USGS WPhase Moment Solution

TONGA

13/ 2/ 7  7:19:59.00

Epicenter: -15.586 -173.142
MW 5.8

USGS/WPHASE CENTROID MOMENT TENSOR
13/ 2/ 7  7:19:59.00
Centroid:  -15.486 -172.726
Depth  11         No. of sta: 42
Moment Tensor;   Scale 10**17 Nm
  Mrr= 5.05       Mtt=-1.08
  Mpp=-3.97       Mrt= 1.06
  Mrp= 5.54       Mtp=-0.65
 Principal axes:
  T  Val=  7.73  Plg=64  Azm=280
  N     = -0.94       0       11
  P     = -6.79      25      101

Best Double Couple:Mo=7.3*10**17
 NP1:Strike=192 Dip=19 Slip=  91
 NP2:        11     70        90

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.