USGS Body-Wave Moment Tensor Solution
12/10/08 11:43:35.69 Epicenter: -4.457 129.115 MW 6.1 USGS MOMENT TENSOR SOLUTION Depth 10 No. of sta: 23 Moment Tensor; Scale 10**18 Nm Mrr= 1.52 Mtt=-0.86 Mpp=-0.66 Mrt=-0.76 Mrp=-0.24 Mtp= 0.82 Principal axes: T Val= 1.83 Plg=68 Azm=149 N -0.19 20 305 P -1.64 8 38 Best Double Couple:Mo=1.7*10**18 NP1:Strike=291 Dip=56 Slip= 65 NP2: 151 41 122
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.