USGS Body-Wave Moment Tensor Solution
OFF W COAST OF NORTHERN SUMATRA
12/01/10 18:36:59.49 Epicenter: 2.452 93.209 MW 7.1 USGS MOMENT TENSOR SOLUTION Depth 25 No. of sta: 67 Moment Tensor; Scale 10**19 Nm Mrr=-0.12 Mtt=-1.93 Mpp= 2.05 Mrt= 0.17 Mrp= 0.53 Mtp=-5.39 Principal axes: T Val= 5.82 Plg= 3 Azm=235 N -0.11 84 1 P -5.72 5 145 Best Double Couple:Mo=5.8*10**19 NP1:Strike=190 Dip=89 Slip= -6 NP2: 280 84 -179
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.