USGS WPhase Moment Solution

TONGA REGION

12/11/17  5:12:56.00

Epicenter: -18.310 -172.374
MW 5.9

USGS/WPHASE CENTROID MOMENT TENSOR
12/11/17  5:12:56.00
Centroid:  -18.310 -172.163
Depth  11         No. of sta: 21
Moment Tensor;   Scale 10**17 Nm
  Mrr=-5.34       Mtt=-1.43
  Mpp= 6.77       Mrt= 1.29
  Mrp= 7.21       Mtp= 2.67
 Principal axes:
  T  Val= 10.85  Plg=24  Azm=284
  N     = -2.15       5      192
  P     = -8.70      65       90

Best Double Couple:Mo=9.9*10**17
 NP1:Strike= 26 Dip=21 Slip= -75
 NP2:       190     69       -95

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.