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Neotectonic development of the El Salvador Fault Zone and implications for deformation in the Central America Volcanic Arc: Insights from 4-D analog modeling experiments

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Alonso-Henar, Jorge and Schreurs, Guido and Martínez Díaz, José J. and Álvarez Gómez, José Antonio and Villamor Pérez, María Pilar (2015) Neotectonic development of the El Salvador Fault Zone and implications for deformation in the Central America Volcanic Arc: Insights from 4-D analog modeling experiments. Tectonics, 34 (1). pp. 131-151. ISSN 0278-7407

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Official URL: http://onlinelibrary.wiley.com/doi/10.1002/2014TC003723/abstract



Abstract

The El Salvador Fault Zone (ESFZ) is an active, approximately 150 km long and 20 km wide,
segmented, dextral strike-slip fault zone within the Central American Volcanic Arc striking N100°E. Although
several studies have investigated the surface expression of the ESFZ, little is known about its structure at depth
and its kinematic evolution. Structural field data and mapping suggest a phase of extension, at some stage
during the evolution of the ESFZ. This phase would explain dip-slip movements on structures that are currently
associated with the active, dominantly strike slip and that do not fit with the current tectonic regime. Field
observations suggest trenchward migration of the arc. Such an extension and trenchward migration of
the volcanic arc could be related to slab rollback of the Cocos plate beneath the Chortis Block during the
Miocene/Pliocene. We carried out 4-D analog model experiments to test whether an early phase of extension
is required to form the present-day fault pattern in the ESFZ. Our experiments suggest that a two-phase
tectonic evolution best explains the ESFZ: an early pure extensional phase linked to a segmented volcanic arc
is necessary to form the main structures. This extensional phase is followed by a strike-slip dominated
regime, which results in intersegment areas with local transtension and segments with almost pure strike-slip
motion. The results of our experiments combined with field data along the Central American Volcanic Arc
indicate that the slab rollback intensity beneath the Chortis Block is greater in Nicaragua and decreases
westward to Guatemala.


Item Type:Article
Uncontrolled Keywords:Volcanic, Tectonic, El Salvador Fault Zone
Subjects:Sciences > Geology > Geodynamics
ID Code:28850
Deposited On:26 Feb 2015 12:55
Last Modified:23 May 2018 12:55

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