The ANSS event ID is nm600223 and the event page is at https://earthquake.usgs.gov/earthquakes/eventpage/nm600223/executive.
1975/06/13 22:40:27 36.54 -89.68 2 3.74 Missouri
USGS/SLU Moment Tensor Solution ENS 1975/06/13 22:40:27:0 36.540 -89.680 2.0 3.7 Missouri Stations used: Filtering commands used: Best Fitting Double Couple Mo = 5.13e+21 dyne-cm Mw = 3.74 Z = 9 km Plane Strike Dip Rake NP1 185 73 -148 NP2 85 60 -20 Principal Axes: Axis Value Plunge Azimuth T 5.13e+21 8 313 N 0.00e+00 54 211 P -5.13e+21 34 49 Moment Tensor: (dyne-cm) Component Value Mxx 7.83e+20 Mxy -4.24e+21 Mxz -1.08e+21 Myy 7.36e+20 Myz -2.32e+21 Mzz -1.52e+21 ########------ ###########----------- ###########--------------- T ##########----------------- ## ##########------------------- ###############------------ ------ ################------------ P ------- ################------------- -------- ################------------------------ #################------------------------- #################------------------------# #################----------------------### -###############---------------------##### ---############-----------------######## --------#######------------############# --------------######################## --------------###################### -------------##################### -----------################### ----------################## --------############## -----######### Global CMT Convention Moment Tensor: R T P -1.52e+21 -1.08e+21 2.32e+21 -1.08e+21 7.83e+20 4.24e+21 2.32e+21 4.24e+21 7.36e+20 Details of the solution is found at http://www.eas.slu.edu/eqc/eqc_mt/MECH.NA/19750613224027/index.html |
STK = 85 DIP = 60 RAKE = -20 MW = 3.74 HS = 9
The NDK file is 19750613224027.ndk
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Older earthquake were studied using analog seismograms, which were digitized and analyzed. The original data are not longer available. However focal mechanism solutions based on the waveforms are given in published literature. At the same time, a given earthquake may have been analyzed independently, and the reference is given here.
For this earthquake the source reference is the following:
Herrmann, R. B. (1979). Surface wave focal mechanisms for eastern North American earthquakes with tectonic implications, J. Geophys. Res.84, 3543-3552.
The CUS model used for the waveform synthetic seismograms and for the surface wave eigenfunctions and dispersion is as follows (The format is in the model96 format of Computer Programs in Seismology).
MODEL.01 CUS Model with Q from simple gamma values 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 1.0000 5.0000 2.8900 2.5000 0.172E-02 0.387E-02 0.00 0.00 1.00 1.00 9.0000 6.1000 3.5200 2.7300 0.160E-02 0.363E-02 0.00 0.00 1.00 1.00 10.0000 6.4000 3.7000 2.8200 0.149E-02 0.336E-02 0.00 0.00 1.00 1.00 20.0000 6.7000 3.8700 2.9020 0.000E-04 0.000E-04 0.00 0.00 1.00 1.00 0.0000 8.1500 4.7000 3.3640 0.194E-02 0.431E-02 0.00 0.00 1.00 1.00