RT Journal Article
T1 Neotectonic development of the El Salvador FaultZone and implications for deformation in theCentral America Volcanic Arc: Insights from4-D analog modeling experiments
A1 Alonso Henar, Jorge
A1 Schreurs, Guido
A1 Martínez Díaz, José J.
A1 Álvarez Gómez, José Antonio
A1 Villamor Pérez, María Pilar
AB 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.
PB Amercian Geophysical Union
SN 0278-7407
YR 2015
FD 2015
LK https://hdl.handle.net/20.500.14352/33818
UL https://hdl.handle.net/20.500.14352/33818
LA eng
DS Docta Complutense
RD 16 may 2024