USGS Body-Wave Moment Tensor Solution
12/09/11 01:28:19.43 Epicenter: 45.290 151.215 MW 5.5 USGS MOMENT TENSOR SOLUTION Depth 16 No. of sta: 73 Moment Tensor; Scale 10**17 Nm Mrr= 0.88 Mtt=-0.45 Mpp=-0.43 Mrt= 0.76 Mrp= 1.33 Mtp=-0.78 Principal axes: T Val= 1.74 Plg=60 Azm=285 N 0.26 11 34 P -2.00 28 130 Best Double Couple:Mo=1.9*10**17 NP1:Strike= 31 Dip=74 Slip= 79 NP2: 246 20 124
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.