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

Moment Tensor Solution
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.

Moment Tensor Solution

Details on the W-phase inversion algorithm.