USGS Centroid Moment Solution
OFF W COAST OF NORTHERN SUMATRA
12/01/10 18:36:59.49 Epicenter: 2.452 93.209 MW 7.2 USGS CENTROID MOMENT TENSOR 12/01/10 18:37:25.00 Centroid: 2.502 92.754 Depth 10 No. of sta: 156 Moment Tensor; Scale 10**19 Nm Mrr=-0.55 Mtt=-2.70 Mpp= 3.25 Mrt= 1.29 Mrp=-2.69 Mtp=-5.95 Principal axes: T Val= 7.95 Plg=19 Azm= 59 N -1.56 70 228 P -6.39 3 328 Best Double Couple:Mo=7.2*10**19 NP1:Strike=195 Dip=79 Slip= 16 NP2: 102 74 169
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.
