Location

2006/02/02 12:48:43 -17.67 -178.37 595

Moment Tensor Comparison

The following compares this source inversion to the USGS Rapid Moment Tensor Solution and to the Harvard CMT solutions, if they are available.

Mw=6.8 2006/02/02 12:48:43 EVID: LAT: 17.67S, LON: 178.37W, DEPTH: 610 Mw: 6.8, mb: 0.0, Ms: 0.0 Mo= 0.150E+27 (dyne-cm) No. of Stations: 146, GAP: 76 Error (clvd/dc)*100= 35.07 Nodal plane parameters strike dip rake NP1: 13 64 -126 NP2: 253 43 -39 ########## ################---- ###################------- ######################-------- #######################--------- ############------------######---- #########----------------#########-- #######-------------------############ #####---------------------############ #####----------------------############# ###------------------------############# ##------------------------############## ##------------------------############## ------------------------############## ------------------------############## ----------------------############## --------------------############## ------------------############## ----------------############## -------------############# --------############ -######### Stat Dist Az Misfit Stat Dist Az Misfit 109C 77 49 0.36 ADK 69 1 0.42 ARMA 30 239 36.24 BAK 77 46 0.30 BAR 77 49 0.27 BBOO 43 240 0.47 BBR 77 48 0.29 BC3 78 49 0.33 BDM 76 42 0.34 BEL 78 48 0.39 BFS 77 47 0.34 BLDU 59 244 0.29 BVDA 77 49 0.80 BZN 77 48 0.40 CASY 66 204 0.18 CHF 77 47 0.31 CIA 76 48 0.27 CMB 77 43 0.34 COCO 81 259 0.18 COEN 37 270 1.71 CRY 77 48 0.38 CTAO 33 260 0.24 CVS 76 42 0.35 CWC 78 45 0.34 DAN 79 48 0.38 DAV 60 289 1.25 DBO 78 37 0.47 DEC 76 47 0.27 DGR 77 48 0.33 DJJ 76 47 0.37 DVT 77 49 0.91 EUO 79 37 0.94 FARB 75 42 0.66 FMP 76 47 0.31 FRD 77 48 0.31 FUR 79 46 0.41 G04A 80 36 0.37 G05A 81 36 0.37 GASB 77 40 0.34 GLA 78 50 0.26 GRA 79 45 0.32 GSC 78 47 0.40 GUMO 47 308 0.47 H03A 79 36 0.37 H04A 80 36 0.36 HAST 75 44 0.27 HATC 78 40 0.45 HEC 78 47 0.43 HELL 77 45 0.38 HOPS 76 41 0.28 HUMO 78 38 0.31 HWB 77 49 0.93 I02A 79 36 0.39 I03A 79 37 0.34 I05A 80 37 0.36 IRM 79 48 0.31 ISA 77 46 0.30 JCS 77 49 0.35 JRO 81 35 0.97 JRSC 76 42 0.66 KCC 77 44 0.32 KKM 68 283 0.26 KMBL 55 243 1.63 KNW 77 48 0.31 KSM 72 277 0.21 KUM 83 277 0.20 LAVA 77 42 0.36 LGU 76 47 0.43 LRL 78 46 0.28 LTH 82 36 0.34 LVA2 77 49 0.31 M02C 78 39 0.45 M03C 78 39 0.33 M04C 78 39 0.43 M05C 79 40 0.41 M06C 79 40 0.30 MAJO 67 323 0.38 MAUI 43 30 0.52 MBWA 58 255 0.22 MLAC 78 44 0.97 MNRC 76 41 0.34 MOD 79 40 0.34 MONP 77 49 0.33 MPP 76 46 0.35 MUR 77 48 0.41 MWC 77 47 0.26 NACB 71 303 0.36 NWAO 59 241 0.21 O01C 76 39 0.28 O03C 77 40 0.38 O04C 78 41 0.33 O05C 78 41 0.31 ORV 77 41 0.37 OSI 76 46 0.24 P01C 76 40 0.26 P05C 78 42 0.32 PACP 76 43 0.25 PAS 77 47 0.28 PDM 79 49 0.35 PET 73 345 0.49 PFO 77 48 0.32 PHL 76 45 0.25 PIN 80 38 0.88 PKD 76 44 0.25 PLM 77 48 0.32 PMG 34 279 0.41 POHA 43 32 0.45 PPUH 82 37 0.99 PTCN 45 107 0.27 Q03C 76 42 0.28 Q04C 77 42 0.34 R04C 77 42 0.35 R07C 78 43 0.37 RCT 77 45 0.34 RDM 77 48 0.35 RPV 76 47 0.30 S04C 76 43 0.28 S05C 77 43 0.31 S06C 77 43 0.37 SBA 60 183 0.29 SMER 77 48 0.36 SND 77 48 0.30 SOL 77 49 0.26 STD 81 35 0.93 SUTB 77 41 0.30 T05C 76 44 0.31 T06C 77 44 0.39 TATO 72 304 0.43 TOO 37 230 10.15 TRO 77 48 0.34 U04C 76 44 0.27 U05C 76 44 0.30 V03C 75 44 0.31 V04C 75 45 0.32 V05C 76 45 0.33 WDC 77 40 0.41 WENL 76 42 0.49 WIFE 80 37 1.02 WMC 77 48 0.55 WRAB 44 259 0.34 Y12C 79 49 0.29 Y22C 85 52 0.37 YBH 78 39 0.32 YHNB 72 303 0.45 YNG 33 234 0.29 YULB 71 302 0.26 Misfit > 1 heavily downweighted

Mw=6.6 FIJI REGION 2006/02/02 12:48:43.69 EVID: IRAM LAT: 17.67S, LON: 178.37W, DEPTH: 600 Mw: 6.6, mb: 6.6, Ms: 6.6 Mo= 0.103E+27 (dyne-cm) No. of Stations: 25, GAP: 95 Error (clvd/dc)*100= 8.37 Nodal plane parameters strike dip rake NP1: 18 63 238 NP2: 252 41 -44 ########## #################--- ####################------ #######################------- ###############---------#------- ###########--------------######--- ########------------------#########- #######--------------------########### #####----------------------########### #####-----------------------############ ###------------------------############# ##-------------------------############# ##------------------------############## ------------------------############## ------------------------############## ----------------------############## --------------------############## ------------------############## ---------------############### ------------############## -------############# ########## Stat Dist Az Misfit Stat Dist Az Misfit ADK 69 1 0.26 ANMO 85 51 0.46 BW06 87 43 0.52 CMB 77 43 0.39 COCO 81 259 0.25 COLA 85 12 0.37 COR 79 36 0.30 CTAO 33 260 0.33 GUMO 47 308 0.43 HKT 92 59 0.49 INCN 75 317 0.26 KWAJ 29 331 0.86 MA2 80 344 0.14 MAJO 67 323 0.25 MOD 79 40 0.31 MSO 86 38 0.60 NWAO 59 241 0.14 PAYG 87 90 0.74 PET 73 345 0.38 TUC 81 52 0.42 ULN 92 319 0.25 VNDA 60 184 0.54 WDC 77 40 0.48 YAK 89 338 0.24 YSS 73 333 0.33 Median of misfit: 0.37 Average misfit: 0.39

February 2, 2006, FIJI REGION, MW=6.7 Natasha Maternovskaya CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C020206A DATA USED: GSN L.P. BODY WAVES: 37S, 95C, T= 50 MANTLE WAVES: 31S, 71C, T=125 CENTROID LOCATION: ORIGIN TIME 12:48:48.5 0.1 LAT 17.76S 0.01;LON 178.19W 0.01 DEP 609.1 1.1;HALF-DURATION 5.5 MOMENT TENSOR; SCALE 10**26 D-CM MRR=-0.88 0.01; MTT= 0.10 0.02 MPP= 0.78 0.02; MRT= 0.14 0.02 MRP=-0.90 0.02; MTP= 0.78 0.02 PRINCIPAL AXES: 1.(T) VAL= 1.50;PLG=17;AZM=118 2.(N) -0.08; 27; 18 3.(P) -1.42; 57; 236 BEST DOUBLE COUPLE:M0=1.5*10**26 NP1:STRIKE=242;DIP=37;SLIP= -40 NP2:STRIKE= 6;DIP=67;SLIP=-120 ########--- #############------ ###############-------- ##########--------######--- ########-----------#########- #######-------------########### #####---------------########### ####-----------------############ ###------------------############ ###------------------############ ##-------- --------############ #-------- P -------####### ## #-------- -------####### T ## -----------------######## # ----------------########### -------------########## ----------######### -----######

Deviatoric Moment Tensor Solution

The following broadband stations were used for the source inversion: 109C ADK ARMA BAK BAR BBOO BBR BC3 BDM BEL BFS BLDU BVDA2 BZN CASY CHF CIA CMB COCO COEN CRY CTAO CVS CWC DAN DAV DBO DEC DGR DJJ DVT EUO FARB FMP FRD FUR G04A G05A GASB GLA GRA GSC GUMO H03A H04A HAST HATC HEC HELL HOPS HUMO HWB I02A I03A I05A IRM ISA JCS JRO JRSC KCC KKM KMBL KNW KSM KUM LAVA LGU LRL LTH LVA2 M02C M03C M04C M05C M06C MAJO MAUI MBWA MLAC MNRC MOD MONP MPP MUR MWC NACB NWAO O01C O03C O04C O05C ORV OSI P01C P05C PACP PAS PDM PET PFO PHL PIN PKD PLM PMG POHA PPUHS PTCN Q03C Q04C R04C R07C RCT RDM RPV S04C S05C S06C SBA SMER SND SOL STD SUTB T05C T06C TATO TOO TRO U04C U05C V03C V04C V05C WDC WENL WIFE WMC WRAB Y12C Y22C YBH YHNB YNG YULB

Location of the earthquake (yellow star) and great circle path from the epicenter to each station (red) [created using GMT (Wessel, P., and W. H. F. Smith, New version of Generic Mapping Tools released, EOS Trans. AGU, 76 329, 1995.)]

The traces were next integrated to ground displacment in meters. Finally waveforms were cut from 30 seconds before to 140 seconds after the P arrival so that the direct P wave, pP and perhaps the sP are included.

The source inversion is a multipass operation since a lower frequency filter band is used for larger earthquakes and since a search is made over depth. Up to three passed of the outer loop are made, after which the moment magnitude is determined and filter settings readjusted. The inner loop over depth samples all depths from 0 to 800 km with 5 km increments in depth to 50 km, followed by 10 km depth sampling for the remaining range.

The following filter ranges are used according to the moment magnitude Mw:

   FILTER_BAND   FH(s)  FL(s)
       1           60     12      Mw < 6.4
       2          100     20      6.4 < Mw <= 6.9
       3          120     40      Mw > 6.9

For this data set the favored solution is

WVFMTD96  610.0   13.   64. -126.   6.77     0.176 0.162E-05     0.498     0.442 0.760E-06  35.1

The following figures show the sensitivity of the goodness of fit parameter so source depth, the waveform comparison as a function of epicentral distance in degrees and the source to station azimuth

Depth Sensitivity

Goodness of fit as a function of source depth. The measure is 1 - SUM (o -p)2 / SUM o2. A value of 1.0 is the best fit. The best double couple mechanism for the solution depth is plotted above goodness of fit value to indicate how the mefhanism may change with depth.

Fit with Distance

Fit with Azimuth

Comparison of the observed traces (red) and solution predicted traces (blue) as a function of source to station azimuth in degrees (D). The purpose of this display is to highlight the azimuthal dependence on the first motion. The traces are annotated with the station name at the top.

Inversion Details