USGS Body-Wave Moment Tensor Solution
OFF THE COAST OF OREGON
12/04/11 22:41:49.16 Epicenter: 43.623 -127.514 MW 5.7 USGS MOMENT TENSOR SOLUTION Depth 12 No. of sta: 28 Moment Tensor; Scale 10**17 Nm Mrr= 0.68 Mtt=-3.56 Mpp= 2.88 Mrt= 0.42 Mrp=-1.42 Mtp=-2.99 Principal axes: T Val= 4.61 Plg=21 Azm= 69 N 0.13 69 244 P -4.74 1 338 Best Double Couple:Mo=4.7*10**17 NP1:Strike=205 Dip=77 Slip= 16 NP2: 112 75 166
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.