USGS WPhase Moment Solution
OFF EAST COAST OF HONSHU, JAPAN
12/12/07 8:31:14 Epicenter: 37.938 143.762 MW 6.2 USGS/WPHASE CENTROID MOMENT TENSOR 12/12/07 08:31:14.00 Centroid: 37.838 143.635 Depth 11 No. of sta: 9 Moment Tensor; Scale 10**18 Nm Mrr=-1.27 Mtt=-0.34 Mpp= 1.60 Mrt=-2.27 Mrp=-0.38 Mtp= 1.01 Principal axes: T Val= 2.60 Plg=23 Azm=127 N = 0.55 30 232 P = -3.14 49 6 Best Double Couple:Mo=2.9*10**18 NP1:Strike=174 Dip=35 Slip=-153 NP2: 62 75 -58
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.