USGS WPhase Moment Solution
SANTA CRUZ ISLANDS
12/01/09 4:07:16 Epicenter: -10.556 165.159 MW 6.4 USGS/WPHASE CENTROID MOMENT TENSOR 12/01/09 04:07:16.00 Centroid: -10.356 165.159 Depth 40 No. of sta: 21 Moment Tensor; Scale 10**18 Nm Mrr= 1.44 Mtt=-2.96 Mpp= 1.52 Mrt= 1.33 Mrp=-2.11 Mtp=-2.49 Principal axes: T Val= 4.58 Plg=38 Azm= 64 N = -0.48 51 253 P = -4.09 4 157 Best Double Couple:Mo=4.4*10**18 NP1:Strike=208 Dip=60 Slip= 26 NP2: 104 67 148
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.
