USGS Centroid Moment Solution
COSTA RICA
12/09/08 20:29:31.22 Epicenter: 10.073 -85.342 MW 5.7 USGS CENTROID MOMENT TENSOR 12/09/08 20:29:13.20 Centroid: 7.920 -85.894 Depth 40 No. of sta: 5 Moment Tensor; Scale 10**17 Nm Mrr= 4.20 Mtt=-1.98 Mpp=-2.22 Mrt= 2.63 Mrp=-0.17 Mtp= 2.08 Principal axes: T Val= 5.21 Plg=68 Azm=347 N -0.57 17 127 P -4.64 13 221 Best Double Couple:Mo=4.9*10**17 NP1:Strike=117 Dip=60 Slip= 70 NP2: 333 35 121
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.
