USGS Body-Wave Moment Tensor Solution
NORTH ISLAND OF NEW ZEALAND
12/12/07 18:19:06.59 Epicenter: -38.298 176.090 MW 6.4 USGS MOMENT TENSOR SOLUTION Depth 168 No. of sta: 42 Moment Tensor; Scale 10**18 Nm Mrr= 1.51 Mtt=-0.19 Mpp=-1.33 Mrt= 3.54 Mrp= 0.36 Mtp=-1.87 Principal axes: T Val= 4.44 Plg=49 Azm= 14 N -0.39 27 248 P -4.06 28 142 Best Double Couple:Mo=4.3*10**18 NP1:Strike=185 Dip=30 Slip= 23 NP2: 74 79 118
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.