USGS Body-Wave Moment Tensor Solution
NORTHERN SUMATRA, INDONESIA
13/01/21 22:22:53.80 Epicenter: 4.949 96.082 MW 6.0 USGS MOMENT TENSOR SOLUTION Depth 8 No. of sta: 38 Moment Tensor; Scale 10**18 Nm Mrr= 0.09 Mtt=-1.20 Mpp= 1.11 Mrt= 0.03 Mrp= 0.39 Mtp=-0.21 Principal axes: T Val= 1.26 Plg=18 Azm=265 N -0.03 72 76 P -1.22 3 174 Best Double Couple:Mo=1.2*10**18 NP1:Strike=308 Dip=75 Slip= 169 NP2: 41 79 15
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.