2013/08/27 00:51:43 39.669l -119.684 13.9 4.2 Nevada
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution ENS 2013/08/27 00:51:43:0 39.67 0.00 0.0 0.0 Nevada Stations used: CI.GSC CI.ISA NC.AFD NC.KBO NC.KHMB NC.KMR NC.KRMB NC.MDPB NN.BEK NN.KVN NN.OMMB NN.PAH NN.PNT NN.RUB NN.RYN NN.VCN NN.WAK TA.R11A UU.BGU UU.CCUT UU.PSUT UW.BLOW UW.IRON Filtering commands used: cut a -30 a 180 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.06 n 3 Best Fitting Double Couple Mo = 2.11e+22 dyne-cm Mw = 4.15 Z = 13 km Plane Strike Dip Rake NP1 314 85 170 NP2 45 80 5 Principal Axes: Axis Value Plunge Azimuth T 2.11e+22 11 269 N 0.00e+00 79 108 P -2.11e+22 4 360 Moment Tensor: (dyne-cm) Component Value Mxx -2.10e+22 Mxy 3.15e+20 Mxz -1.36e+21 Myy 2.04e+22 Myz -3.81e+21 Mzz 6.30e+20 ----- P ------ --------- ---------- ---------------------------- #----------------------------# #####-------------------------#### #########---------------------###### ############------------------######## ###############--------------########### #################-----------############ ####################-------############### # ##################---################# # T ###################################### # ##################----################ ###################-------############## #################-----------############ ##############---------------######### ##########-------------------####### #######-----------------------#### ##---------------------------# ---------------------------- ---------------------- -------------- Global CMT Convention Moment Tensor: R T P 6.30e+20 -1.36e+21 3.81e+21 -1.36e+21 -2.10e+22 -3.15e+20 3.81e+21 -3.15e+20 2.04e+22 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20130827005143/index.html |
STK = 45 DIP = 80 RAKE = 5 MW = 4.15 HS = 13.0
The NDK file is 20130827005143.ndk The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution ENS 2013/08/27 00:51:43:0 39.67 0.00 0.0 0.0 Nevada Stations used: CI.GSC CI.ISA NC.AFD NC.KBO NC.KHMB NC.KMR NC.KRMB NC.MDPB NN.BEK NN.KVN NN.OMMB NN.PAH NN.PNT NN.RUB NN.RYN NN.VCN NN.WAK TA.R11A UU.BGU UU.CCUT UU.PSUT UW.BLOW UW.IRON Filtering commands used: cut a -30 a 180 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.06 n 3 Best Fitting Double Couple Mo = 2.11e+22 dyne-cm Mw = 4.15 Z = 13 km Plane Strike Dip Rake NP1 314 85 170 NP2 45 80 5 Principal Axes: Axis Value Plunge Azimuth T 2.11e+22 11 269 N 0.00e+00 79 108 P -2.11e+22 4 360 Moment Tensor: (dyne-cm) Component Value Mxx -2.10e+22 Mxy 3.15e+20 Mxz -1.36e+21 Myy 2.04e+22 Myz -3.81e+21 Mzz 6.30e+20 ----- P ------ --------- ---------- ---------------------------- #----------------------------# #####-------------------------#### #########---------------------###### ############------------------######## ###############--------------########### #################-----------############ ####################-------############### # ##################---################# # T ###################################### # ##################----################ ###################-------############## #################-----------############ ##############---------------######### ##########-------------------####### #######-----------------------#### ##---------------------------# ---------------------------- ---------------------- -------------- Global CMT Convention Moment Tensor: R T P 6.30e+20 -1.36e+21 3.81e+21 -1.36e+21 -2.10e+22 -3.15e+20 3.81e+21 -3.15e+20 2.04e+22 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20130827005143/index.html |
Contributor Code Type Magnitude Depth NP1 NP2 us nn00421303-neic-mwr Mwr 4.2 11.0 km 315°, 87°, 173° 45°, 83°, 3° us nn00421303-neic-mwr Type Mwr Moment 2.14e+15 N-m Magnitude 4.2 Percent DC 86% Depth 11.0 km Author neic Updated 2013-08-27 16:38:35 UTC Principal Axes Axis Value Plunge Azimuth T 2.064 7° 270° N 0.141 82° 112° P -2.205 3° 360° Nodal Planes Plane Strike Dip Rake NP1 315° 87° 173° NP2 45° 83° 3° |
(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 a -30 a 180 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.06 n 3The results of this grid search from 0.5 to 19 km depth are as follow:
DEPTH STK DIP RAKE MW FIT WVFGRD96 0.5 35 50 -25 3.80 0.3155 WVFGRD96 1.0 40 60 -20 3.80 0.3412 WVFGRD96 2.0 40 55 -20 3.93 0.4623 WVFGRD96 3.0 40 55 -20 3.98 0.5401 WVFGRD96 4.0 40 55 -20 4.01 0.5945 WVFGRD96 5.0 45 65 -10 4.02 0.6347 WVFGRD96 6.0 45 70 -5 4.04 0.6695 WVFGRD96 7.0 45 75 5 4.05 0.6979 WVFGRD96 8.0 45 70 -5 4.09 0.7230 WVFGRD96 9.0 45 70 -5 4.10 0.7418 WVFGRD96 10.0 45 75 5 4.11 0.7573 WVFGRD96 11.0 45 80 5 4.13 0.7662 WVFGRD96 12.0 45 80 5 4.14 0.7715 WVFGRD96 13.0 45 80 5 4.15 0.7732 WVFGRD96 14.0 45 80 10 4.16 0.7710 WVFGRD96 15.0 45 80 10 4.17 0.7651 WVFGRD96 16.0 45 80 10 4.17 0.7569 WVFGRD96 17.0 45 80 10 4.18 0.7472 WVFGRD96 18.0 45 80 10 4.19 0.7348 WVFGRD96 19.0 45 80 10 4.19 0.7223 WVFGRD96 20.0 45 80 10 4.20 0.7080 WVFGRD96 21.0 45 80 10 4.21 0.6937 WVFGRD96 22.0 45 80 10 4.21 0.6781 WVFGRD96 23.0 45 80 10 4.22 0.6626 WVFGRD96 24.0 45 80 10 4.22 0.6471 WVFGRD96 25.0 45 80 10 4.23 0.6311 WVFGRD96 26.0 45 80 15 4.23 0.6162 WVFGRD96 27.0 45 80 15 4.24 0.6012 WVFGRD96 28.0 45 80 15 4.24 0.5865 WVFGRD96 29.0 45 80 15 4.25 0.5721
The best solution is
WVFGRD96 13.0 45 80 5 4.15 0.7732
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 a -30 a 180 rtr taper w 0.1 hp c 0.02 n 3 lp c 0.06 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. |
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: