USGS Body-Wave Moment Tensor Solution
NORTHERN SUMATRA, INDONESIA
13/01/10 13:47:03.75 Epicenter: 4.788 95.122 MW 5.7 USGS MOMENT TENSOR SOLUTION Depth 40 No. of sta: 56 Moment Tensor; Scale 10**17 Nm Mrr= 3.88 Mtt=-1.37 Mpp=-2.50 Mrt= 2.31 Mrp=-1.37 Mtp= 1.59 Principal axes: T Val= 4.82 Plg=70 Azm= 18 N -0.45 10 137 P -4.38 17 230 Best Double Couple:Mo=4.6*10**17 NP1:Strike=335 Dip=29 Slip= 111 NP2: 132 63 79
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.