USGS WPhase Moment Solution
OFF W COAST OF NORTHERN SUMATRA
12/04/11 8:38:38
Epicenter: 2.348 93.072
MW 8.6
USGS/WPHASE CENTROID MOMENT TENSOR
12/04/11 08:38:38.00
Centroid: 2.148 92.972
Depth 30 No. of sta: 29
Moment Tensor; Scale 10**21 Nm
Mrr= 1.68 Mtt=-6.46
Mpp= 4.78 Mrt= 3.13
Mrp=-3.17 Mtp=-6.87
Principal axes:
T Val= 10.15 Plg=26 Azm= 62
N = -0.23 61 261
P = -9.92 7 156
Best Double Couple:Mo=1.0*10**22
NP1:Strike=203 Dip=65 Slip= 14
NP2: 107 77 155
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.
http://earthquake.usgs.gov/earthquakes/eqarchives/fm/neic_c000905e_wmt.php