Panama Exploration: A GPS-Based Kinematic Model for the Western Caribbean

Kobayashi, Dice
[email protected]

Whether the Panama region behaves as a tectonic block, a segmented terrane, or a deformation zone is difficult to determine by direct geologic observation because of thick vegetation and sediment cover. Presented here, based on Global Positioning System (GPS) data, are improved block kinematics of the western Caribbean and a new interpretation of tectonic behavior of the Panama region, with implications for tectonic development and subsurface structures in the petroleum reserve of eastern Panama.

This study is the first to comprehensively analyze the kinematics of Central America, using a spatially and temporally reinforced Global Positioning System (GPS) network covering the region from Guatemala to Colombia. Kinematic block modeling simultaneously solves for the Euler vectors of the Central American fore arc and the Panama Region, and coupling on block bounding faults that best describe the observed velocity field. Seismic reflection profiles, seismic tomography, hypocentral locations, and structural and geologic data are used to propose and approximate block boundaries. Published Euler vectors constrain block motion in the inversion of the three-dimensional GPS velocity data and earthquake slip vectors. Various block models are constructed to investigate the motion of the Panama Region.

The best-fit model suggests that the Panama Region acts as a single tectonic block moving northeastward at rates of 8.4-9.4 mm a^-1 relative to the Caribbean plate. This motion may be a non-theoretical form of tectonic escape from Cocos Ridge collision, redirected by northwestward forcing by the North Andes and Choco blocks in northwestern South America. The model result demonstrates westward motion of these blocks relative to the Panama Region, indicating north-south trending compressional structural features in the spotlighted petroleum reserve.

AAPG Search and Discovery Article #90162©2013 Pacific Section AAPG, SPE and SEPM Joint Technical Conference, Monterey, California, April 19-25, 2013