USGS Body-Wave Moment Tensor Solution
11/02/11 20:05:31.66 OFFSHORE BIO-BIO, CHILE Epicenter: -36.397 -72.950 MW 6.8 USGS MOMENT TENSOR SOLUTION Depth 26 No. of sta: 49 Moment Tensor; Scale 10**19 Nm Mrr= 0.55 Mtt= 0.06 Mpp=-0.61 Mrt= 0.33 Mrp=-1.55 Mtp=-0.10 Principal axes: T Val= 1.69 Plg=54 Azm= 70 N 0.00 7 171 P -1.69 35 266 Best Double Couple:Mo=1.7*10**19 NP1:Strike= 28 Dip=12 Slip= 128 NP2: 169 80 82
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 form 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.