Density structure and geometry of the Costa Rican subduction zone from 3-D gravity modeling and local earthquake data
| Autor: | Oscar H. Lücke, Ivonne G. Arroyo |
|---|---|
| Jazyk: | angličtina |
| Rok vydání: | 2015 |
| Předmět: |
010504 meteorology & atmospheric sciences
Stratigraphy Gravity Soil Science Density Geometry 010502 geochemistry & geophysics 01 natural sciences lcsh:Stratigraphy Geochemistry and Petrology Oceanic crust Seismology Earth-Surface Processes 0105 earth and related environmental sciences lcsh:QE640-699 geography geography.geographical_feature_category Volcanic arc Subduction Tectonics lcsh:QE1-996.5 Paleontology Geology Fracture zone lcsh:Geology Geophysics 13. Climate action Slab window Slab Intraplate earthquake |
| Zdroj: | Solid Earth, Vol 6, Iss 4, Pp 1169-1183 (2015) Solid Earth, 6, 1169-1183, 2015 Kérwá Universidad de Costa Rica instacron:UCR Solid Earth, 6 (4). pp. 1169-1183. |
| ISSN: | 1869-9529 1869-9510 |
| Popis: | 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 in Costa Rica is presented based on 3-D 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. Contrary to commonly assumed, 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 maximum 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 (> 75 km) 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. German Academic Exchange Service//DAAD/Alemania Special Priority Program 1257 “Mass Transport and Mass Distribution in the Earth System” of the German Research Foundation//DFG/Alemania UCR::Vicerrectoría de Docencia::Ciencias Básicas::Facultad de Ciencias::Escuela Centroamericana de Geología |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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