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
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.
