USGS Body-Wave Moment Tensor Solution
12/12/11 06:18:27.65 Epicenter: 0.574 126.262 MW 5.9 USGS MOMENT TENSOR SOLUTION Depth 48 No. of sta: 44 Moment Tensor; Scale 10**17 Nm Mrr= 6.06 Mtt=-0.49 Mpp=-5.57 Mrt= 1.27 Mrp=-3.91 Mtp=-4.89 Principal axes: T Val= 8.19 Plg=60 Azm= 48 N 0.86 27 203 P -9.05 11 298 Best Double Couple:Mo=8.7*10**17 NP1:Strike= 58 Dip=42 Slip= 133 NP2: 186 61 58
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.