USGS Body-Wave Moment Tensor Solution
BAJA CALIFORNIA, MEXICO
12/04/12 07:15:53.60 Epicenter: 28.884 -113.117 MW 6.9 USGS MOMENT TENSOR SOLUTION Depth 20 No. of sta: 36 Moment Tensor; Scale 10**19 Nm Mrr=-0.26 Mtt=-1.72 Mpp= 1.98 Mrt= 0.50 Mrp= 0.51 Mtp= 1.39 Principal axes: T Val= 2.59 Plg=13 Azm=289 N -0.35 74 72 P -2.24 9 197 Best Double Couple:Mo=2.4*10**19 NP1:Strike=333 Dip=74 Slip= 177 NP2: 64 88 16
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.