Catalog Mag Time Depth Review Status Location Source CI 6.4 mw 17:33:49 10.7 km REVIEWED 35.705°N 117.506°W CI 2 NN 6.2 ml 17:33:48 11.2 km REVIEWED 35.679°N 117.516°W NN 3 US 6.5 mww 17:33:48 8.7 km REVIEWED 35.705°N 117.508°W US 5 CI 2 PT 6.5 Mi 17:33:48 2.0 km REVIEWED 35.600°N 117.400°W PT 4 Magnitudes Mw Mag Err Stations Source 6.4 ----- 6 CI 2 Ml 6.47 0.159 291 CI 2 Mlr 5.37 0.416 15 CI 2 Me 6.6 0.302 99 CI 2 Mww 6.5 0.037 70 US Mwr 6.4 ----- 6 CI 2 ML 5.8 0.416 15 CI 2
USGS/SLU Moment Tensor Solution ENS 2019/07/04 17:33:49:0 35.71 -117.51 8.7 6.4 California Stations used: AE.113A AE.BARN AE.PRCT AE.W13A AE.X16A AE.Y14A AZ.CPE BC.SFX BC.SJX BC.TJX BC.TKX BC.VTX BK.BUCR BK.MNRC BK.MTOS BK.PACP BK.WELL BK.WINE CI.BLY CI.CCA CI.ELS2 CI.GLA CI.GRA CI.GSC CI.ISA CI.LDF CI.PASC CI.RAG CI.YUH2 II.PFO IM.NV31 LB.MVU LB.TPH NC.AFD NN.DSP NN.GMN NN.GWY NN.LHV NN.MPK NN.MZPB NN.PAH NN.PIO NN.PRN NN.Q09A NN.QSM NN.R11B NN.RYN NN.S11A NN.SHP NN.SPR3 NN.V12A NN.WAK NN.WDEM NN.WLDB SN.HEL US.ELK US.TPNV US.WUAZ UU.CCUT UU.KNB UU.LCMT UU.PSUT UU.SZCU UU.VRUT Filtering commands used: cut o DIST/3.3 -40 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.05 n 3 Best Fitting Double Couple Mo = 2.60e+25 dyne-cm Mw = 6.21 Z = 14 km Plane Strike Dip Rake NP1 40 85 -20 NP2 132 70 -175 Principal Axes: Axis Value Plunge Azimuth T 2.60e+25 10 88 N 0.00e+00 69 207 P -2.60e+25 18 354 Moment Tensor: (dyne-cm) Component Value Mxx -2.33e+25 Mxy 3.47e+24 Mxz -7.26e+24 Myy 2.49e+25 Myz 5.34e+24 Mzz -1.54e+24 ---- ------- -------- P ----------- ----------- -------------# ---------------------------### ##--------------------------###### ####------------------------######## ######---------------------########### ########-------------------############# #########----------------############### ###########--------------############# # #############----------############### T # ###############-------################ # #################---###################### ######################################## ################----#################### #############--------################# ###########------------############# ########------------------######## ####-------------------------- #--------------------------- ---------------------- -------------- Global CMT Convention Moment Tensor: R T P -1.54e+24 -7.26e+24 -5.34e+24 -7.26e+24 -2.33e+25 -3.47e+24 -5.34e+24 -3.47e+24 2.49e+25 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20190704173349/index.html |
STK = 40 DIP = 85 RAKE = -20 MW = 6.21 HS = 14.0
The NDK file is 20190704173349.ndk The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution ENS 2019/07/04 17:33:49:0 35.71 -117.51 8.7 6.4 California Stations used: AE.113A AE.BARN AE.PRCT AE.W13A AE.X16A AE.Y14A AZ.CPE BC.SFX BC.SJX BC.TJX BC.TKX BC.VTX BK.BUCR BK.MNRC BK.MTOS BK.PACP BK.WELL BK.WINE CI.BLY CI.CCA CI.ELS2 CI.GLA CI.GRA CI.GSC CI.ISA CI.LDF CI.PASC CI.RAG CI.YUH2 II.PFO IM.NV31 LB.MVU LB.TPH NC.AFD NN.DSP NN.GMN NN.GWY NN.LHV NN.MPK NN.MZPB NN.PAH NN.PIO NN.PRN NN.Q09A NN.QSM NN.R11B NN.RYN NN.S11A NN.SHP NN.SPR3 NN.V12A NN.WAK NN.WDEM NN.WLDB SN.HEL US.ELK US.TPNV US.WUAZ UU.CCUT UU.KNB UU.LCMT UU.PSUT UU.SZCU UU.VRUT Filtering commands used: cut o DIST/3.3 -40 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.05 n 3 Best Fitting Double Couple Mo = 2.60e+25 dyne-cm Mw = 6.21 Z = 14 km Plane Strike Dip Rake NP1 40 85 -20 NP2 132 70 -175 Principal Axes: Axis Value Plunge Azimuth T 2.60e+25 10 88 N 0.00e+00 69 207 P -2.60e+25 18 354 Moment Tensor: (dyne-cm) Component Value Mxx -2.33e+25 Mxy 3.47e+24 Mxz -7.26e+24 Myy 2.49e+25 Myz 5.34e+24 Mzz -1.54e+24 ---- ------- -------- P ----------- ----------- -------------# ---------------------------### ##--------------------------###### ####------------------------######## ######---------------------########### ########-------------------############# #########----------------############### ###########--------------############# # #############----------############### T # ###############-------################ # #################---###################### ######################################## ################----#################### #############--------################# ###########------------############# ########------------------######## ####-------------------------- #--------------------------- ---------------------- -------------- Global CMT Convention Moment Tensor: R T P -1.54e+24 -7.26e+24 -5.34e+24 -7.26e+24 -2.33e+25 -3.47e+24 -5.34e+24 -3.47e+24 2.49e+25 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20190704173349/index.html |
Moment Tensor (TMTS) Moment 4.918e+18 N-m Magnitude 6.39 Depth 8.0 km Percent DC 74% Half Duration - Catalog CI Data Source CI 2 Contributor CI 2 Nodal Planes Plane Strike Dip Rake NP1 228Â 66Â 4Â NP2 137Â 86Â 156Â Principal Axes Axis Value Plunge Azimuth T 4.545e+18 N-m 20Â 90Â N 0.676e+18 N-m 65Â 308Â P -5.221e+18 N-m 14Â 185Â |
W-phase Moment Tensor (Mw) Moment 6.155e+18 N-m Magnitude 6.46 Mww Depth 11.5 km Percent DC 95% Half Duration 4.44 s Catalog US Data Source US 4 Contributor US 4 Nodal Planes Plane Strike Dip Rake NP1 229Â 77Â 3Â NP2 139Â 87Â 167Â Principal Axes Axis Value Plunge Azimuth T 6.235e+18 N-m 11Â 93Â N -0.163e+18 N-m 76Â 308Â P -6.072e+18 N-m 8Â 185Â |
(a) mLg computed using the IASPEI formula; (b) mLg residuals ; the values used for the trimmed mean are indicated.
(a) ML computed using the IASPEI formula for Horizontal components; (b) ML residuals computed using a modified IASPEI formula that accounts for path specific attenuation; the values used for the trimmed mean are indicated. The ML relation used for each figure is given at the bottom of each plot.
(a) ML computed using the IASPEI formula for Vertical components (research); (b) ML residuals computed using a modified IASPEI formula that accounts for path specific attenuation; the values used for the trimmed mean are indicated. The ML relation used for each figure is given at the bottom of each plot.
The focal mechanism was determined using broadband seismic waveforms. The location of the event and the and stations used for the waveform inversion are shown in the next figure.
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The program wvfgrd96 was used with good traces observed at short distance to determine the focal mechanism, depth and seismic moment. This technique requires a high quality signal and well determined velocity model for the Green functions. To the extent that these are the quality data, this type of mechanism should be preferred over the radiation pattern technique which requires the separate step of defining the pressure and tension quadrants and the correct strike.
The observed and predicted traces are filtered using the following gsac commands:
cut o DIST/3.3 -40 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.05 n 3The results of this grid search from 0.5 to 19 km depth are as follow:
DEPTH STK DIP RAKE MW FIT WVFGRD96 1.0 225 90 5 5.87 0.2892 WVFGRD96 2.0 45 85 -10 5.97 0.3705 WVFGRD96 3.0 225 90 5 6.01 0.4073 WVFGRD96 4.0 225 90 5 6.04 0.4320 WVFGRD96 5.0 45 90 0 6.07 0.4496 WVFGRD96 6.0 45 90 -5 6.09 0.4639 WVFGRD96 7.0 225 90 5 6.11 0.4771 WVFGRD96 8.0 45 85 -10 6.14 0.4902 WVFGRD96 9.0 45 85 -10 6.15 0.4920 WVFGRD96 10.0 45 85 -15 6.17 0.4926 WVFGRD96 11.0 45 85 -15 6.18 0.4933 WVFGRD96 12.0 225 90 20 6.19 0.4927 WVFGRD96 13.0 220 90 20 6.20 0.4933 WVFGRD96 14.0 40 85 -20 6.21 0.4967 WVFGRD96 15.0 220 80 20 6.22 0.4943 WVFGRD96 16.0 220 80 20 6.23 0.4944 WVFGRD96 17.0 220 80 20 6.23 0.4939 WVFGRD96 18.0 220 80 20 6.24 0.4926 WVFGRD96 19.0 220 80 20 6.25 0.4907 WVFGRD96 20.0 220 80 20 6.25 0.4883 WVFGRD96 21.0 220 80 20 6.26 0.4855 WVFGRD96 22.0 220 80 20 6.27 0.4820 WVFGRD96 23.0 220 80 20 6.27 0.4781 WVFGRD96 24.0 220 80 20 6.28 0.4739 WVFGRD96 25.0 220 80 20 6.29 0.4693 WVFGRD96 26.0 220 80 20 6.29 0.4645 WVFGRD96 27.0 220 80 20 6.30 0.4595 WVFGRD96 28.0 40 85 -20 6.30 0.4550 WVFGRD96 29.0 40 85 -20 6.31 0.4508
The best solution is
WVFGRD96 14.0 40 85 -20 6.21 0.4967
The mechanism correspond to the best fit is
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The best fit as a function of depth is given in the following figure:
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The comparison of the observed and predicted waveforms is given in the next figure. The red traces are the observed and the blue are the predicted. Each observed-predicted component is plotted to the same scale and peak amplitudes are indicated by the numbers to the left of each trace. A pair of numbers is given in black at the right of each predicted traces. The upper number it the time shift required for maximum correlation between the observed and predicted traces. This time shift is required because the synthetics are not computed at exactly the same distance as the observed and because the velocity model used in the predictions may not be perfect. A positive time shift indicates that the prediction is too fast and should be delayed to match the observed trace (shift to the right in this figure). A negative value indicates that the prediction is too slow. The lower number gives the percentage of variance reduction to characterize the individual goodness of fit (100% indicates a perfect fit).
The bandpass filter used in the processing and for the display was
cut o DIST/3.3 -40 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.05 n 3
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Focal mechanism sensitivity at the preferred depth. The red color indicates a very good fit to thewavefroms. Each solution is plotted as a vector at a given value of strike and dip with the angle of the vector representing the rake angle, measured, with respect to the upward vertical (N) in the figure. |
A check on the assumed source location is possible by looking at the time shifts between the observed and predicted traces. The time shifts for waveform matching arise for several reasons:
Time_shift = A + B cos Azimuth + C Sin Azimuth
The time shifts for this inversion lead to the next figure:
The derived shift in origin time and epicentral coordinates are given at the bottom of the figure.
Thanks also to the many seismic network operators whose dedication make this effort possible: University of Nevada Reno, University of Alaska, University of Washington, Oregon State University, University of Utah, Montana Bureas of Mines, UC Berkely, Caltech, UC San Diego, Saint Louis University, University of Memphis, Lamont Doherty Earth Observatory, the Iris stations and the Transportable Array of EarthScope.
The WUS.model used for the waveform synthetic seismograms and for the surface wave eigenfunctions and dispersion is as follows:
MODEL.01 Model after 8 iterations ISOTROPIC KGS FLAT EARTH 1-D CONSTANT VELOCITY LINE08 LINE09 LINE10 LINE11 H(KM) VP(KM/S) VS(KM/S) RHO(GM/CC) QP QS ETAP ETAS FREFP FREFS 1.9000 3.4065 2.0089 2.2150 0.302E-02 0.679E-02 0.00 0.00 1.00 1.00 6.1000 5.5445 3.2953 2.6089 0.349E-02 0.784E-02 0.00 0.00 1.00 1.00 13.0000 6.2708 3.7396 2.7812 0.212E-02 0.476E-02 0.00 0.00 1.00 1.00 19.0000 6.4075 3.7680 2.8223 0.111E-02 0.249E-02 0.00 0.00 1.00 1.00 0.0000 7.9000 4.6200 3.2760 0.164E-10 0.370E-10 0.00 0.00 1.00 1.00
Here we tabulate the reasons for not using certain digital data sets
The following stations did not have a valid response files: