This is a preliminary UCB moment tensor solution for the event centered in Bolinas, CA (37.91N 122.69W; Z=6.9; ML=5.0; USGS/UCB Joint Notification System) on August 18, 1999 at 18:06:18UTC. An average Mw4.7 was obtasined from long-period surface wave spectra and complete long-period waveforms. A depth of 8 km was obtained from long period complete waveforms. This event is a REVERSE mechanism parallel to the San Andreas Fault. Best Fitting Double-Couple: Complete Three-Comp Waveforms Surface Wave Amp and Phase Spectra Mo = 7.25E+22 Dyne-cm 1.6e+23 Mw = 4.54 4.8 Z = 8 km 6 km Plane Strike Rake Dip Strike Rake Dip NP1 115 69 49 121 86 51 NP2 325 112 45 307 95 39 Principal Axes: Axis Value Plunge Azimuth T 7.250 74 317 N 0.000 16 129 P -7.250 2 220 Best regards, Douglas Dreger Hrvoje Tkalcic UC Berkeley Seismological Laboratory Berkeley Moment Tensor Solution Event Date/Time: prel Moment Tensor: Scale = 10**22 Dyne-cm Component Value Mxx -4.003 Mxy -3.828 Mxz 1.574 Myy -2.699 Myz -1.147 Mzz 6.703 ------- ------------------- #####-------------------- #############---------------- ##################--------------- #####################-------------- ########################------------- -##########################------------ --##########################----------- ----############# ##########----------- -----############ T ###########---------- ------########### ############--------- -------##########################-------- ---------########################-------- ----------#######################------ -------------####################------ ----------------################----# ----------------------#######--#### -- ------------------------#### P ------------------------## -----------------------# ------------------- -------