USGS WPhase Moment Solution
TONGA
13/ 2/15 3: 2:23.00 Epicenter: -19.718 -174.475 MW 5.7 USGS/WPHASE CENTROID MOMENT TENSOR 13/ 2/15 3: 2:23.00 Centroid: -19.918 -174.263 Depth 80 No. of sta: 15 Moment Tensor; Scale 10**17 Nm Mrr=-2.76 Mtt= 0.24 Mpp= 2.52 Mrt=-0.13 Mrp= 4.16 Mtp= 0.73 Principal axes: T Val= 4.88 Plg=28 Azm=278 N = 0.20 7 183 P = -5.09 60 79 Best Double Couple:Mo=5.0*10**17 NP1:Strike= 29 Dip=18 Slip= -63 NP2: 181 74 -98
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.
