Location

2006/04/11 00:02:43 37.74 21.23 20

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=5.5 2006/04/11 00:02:43 EVID: LAT: 37.74N, LON: 21.23E, DEPTH: 20 Mw: 5.5, mb: 0.0, Ms: 0.0 Mo= 0.231E+25 (dyne-cm) No. of Stations: 18, GAP: 89 Error (clvd/dc)*100= 4.98 Bandpass: 12 - 60 sec Nodal plane parameters strike dip rake NP1: 21 86 -109 NP2: 280 19 -12 ############### #################---- #####---------------#------ ###------------------#####----- ##--------------------########--- #---------------------##########--- #---------------------#############-- #----------------------##############-- ----------------------################- ------- -----------#################- ------- P -----------################## ------- ----------################### -------------------#################### ------------------########## ######## -----------------########## T ####### ---------------########### ###### -------------#################### -----------#################### --------################### ----################# ############### Stat Dist Az Misfit Stat Dist Az Misfit AML 39 66 0.38 ARU 31 40 0.55 BILL 71 13 0.97 COLD 75 356 0.99 DBIC 38 224 1.41 EGMT 84 329 1.03 ENH 70 66 0.87 ERPA 72 310 3.48 HIA 67 44 0.56 KURK 42 53 0.44 KZA 41 66 0.64 LSA 57 75 0.99 MA2 74 24 0.89 MSEY 52 135 2.14 PALK 61 103 0.85 TIXI 59 20 0.85 ULN 60 50 0.40 YAK 65 29 0.84 Misfit > 1 heavily downweighted

06/04/11 00:02:43.72 SOUTHERN GREECE Epicenter: 37.739 21.226 MW 5.4 USGS MOMENT TENSOR SOLUTION Depth 10 No. of sta: 14 Moment Tensor; Scale 10**17 Nm Mrr= 0.55 Mtt= 0.51 Mff=-1.06 Mrt= 0.74 Mrf=-1.18 Mtf=-0.24 Principal axes: T Val= 1.68 Plg=48 Azm= 34 N 0.01 27 159 P -1.69 29 266 Best Double Couple:Mo=1.7*10**17 NP1:Strike= 44 Dip=30 Slip= 158 NP2: 154 79 62 ####### -################ ---################## ------################### --------######### #######-- ----------######## T ########-- -----------####### ########-- -------------#################--- ---- ------#################--- ---- P -------###############---- ---- --------##############---- ----------------############----- ----------------##########----- -----------------#######------- -----------------####-------- ------------------------- #---------######----- ################- #######

April 11, 2006, SOUTHERN GREECE, MW=5.5 Natasha Maternovskaya CENTROID, MOMENT TENSOR SOLUTION HARVARD EVENT-FILE NAME C041106A DATA USED: GSN L.P. BODY WAVES: 68S,133C, T= 40 SURFACE WAVES: 77S,151C, T= 50 CENTROID LOCATION: ORIGIN TIME 00:02:46.9 0.2 LAT 37.67N 0.02;LON 20.78E 0.01 DEP 20.2 0.7;HALF-DURATION 1.4 MOMENT TENSOR; SCALE 10**24 D-CM MRR= 1.42 0.04; MTT= 0.20 0.03 MPP=-1.62 0.03; MRT= 0.98 0.07 MRP=-1.17 0.07; MTP= 0.39 0.03 PRINCIPAL AXES: 1.(T) VAL= 2.17;PLG=63;AZM= 30 2.(N) 0.06; 17; 155 3.(P) -2.22; 21; 252 BEST DOUBLE COUPLE:M0=2.2*10**24 NP1:STRIKE= 10;DIP=28;SLIP= 127 NP2:STRIKE=149;DIP=68;SLIP= 72 ##########- -###############--- ---#################--- -----##################---- ------###################---- --------######### #######---- --------######### T #######---- ----------######## ########---- -----------##################---- ------------#################---- -- --------###############----- - P ---------##############---- - -----------###########----- ---------------#########----- ----------------######----- ----------------##----- --------------###-- ------#####

Deviatoric Moment Tensor Solution

The following broadband stations were used for the source inversion: AML ARU BILL COLD DBIC EGMT ENH ERPA HIA KURK KZA LSA MA2 MSEY PALK TIXI ULN YAK

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.)]

All observed and Greens function waveforms are corrected to instrument response to ground velocity in meters/sec for the passband of 0.01 - 5 Hz. Next tre traces were bandpass filtered by the application of the following high- and low-pass stages:

hp c 0.0167 2
lp c 0.0833 2

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   20.0   21.   86. -109.   5.54     0.259 0.967E-07     0.439     0.552 0.535E-07   5.0

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