Three Dimensional Visualization of Earthquake Epicenters and Focal Mechanism Solutions

William J. Sercombe, John L. Futch, and Karen Hoffman

Three dimensional visualization provides enhanced interpretive capabilities for modeling patterns of earthquake epicenters and focal mechanism solutions. Modeling of modern earthquakes is important for geohazard studies and for understanding structural genesis through uniformitarianism. Two dimensional plotting of earthquake epicenters and focal mechanism solutions has revealed the complex nature of deformed belts, subduction complexes and other seismically active areas. These data have revealed the heterogeneous mixture of thrust, strike-slip and normal faulting in spatially complex patterns not typically represented in geologic models. The Vrancea window of Romania, as an example, has dangerously destructive earthquake activity. 3D analysis shows a compact round cluster ng pipe of deep epicenters with vertical tensile axes indicating the pattern is imploding. 3D additionally reveals the upward spiraling heliform character to the earthquakes indicating possible incipient igneous activity directly on trend with volcanics to the northwest. This may assist insight into magma movement mechanisms. 3D visualization of earthquakes has better delineated the continent to continent subduction complex of the Hindu Kush. The 3D perspective on the partitioning of the "typical Andean Subduction" in South America, the Antilles arc on the Caribbean plate boundary, the Aleutian arc, the Calabrian and Hellenic arcs and the complex Japanese arc, reveals heterogeneity that is in contrast to the typical two dimensional Beniof zone or subduction process depicted in the geolog c literature.

AAPG Search and Discover Article #91019©1996 AAPG Convention and Exhibition 19-22 May 1996, San Diego, California