USGS Body-Wave Moment Tensor Solution
OFF W COAST OF NORTHERN SUMATRA
13/05/14 19:18:18.90 Epicenter: 0.775 92.437 MW 5.7 USGS MOMENT TENSOR SOLUTION Depth 20 No. of sta: 49 Moment Tensor; Scale 10**17 Nm Mrr=-0.19 Mtt=-1.78 Mpp= 1.97 Mrt=-0.40 Mrp= 0.06 Mtp=-3.49 Principal axes: T Val= 4.07 Plg= 3 Azm=239 N -0.18 84 113 P -3.90 5 329 Best Double Couple:Mo=4.0*10**17 NP1:Strike= 14 Dip=84 Slip= -1 NP2: 104 89 -174
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.