USGS WPhase Moment Solution

SANTA CRUZ ISLANDS

12/01/09  4:07:16

Epicenter: -10.556  165.159
MW 6.4

USGS/WPHASE CENTROID MOMENT TENSOR
12/01/09 04:07:16.00
Centroid:  -10.356  165.159
Depth  40         No. of sta: 21
Moment Tensor;   Scale 10**18 Nm
  Mrr= 1.44       Mtt=-2.96
  Mpp= 1.52       Mrt= 1.33
  Mrp=-2.11       Mtp=-2.49
 Principal axes:
  T  Val=  4.58  Plg=38  Azm= 64
  N     = -0.48      51      253
  P     = -4.09       4      157

Best Double Couple:Mo=4.4*10**18
 NP1:Strike=208 Dip=60 Slip=  26
 NP2:       104     67       148

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.