This is a preliminary UCB moment tensor solution for the event 5 km ESE of
Richmond, CA (37.9220 N, 122.2885 W; Z=5.8km; ML=4.1; USGS/UCB Joint
Notification System) on December 4, 1998 at 12:16:07UTC. An average Mw4.0
and source depth of 11 km were obtained from long-period complete waves and
surface wave amplitude and phase spectra.
Best Fitting Double-Couple:
Complete Waveforms Surface Waves
Mo = 9.26E+21 Dyne-cm 2.10e+22
Mw = 3.94 4.18
Z = 11km
Plane Strike Rake Dip Strike Rake Dip
NP1 231 21 84 228 -8 90
NP2 139 174 69 318 -180 82
Principal Axes:
Axis Value Plunge Azimuth
T 9.260 19 97
N 0.000 68 245
P -9.260 11 3
Best regards,
Douglas Dreger
Hrvoje Tkalcic
UCB Seismological Laboratory
Berkeley Moment Tensor Solution (COMPLETE WAVEFORMS)
Event Date/Time: prel
Moment Tensor: Scale = 10**21 Dyne-cm
Component Value
Mxx -8.793
Mxy -1.517
Mxz -2.019
Myy 8.145
Myz 2.708
Mzz 0.648
--- -
--------- P -------
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#########------------------############
##########---------------##############
############-----------##################
#############--------####################
##############----################# ###
################################### T ###
##############---################## ###
###########-------#####################
#########-----------###################
######---------------################
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Lower Hemisphere Equiangle Projection