USGS WPhase Moment Solution
TONGA
13/ 2/19 22:29:0.00 Epicenter: -17.415 -173.424 MW 5.7 USGS/WPHASE CENTROID MOMENT TENSOR 13/ 2/19 22:29: 0.00 Centroid: -17.315 -173.738 Depth 45 No. of sta: 20 Moment Tensor; Scale 10**17 Nm Mrr= 2.46 Mtt=-1.98 Mpp=-0.49 Mrt=-0.81 Mrp= 2.80 Mtp= 1.30 Principal axes: T Val= 4.15 Plg=58 Azm=269 N = -0.54 20 141 P = -3.61 22 42 Best Double Couple:Mo=3.9*10**17 NP1:Strike= 99 Dip=29 Slip= 44 NP2: 329 70 112
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.
