USGS Body-Wave Moment Tensor Solution
MARIANA ISLANDS REGION
12/09/08 06:54:19.21 Epicenter: 21.517 145.921 MW 5.7 USGS MOMENT TENSOR SOLUTION Depth 5 No. of sta: 65 Moment Tensor; Scale 10**17 Nm Mrr= 0.26 Mtt= 0.27 Mpp=-0.53 Mrt=-1.99 Mrp= 3.71 Mtp=-0.18 Principal axes: T Val= 4.27 Plg=46 Azm=236 N -0.05 6 332 P -4.21 43 68 Best Double Couple:Mo=4.2*10**17 NP1:Strike=332 Dip=88 Slip= 84 NP2: 227 6 165
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.