2014/10/02 18:01:24 37.242 -97.903 5.0 4.4 Kansas
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution ENS 2014/10/02 18:01:24:0 37.24 -97.90 5.0 4.4 Kansas Stations used: AG.HHAR AG.WHAR GS.KAN13 GS.OK025 GS.OK026 GS.OK027 GS.OK028 GS.OK029 N4.L34B N4.N33B N4.N35B N4.R32B N4.T35B N4.U38B N4.Z35B N4.Z38B NM.UALR OK.BCOK OK.CROK OK.FNO OK.QUOK OK.U32A OK.X37A TA.ABTX TA.BGNE TA.KSCO TA.TUL1 TA.U40A TA.W39A TA.W41B TA.WHTX TA.X40A US.AMTX US.CBKS US.KSU1 US.MIAR US.WMOK Filtering commands used: cut o DIST/3.3 -30 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.06 n 3 Best Fitting Double Couple Mo = 3.67e+22 dyne-cm Mw = 4.31 Z = 3 km Plane Strike Dip Rake NP1 72 45 -85 NP2 245 45 -95 Principal Axes: Axis Value Plunge Azimuth T 3.67e+22 0 159 N 0.00e+00 4 249 P -3.67e+22 86 67 Moment Tensor: (dyne-cm) Component Value Mxx 3.18e+22 Mxy -1.26e+22 Mxz -9.57e+20 Myy 4.80e+21 Myz -2.05e+21 Mzz -3.66e+22 ############## ###################### ############################ ############################## #################------------##### #############----------------------# ###########--------------------------- #########------------------------------- #######--------------------------------# #######--------------- ---------------## #####----------------- P --------------### ####------------------ -------------#### ###---------------------------------###### ##--------------------------------###### #-------------------------------######## ##--------------------------########## ####-------------------############# ################################## ############################## ############################ ################ ### ############ T Global CMT Convention Moment Tensor: R T P -3.66e+22 -9.57e+20 2.05e+21 -9.57e+20 3.18e+22 1.26e+22 2.05e+21 1.26e+22 4.80e+21 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20141002180124/index.html |
STK = 245 DIP = 45 RAKE = -95 MW = 4.31 HS = 3.0
The NDK file is 20141002180124.ndk The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution ENS 2014/10/02 18:01:24:0 37.24 -97.90 5.0 4.4 Kansas Stations used: AG.HHAR AG.WHAR GS.KAN13 GS.OK025 GS.OK026 GS.OK027 GS.OK028 GS.OK029 N4.L34B N4.N33B N4.N35B N4.R32B N4.T35B N4.U38B N4.Z35B N4.Z38B NM.UALR OK.BCOK OK.CROK OK.FNO OK.QUOK OK.U32A OK.X37A TA.ABTX TA.BGNE TA.KSCO TA.TUL1 TA.U40A TA.W39A TA.W41B TA.WHTX TA.X40A US.AMTX US.CBKS US.KSU1 US.MIAR US.WMOK Filtering commands used: cut o DIST/3.3 -30 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 n 3 lp c 0.06 n 3 Best Fitting Double Couple Mo = 3.67e+22 dyne-cm Mw = 4.31 Z = 3 km Plane Strike Dip Rake NP1 72 45 -85 NP2 245 45 -95 Principal Axes: Axis Value Plunge Azimuth T 3.67e+22 0 159 N 0.00e+00 4 249 P -3.67e+22 86 67 Moment Tensor: (dyne-cm) Component Value Mxx 3.18e+22 Mxy -1.26e+22 Mxz -9.57e+20 Myy 4.80e+21 Myz -2.05e+21 Mzz -3.66e+22 ############## ###################### ############################ ############################## #################------------##### #############----------------------# ###########--------------------------- #########------------------------------- #######--------------------------------# #######--------------- ---------------## #####----------------- P --------------### ####------------------ -------------#### ###---------------------------------###### ##--------------------------------###### #-------------------------------######## ##--------------------------########## ####-------------------############# ################################## ############################## ############################ ################ ### ############ T Global CMT Convention Moment Tensor: R T P -3.66e+22 -9.57e+20 2.05e+21 -9.57e+20 3.18e+22 1.26e+22 2.05e+21 1.26e+22 4.80e+21 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20141002180124/index.html |
Moment 3.44e+15 N-m Magnitude 4.3 Percent DC 89% Depth 2.0 km Updated 2014-10-02 18:31:10 UTC Author us Catalog us Contributor us Code us_b000si7g_mwr Principal Axes Axis Value Plunge Azimuth T 3.527 2 165 N -0.186 7 255 P -3.341 83 55 Nodal Planes Plane Strike Dip Rake NP1 81 48 -81 NP2 248 43 -100 |
(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 -30 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 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 1.0 250 45 -90 4.15 0.4076 WVFGRD96 2.0 75 45 -80 4.24 0.4784 WVFGRD96 3.0 245 45 -95 4.31 0.4952 WVFGRD96 4.0 85 50 -65 4.33 0.4277 WVFGRD96 5.0 100 65 -45 4.30 0.3575 WVFGRD96 6.0 110 85 -30 4.28 0.3369 WVFGRD96 7.0 295 70 15 4.29 0.3464 WVFGRD96 8.0 290 90 -40 4.34 0.3424 WVFGRD96 9.0 115 75 40 4.35 0.3583 WVFGRD96 10.0 115 75 40 4.36 0.3728 WVFGRD96 11.0 115 75 40 4.37 0.3856 WVFGRD96 12.0 115 70 35 4.39 0.3964 WVFGRD96 13.0 115 70 35 4.40 0.4056 WVFGRD96 14.0 120 70 40 4.41 0.4127 WVFGRD96 15.0 120 70 40 4.42 0.4182 WVFGRD96 16.0 120 70 40 4.42 0.4219 WVFGRD96 17.0 120 70 40 4.43 0.4241 WVFGRD96 18.0 120 70 40 4.44 0.4250 WVFGRD96 19.0 120 70 40 4.45 0.4248 WVFGRD96 20.0 120 70 40 4.45 0.4236 WVFGRD96 21.0 120 70 40 4.47 0.4198 WVFGRD96 22.0 120 70 40 4.47 0.4168 WVFGRD96 23.0 120 70 40 4.48 0.4132 WVFGRD96 24.0 120 70 40 4.49 0.4093 WVFGRD96 25.0 120 70 40 4.49 0.4049 WVFGRD96 26.0 120 70 40 4.50 0.3999 WVFGRD96 27.0 115 75 40 4.50 0.3948 WVFGRD96 28.0 115 75 40 4.51 0.3894 WVFGRD96 29.0 210 50 35 4.49 0.3882
The best solution is
WVFGRD96 3.0 245 45 -95 4.31 0.4952
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 -30 o DIST/3.3 +50 rtr taper w 0.1 hp c 0.03 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. |
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: