USGS/SLU Regional Moment Solution
12/11/12 23:18:42.63 Epicenter: 42.587 19.018 MW 4.4 USGS/SLU REGIONAL MOMENT TENSOR Depth 25 No. of sta: 19 Moment Tensor; Scale 10**15 Nm Mrr= 5.70 Mtt=-4.76 Mpp=-0.93 Mrt= 0.63 Mrp=-1.20 Mtp= 2.13 Principal axes: T Val= 5.91 Plg=80 Azm= 81 N -0.10 8 296 P -5.81 5 205 Best Double Couple:Mo=5.9*10**15 NP1:Strike=286 Dip=40 Slip= 78 NP2: 122 51 100
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.