USGS Centroid Moment Solution

OFF W COAST OF NORTHERN SUMATRA

12/04/11 08:38:35.72

Epicenter:   2.350   93.039
MW 8.6

USGS CENTROID MOMENT TENSOR
12/04/11 08:39:32.59
Centroid:   2.244   93.100
Depth  40         No. of sta: 61
Moment Tensor;   Scale 10**21 Nm
  Mrr= 0.40       Mtt=-5.39
  Mpp= 4.98       Mrt= 1.74
  Mrp=-1.57       Mtp=-6.31
 Principal axes:
  T  Val=  8.55  Plg=15  Azm= 64
  N       -0.08      74      267
  P       -8.47       6      155

Best Double Couple:Mo=8.5*10**21
 NP1:Strike=201 Dip=75 Slip=   6
 NP2:       109     84       165

Moment Tensor Solution
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.

Moment Tensor Solution