USGS Body-Wave Moment Tensor Solution
12/12/10 16:53:09.15 Epicenter: -6.540 129.815 MW 7.1 USGS MOMENT TENSOR SOLUTION Depth 156 No. of sta: 42 Moment Tensor; Scale 10**19 Nm Mrr= 1.13 Mtt=-4.19 Mpp= 3.06 Mrt= 2.65 Mrp= 3.47 Mtp=-0.34 Principal axes: T Val= 5.89 Plg=39 Azm=281 N -0.25 39 52 P -5.64 27 166 Best Double Couple:Mo=5.8*10**19 NP1:Strike= 46 Dip=83 Slip= 51 NP2: 307 40 168
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.