USGS Body-Wave Moment Tensor Solution
SANTA CRUZ ISLANDS
13/02/11 20:09:54.55 Epicenter: -11.018 165.583 MW 5.7 USGS MOMENT TENSOR SOLUTION Depth 11 No. of sta: 43 Moment Tensor; Scale 10**17 Nm Mrr= 0.28 Mtt= 3.08 Mpp=-3.37 Mrt=-1.76 Mrp=-1.31 Mtp=-0.66 Principal axes: T Val= 3.93 Plg=26 Azm=180 N 0.06 56 45 P -3.99 21 281 Best Double Couple:Mo=4.0*10**17 NP1:Strike=322 Dip=56 Slip= 4 NP2: 230 87 146
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.