USGS Body-Wave Moment Tensor Solution
NEAR ISLANDS, ALEUTIAN ISLANDS
12/09/09 19:23:53.83 Epicenter: 52.822 174.904 MW 5.5 USGS MOMENT TENSOR SOLUTION Depth 110 No. of sta: 42 Moment Tensor; Scale 10**17 Nm Mrr=-0.43 Mtt=-0.65 Mpp= 1.08 Mrt=-1.78 Mrp=-0.67 Mtp= 0.31 Principal axes: T Val= 1.87 Plg=34 Azm=126 N 0.47 27 236 P -2.34 44 354 Best Double Couple:Mo=2.1*10**17 NP1:Strike= 58 Dip=85 Slip= -63 NP2: 158 27 -169
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.