USGS Body-Wave Moment Tensor Solution
11/12/11 01:47:25.81 Epicenter: 18.014 -99.801 MW 6.4 USGS MOMENT TENSOR SOLUTION Depth 60 No. of sta: 65 Moment Tensor; Scale 10**18 Nm Mrr=-4.44 Mtt= 3.60 Mpp= 0.85 Mrt=-2.25 Mrp= 0.41 Mtp=-1.74 Principal axes: T Val= 4.96 Plg=13 Azm=204 N 0.07 6 113 P -5.03 75 358 Best Double Couple:Mo=5.0*10**18 NP1:Strike=109 Dip=59 Slip= -97 NP2: 303 32 -78
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.