USGS Body-Wave Moment Tensor Solution
HOKKAIDO, JAPAN REGION
13/02/02 14:17:34.84 Epicenter: 42.828 143.093 MW 6.9 USGS MOMENT TENSOR SOLUTION Depth 107 No. of sta:122 Moment Tensor; Scale 10**19 Nm Mrr= 0.02 Mtt= 0.11 Mpp=-0.13 Mrt= 2.75 Mrp=-0.13 Mtp=-0.03 Principal axes: T Val= 2.82 Plg=45 Azm= 3 N -0.13 0 273 P -2.68 45 182 Best Double Couple:Mo=2.8*10**19 NP1:Strike=136 Dip= 1 Slip= -47 NP2: 273 90 -90
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.