2010/11/07 00:43:23 69.1860 146.2250 10.0 5.10 Alaska
USGS Felt map for this earthquake
USGS/SLU Moment Tensor Solution ENS 2010/11/07 00:43:23:0 69.19 146.23 10.0 5.1 Alaska Stations used: AK.BWN AK.CCB AK.COLD AK.HDA AK.MDM AK.MLY AK.WRH CN.DAWY CN.INK IU.COLA US.EGAK Filtering commands used: hp c 0.02 n 3 lp c 0.0625 n 3 Best Fitting Double Couple Mo = 3.85e+23 dynecm Mw = 4.99 Z = 20 km Plane Strike Dip Rake NP1 10 80 15 NP2 277 75 170 Principal Axes: Axis Value Plunge Azimuth T 3.85e+23 18 234 N 0.00e+00 72 43 P 3.85e+23 3 143 Moment Tensor: (dynecm) Component Value Mxx 1.26e+23 Mxy 3.50e+23 Mxz 4.73e+22 Myy 9.21e+22 Myz 1.03e+23 Mzz 3.40e+22 ### ####### ########## ########### ############# ############## ############### ################ ################# ###################################### ################################ ########################## ####################### ###################### ##################### ### ############## ## T ############# # ############# ##############  ############# P ######### #### Global CMT Convention Moment Tensor: R T P 3.40e+22 4.73e+22 1.03e+23 4.73e+22 1.26e+23 3.50e+23 1.03e+23 3.50e+23 9.21e+22 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20101107004323/index.html 
STK = 10 DIP = 80 RAKE = 15 MW = 4.99 HS = 20.0
The waveform inversion is preferred.
The following compares this source inversion to others
USGS/SLU Moment Tensor Solution ENS 2010/11/07 00:43:23:0 69.19 146.23 10.0 5.1 Alaska Stations used: AK.BWN AK.CCB AK.COLD AK.HDA AK.MDM AK.MLY AK.WRH CN.DAWY CN.INK IU.COLA US.EGAK Filtering commands used: hp c 0.02 n 3 lp c 0.0625 n 3 Best Fitting Double Couple Mo = 3.85e+23 dynecm Mw = 4.99 Z = 20 km Plane Strike Dip Rake NP1 10 80 15 NP2 277 75 170 Principal Axes: Axis Value Plunge Azimuth T 3.85e+23 18 234 N 0.00e+00 72 43 P 3.85e+23 3 143 Moment Tensor: (dynecm) Component Value Mxx 1.26e+23 Mxy 3.50e+23 Mxz 4.73e+22 Myy 9.21e+22 Myz 1.03e+23 Mzz 3.40e+22 ### ####### ########## ########### ############# ############## ############### ################ ################# ###################################### ################################ ########################## ####################### ###################### ##################### ### ############## ## T ############# # ############# ##############  ############# P ######### #### Global CMT Convention Moment Tensor: R T P 3.40e+22 4.73e+22 1.03e+23 4.73e+22 1.26e+23 3.50e+23 1.03e+23 3.50e+23 9.21e+22 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/20101107004323/index.html 
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.

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:
hp c 0.02 n 3 lp c 0.0625 n 3The results of this grid search from 0.5 to 19 km depth are as follow:
DEPTH STK DIP RAKE MW FIT WVFGRD96 0.5 195 60 30 4.65 0.3835 WVFGRD96 1.0 0 90 5 4.60 0.3991 WVFGRD96 2.0 180 90 5 4.67 0.4672 WVFGRD96 3.0 0 90 5 4.71 0.5092 WVFGRD96 4.0 180 90 5 4.74 0.5370 WVFGRD96 5.0 180 85 5 4.77 0.5580 WVFGRD96 6.0 185 80 10 4.79 0.5801 WVFGRD96 7.0 185 80 10 4.81 0.6029 WVFGRD96 8.0 10 70 15 4.83 0.6238 WVFGRD96 9.0 10 70 15 4.85 0.6431 WVFGRD96 10.0 10 70 15 4.86 0.6617 WVFGRD96 11.0 10 75 20 4.88 0.6789 WVFGRD96 12.0 10 75 20 4.90 0.6978 WVFGRD96 13.0 10 75 20 4.91 0.7132 WVFGRD96 14.0 10 75 15 4.92 0.7266 WVFGRD96 15.0 10 75 15 4.93 0.7380 WVFGRD96 16.0 10 75 15 4.94 0.7460 WVFGRD96 17.0 10 80 15 4.96 0.7530 WVFGRD96 18.0 10 80 15 4.97 0.7574 WVFGRD96 19.0 10 80 15 4.98 0.7600 WVFGRD96 20.0 10 80 15 4.99 0.7609 WVFGRD96 21.0 10 80 15 5.00 0.7590 WVFGRD96 22.0 10 80 15 5.00 0.7558 WVFGRD96 23.0 10 80 15 5.01 0.7505 WVFGRD96 24.0 10 80 15 5.02 0.7433 WVFGRD96 25.0 10 80 15 5.03 0.7347 WVFGRD96 26.0 10 80 15 5.03 0.7246 WVFGRD96 27.0 10 80 15 5.04 0.7135 WVFGRD96 28.0 10 80 15 5.05 0.7016 WVFGRD96 29.0 10 80 15 5.06 0.6889
The best solution is
WVFGRD96 20.0 10 80 15 4.99 0.7609
The mechanism correspond to the best fit is

The best fit as a function of depth is given in the following figure:

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 observedpredicted 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
hp c 0.02 n 3 lp c 0.0625 n 3

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.
Should the national backbone of the USGS Advanced National Seismic System (ANSS) be implemented with an interstation separation of 300 km, it is very likely that an earthquake such as this would have been recorded at distances on the order of 100200 km. This means that the closest station would have information on source depth and mechanism that was lacking here.
Dr. Harley Benz, USGS, provided the USGS USNSN digital data. The digital data used in this study were provided by Natural Resources Canada through their AUTODRM site http://www.seismo.nrcan.gc.ca/nwfa/autodrm/autodrm_req_e.php, and IRIS using their BUD interface.
Thanks also to the many seismic network operators whose dedication make this effort possible: University of Alaska, University of Washington, Oregon State University, University of Utah, Montana Bureas of Mines, UC Berkely, Caltech, UC San Diego, Saint L ouis University, Universityof Memphis, Lamont Doehrty Earth Observatory, Boston College, the Iris stations and the Transportable Array of EarthScope.
The CUS used for the waveform synthetic seismograms and for the surface wave eigenfunctions and dispersion is as follows:
MODEL.01 CUS Model with Q from simple gamma values ISOTROPIC KGS FLAT EARTH 1D CONSTANT VELOCITY LINE08 LINE09 LINE10 LINE11 H(KM) VP(KM/S) VS(KM/S) RHO(GM/CC) QP QS ETAP ETAS FREFP FREFS 1.0000 5.0000 2.8900 2.5000 0.172E02 0.387E02 0.00 0.00 1.00 1.00 9.0000 6.1000 3.5200 2.7300 0.160E02 0.363E02 0.00 0.00 1.00 1.00 10.0000 6.4000 3.7000 2.8200 0.149E02 0.336E02 0.00 0.00 1.00 1.00 20.0000 6.7000 3.8700 2.9020 0.000E04 0.000E04 0.00 0.00 1.00 1.00 0.0000 8.1500 4.7000 3.3640 0.194E02 0.431E02 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:
DATE=Sun Nov 7 05:55:19 CST 2010