USGS WPhase Moment Solution

OFF EAST COAST OF HONSHU, JAPAN

12/10/01 22:21:45

Epicenter:  39.852  143.046
MW 6.1

USGS/WPHASE CENTROID MOMENT TENSOR
12/10/01 22:21:45.00
Centroid:   39.852  143.046
Depth  19         No. of sta: 32
Moment Tensor;   Scale 10**18 Nm
  Mrr= 0.54       Mtt=-0.11
  Mpp=-0.43       Mrt= 0.52
  Mrp= 1.43       Mtp=-0.08
 Principal axes:
  T  Val=  1.65  Plg=53  Azm=291
  N     = -0.10       1      199
  P     = -1.55      36      108

Best Double Couple:Mo=1.6*10**18
 NP1:Strike=191 Dip= 9 Slip=  81
 NP2:        20     81        91

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.