HR: 08:20h
AN: S51D-02 [Abstracts]
TI: Use of coda wave interferometry for estimating the variation in source orientation between double couples
AU: * Robinson, D J
EM: david.robinson@anu.edu.au
AF: Research School of Earth Sciences, The Australian National University, Canberra, ACT
0200, Austria
AU: * Robinson, D J
EM: david.robinson@anu.edu.au
AF: Risk Research Group, Geoscience Australia
GPO Box 378, Canberra, ACT 2601, Austria
AU: Snieder, R
AF: Center for Wave Phenomena and Department of Geophysics, Colorado School of Mines,
Golden, CO 80401, United States
AU: Sambridge, M
EM: malcolm.sambridge@anu.edu.au
AF: Research School of Earth Sciences, The Australian National University, Canberra, ACT
0200, Austria
AB:
It is shown how a change in source orientation between two
identically located double couple events can be estimated from the
correlation of their coda waves. The change in orientation
is given by the root mean square of the change in strike,
Δφs dip, Δδ and rake, Δλ of the
double couple. It is not possible to determine Δφs,
Δδ or Δλ individually
from the cross correlation.
Theoretical results are tested using
synthetically generated waveforms for source-pairs with differing strike,
dip and rake. In each case a cross-over
is identified such that the actual change in orientation
is within one standard deviation
of the coda wave interferometry (CWI) estimates for all rotations
below the cross-over. After the cross-over, the CWI
estimates provide a lower bound on the change in orientation. Cross-over
points of 30°, 62° and 56°, respectively
are observed when the strike, dip and rake are varied independently.
When all angles are varied simultaneously by the same quantity
the cross-over point is 17°. The new theory can be applied in combination
with existing coda wave interferometry techniques for estimating source
separation It also has potential
for joint relative location and focal mechanism determination using coda
waves recorded at a single station.
DE: 0669 Scattering and diffraction
DE: 0935 Seismic methods (3025, 7294)
DE: 7215 Earthquake source observations (1240)
DE: 7230 Seismicity and tectonics (1207, 1217, 1240, 1242)
SC: Seismology [S]
MN: 2007 Fall Meeting