USGS Centroid Moment Solution

OFF W COAST OF NORTHERN SUMATRA

12/04/11 10:43:10.76

Epicenter:   0.829   92.434
MW 8.2

USGS CENTROID MOMENT TENSOR
12/04/11 10:43:50.29
Centroid:   0.921   92.488
Depth  43         No. of sta: 36
Moment Tensor;   Scale 10**21 Nm
  Mrr= 0.45       Mtt=-1.30
  Mpp= 0.85       Mrt= 0.21
  Mrp=-0.84       Mtp=-1.63
 Principal axes:
  T  Val=  2.15  Plg=26  Azm= 63
  N        0.05      63      231
  P       -2.20       5      331

Best Double Couple:Mo=2.2*10**21
 NP1:Strike=200 Dip=75 Slip=  23
 NP2:       104     68       164

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