USGS Body-Wave Moment Tensor Solution
NORTHERN MID-ATLANTIC RIDGE
12/10/05 00:15:41.96 Epicenter: 17.505 -46.460 MW 5.4 USGS MOMENT TENSOR SOLUTION Depth 4 No. of sta: 20 Moment Tensor; Scale 10**17 Nm Mrr=-0.70 Mtt= 0.26 Mpp= 0.45 Mrt=-0.19 Mrp= 1.50 Mtp=-0.40 Principal axes: T Val= 1.62 Plg=32 Azm=249 N 0.12 12 346 P -1.73 55 94 Best Double Couple:Mo=1.7*10**17 NP1:Strike=169 Dip=78 Slip= -78 NP2: 302 17 -135
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.