USGS Body-Wave Moment Tensor Solution
12/04/11 22:55:13.64 Epicenter: 18.311 -102.699 MW 6.5 USGS MOMENT TENSOR SOLUTION Depth 20 No. of sta: 65 Moment Tensor; Scale 10**18 Nm Mrr= 2.28 Mtt=-2.30 Mpp= 0.02 Mrt= 5.06 Mrp=-2.01 Mtp= 0.85 Principal axes: T Val= 5.82 Plg=57 Azm= 24 N 0.29 2 291 P -6.10 33 200 Best Double Couple:Mo=6.0*10**18 NP1:Strike=284 Dip=12 Slip= 82 NP2: 111 78 92
The figure above shows a visual representation of the style of faulting (focal mechanism) derived from the estimated moment tensor. Shaded areas show quadrants of the focal sphere in which the P-wave first-motions are away from the source, and unshaded areas show quadrants in which the P-wave first-motions are toward the source. The dots represent the axis of maximum compressional strain (in black, called the "P-axis") and the axis of maximum extensional strain (in white, called the "T-axis") resulting from the earthquake.