M 7.7 - 133 km NE of Hihifo, Tonga

FELT (VI) AT APIA, SAMOA ISLANDS. LOCAL TSUNAMI (24 CM. PEAK-TO-TROUGH) RECORDED AT PAGO PAGO.!!!!!!!!!!!!!!!!!!!!!!!!!!MANTLE WAVE MOMENT SOLUTION:!!! !!M0=3.3*10**27!!!!!!!MW=7.6!!! FAULT PLANE SOLUTION:!!!!!!!!!! THE PREFERRED FAULT PLANE SOLUTION FROM P-WAVE FIRST MOTIONS CORRESPONDS TO A NORMAL FAULT TYPE MECHANISM. THE FAIRLY WELL CONTROLLED FAULT PLANE STRIKES S 78` E AND DIPS 70` SSW. THE POORLY CONTROLLED AUXILIARY PLANE STRIKES N 78` W AND DIPS 20` NNE. THE P-AXIS PLUNGES 65.0` TOWARD AZIMUTH 12.0` AND THE T-AXIS PLUNGES 25.0` TOWARD AZIMUTH 192.0`.!!! USGS MOMENT TENSOR SOLUTION:!!! !!DATA: UNFILTERED L.P. GDSN!!! !!BODY WAVES!!!!!!!!!!!!!!!!!!! !!CONSTRAINTS: ZERO TRACE!!!!!! !!NO. OF STA: 6!!!DEPTH: 22 KM! !!PRINCIPAL AXES:!!!!!!!!!!!!!! !!!!!!!!!!!VAL!!!!!AZ!!!!PLG!!! !!!!!(10**22 D-CM)!!!!!!!!!!!!! !!!!P!!!!-1.69!!!!182!!!!!63!!! !!!!T!!!!!1.83!!!!!!8!!!!!27!!! !!!!N!!!!-0.15!!!!277!!!!!!2!!! !!BEST DOUBLE COUPLE:!!!!!!!!!! !!!!M0=1.8*10**27 D-CM!!!!!!!!! !!!!!!!!!STRIKE!!!DIP!!!SLIP!!! !!!!NP1!!!!104!!!!!18!!!!277!!! !!!!NP2!!!!276!!!!!72!!!!268!!! CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C090181B DATA USED: GDSN L.P. BODY WAVES: 12S, 36C, T=45 MANTLE WAVES: 14S, 40C, T=135 CENTROID LOCATION: ORIGIN TIME 9:29:47.4 0.2 LAT 15.02S 0.01;LON 173.16W 0.02 DEP 20.0 FIX;HALF-DURATION 20.0 MOMENT TENSOR; SCALE 10**27 D-CM MRR=-1.73 0.02; MTT=1.78 0.02 MFF=-0.05 0.02; MRT=0.65 0.07 MRF=0.18 0.06; MTF=-0.48 0.02 PRINCIPAL AXES: 1.(T) VAL=1.99;PLG=9;AZM=12 2.(N) -0.11; 10; 281 3.(P) -1.88; 76; 143 BEST DOUBLE COUPLE:M0=1.9*10**27 NP1:STRIKE=115;DIP=37;SLIP=-73 NP2:Strike=273;Dip=55;Slip=-103