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Density Structure and Geometry of the Costa Rican Subduction Zone from 3-d Gravity Modeling and Local Earthquake Data : Volume 7, Issue 3 (14/07/2015)

By Lücke, O. H.

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Book Id: WPLBN0004022059
Format Type: PDF Article :
File Size: Pages 37
Reproduction Date: 2015

Title: Density Structure and Geometry of the Costa Rican Subduction Zone from 3-d Gravity Modeling and Local Earthquake Data : Volume 7, Issue 3 (14/07/2015)  
Author: Lücke, O. H.
Volume: Vol. 7, Issue 3
Language: English
Subject: Science, Solid, Earth
Collections: Periodicals: Journal and Magazine Collection, Copernicus GmbH
Historic
Publication Date:
2015
Publisher: Copernicus Gmbh, Göttingen, Germany
Member Page: Copernicus Publications

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Arroyo, I. G., & Lücke, O. H. (2015). Density Structure and Geometry of the Costa Rican Subduction Zone from 3-d Gravity Modeling and Local Earthquake Data : Volume 7, Issue 3 (14/07/2015). Retrieved from http://worldlibrary.in/


Description
Description: University of Costa Rica, National Seismological Network, 214-2060 San Pedro, Costa Rica. The eastern part of the oceanic Cocos Plate presents a heterogeneous crustal structure due to diverse origins and ages as well as plate-hot spot interactions which originated the Cocos Ridge, a structure that converges with the Caribbean Plate in southeastern Costa Rica. The complex structure of the oceanic plate directly influences the dynamics and geometry of the subduction zone along the Middle American Trench. In this paper an integrated interpretation of the slab geometry is presented based on three-dimensional density modeling of combined satellite and surface gravity data, constrained by available geophysical and geological data and seismological information obtained from local networks. The results show the continuation of steep subduction geometry from the Nicaraguan margin into Northwestern Costa Rica, followed by a moderate dipping slab under the Central Cordillera toward the end of the Central American Volcanic Arc. To the southeast end of the volcanic arc, our preferred model shows a steep, coherent slab that extends up to the landward projection of the Panama Fracture Zone. Overall, a gradual change in the depth of the intraplate seismicity is observed, reaching 220 km in the northwestern part, and becoming progressively shallower toward the southeast, where it reaches a terminal depth of 75 km. The changes in the terminal depth of the observed seismicity correlate with the increased density in the modeled slab. The absence of intermediate depth intraplate seismicity in the southeastern section and the higher densities for the subducted slab in this area, support a model in which dehydration reactions in the subducted slab cease at a shallower depth, originating an anhydrous and thus aseismic slab.

Summary
Density structure and geometry of the Costa Rican subduction zone from 3-D gravity modeling and local earthquake data

Excerpt
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