USGS WPhase Moment Solution
OFF W. COAST OF N. ISLAND, N.Z.
12/07/03 10:36:16 Epicenter: -39.963 173.704 MW 6.3 USGS/WPHASE CENTROID MOMENT TENSOR 12/07/03 10:36:16.00 Centroid: -40.063 173.704 Depth 230 No. of sta: 21 Moment Tensor; Scale 10**18 Nm Mrr= 0.29 Mtt= 1.13 Mpp=-1.42 Mrt= 2.85 Mrp=-2.12 Mtp= 0.28 Principal axes: T Val= 3.88 Plg=43 Azm= 19 N = -0.18 20 129 P = -3.69 39 237 Best Double Couple:Mo=3.8*10**18 NP1:Strike= 34 Dip=20 Slip= 175 NP2: 129 88 70
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.
