Solution details

This is a deviatoric moment tensor solution and would not properly represent an explosive earthquake source. The moment tensor is a simplified representation of the seismic source that assumes that the earthquake occurred on one point on the map. Slip on a planar fault results in a pure double couple source. The moment tensor allows for sources that are more complicated than that. Any non-double couple components should be regarded with suspicion as they can be caused by a flawed velocity model (and corresponding synthetic seismograms). Currently, we use simple 1D velocity models that work well to locate earthquakes, however, we have not yet adequately tested how well they reproduce long-period ground motions. The double couple fault plane solution tends to be fairly robust and often compares well with the P wave first motion focal mechanism.

Solution parameters for 09033007060p Number of stations 4 Period range of data 10-50s Data type full waveform velocity traces Preferred event depth 46 km Scalar Moment 5.89492 dyn-cm Moment Magnitude 3.8 Variance Reduction 40.19 % Percent Double Couple 97.0 % Percent CLVD 3.0 % Solution Quality POOR

Waveform Matches

Instrument-corrected and bandpassed (10-50s) velocity traces are shown in black. Synthetics are shown in red and also have been bandpassed (10-50s). The velocity model used was vel.P3: P Velocity (km/s) Top of Layer (km) 5.40 0.0 6.38 4.0 6.59 9.0 6.73 16.0 6.86 20.0 6.95 25.0 7.80 41.0 Shear wave velocities are calculated from the Pwave velocities using a Vp/Vs ratio of 1.78.