USGS WPhase Moment Solution

SOUTHEASTERN ALASKA

13/01/05  8:58:19

Epicenter:  55.291 -134.727
MW 7.5

USGS/WPHASE CENTROID MOMENT TENSOR
13/01/05 08:58:19.00
Centroid:   55.891 -134.906
Depth  11         No. of sta:106
Moment Tensor;   Scale 10**20 Nm
  Mrr= 0.04       Mtt=-1.56
  Mpp= 1.52       Mrt= 0.93
  Mrp= 0.41       Mtp= 1.26
 Principal axes:
  T  Val=  2.21  Plg=19  Azm=293
  N     =  0.05      62       65
  P     = -2.25      18      196

Best Double Couple:Mo=2.2*10**20
 NP1:Strike=335 Dip=63 Slip= 180
 NP2:        65     90        27

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.