelSE) method is based on precise measurements of the differences among arrival times of different earthquakes to the receivers of the antenna. Delays are determined using interpolations of the cross-correlations of the seismograms. Given the resemblance of waveforms, this method allows for an accuracy higher than the sampling rate. We apply the RelSE method to a multiplet composed of sixteen similar earthquakes recorded during the 1999 seismic crisis at Deception Island volcano, Antarctica. Relative apparent slowness vectors are determined for the P-wave onset. Results show that the slowness vectors are closely distributed in a narrow, north-south trending band on the apparent slowness space centered at about 0.27 s/km and 245$\deg$N. We estimate the source locations of these events using the S-P delays and an inverse ray-tracing procedure through a velocity model. The obtained solutions define two plane structures that can be regarded as the fractures originating the recorded earthquakes. We conclude that the RelSE method, combined with other source location techniques, may be very useful for the analysis of microearthquake series recorded on seismic antennas. Furthermore, it is well suited for the analysis of long-period seismicity in the field of volcano seismology.
DE: 7215 Earthquake parameters
DE: 7230 Seismicity and seismotectonics
DE: 7280 Volcano seismology (8419)
SC: Seismology [S]
MN: 2003 Fall Meeting