USGS Body-Wave Moment Tensor Solution
NEAR EAST COAST OF HONSHU, JAPAN
13/01/08 07:51:31.09 Epicenter: 40.183 142.366 MW 5.4 USGS MOMENT TENSOR SOLUTION Depth 35 No. of sta: 63 Moment Tensor; Scale 10**17 Nm Mrr= 1.10 Mtt= 0.08 Mpp=-1.18 Mrt= 0.36 Mrp= 1.10 Mtp=-0.82 Principal axes: T Val= 1.55 Plg=68 Azm=273 N 0.46 7 22 P -2.01 20 115 Best Double Couple:Mo=1.8*10**17 NP1:Strike= 19 Dip=66 Slip= 82 NP2: 218 26 107
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.