RT Journal Article
T1 Active faults of El Salvador
A1 Martínez Díaz, José Jesús
A1 Álvarez Gómez, José Antonio
A1 Staller, Alejandra
A1 Alonso Henar, Jorge
A1 Canora Catalán, Carolina
A1 Insua Arévalo, Juan Miguel
A1 Tsige Beyene, Meaza
A1 Villamor Pérez, María Pilar
A1 Herrero Barbero, Paula
A1 Hernández Moreno, Catalina
A1 Hernández, Walter
A1 Hernández, Douglas
A1 Marroquín, Griselda
A1 Mixco, Luis
AB In this work we present a review of the current state of knowledge of the active faults in El Salvador and its seismo-tectonic implications. An updated map of active fault traces is combined with the spatial analysis of shallow seismicity, focal mechanisms, recent geodetic GPS velocities, local strain estimations and morpho-tectonic features to provide a synoptic view of the active tectonics of the El Salvador. The major faults selected as potential seismic sources bound tectonic blocks or regions that include GPS sites with consistent relative velocity vectors. We propose several active tectonic domains along El Salvador controlled by three current deformation regimes: a crustal block in the forearc sliver dominated by rigid westward translation with the faster and more homogeneous GPS velocities; three zones dominated by E-W distributed extensional coaxial deformation; and two bands with a deformation compatible with transtensional regime. In the Western sector of the ESFZ, GPS velocities and local structure suggest that E-W extension concentrates along the NNW-SSE oriented Santa Ana volcanic axis and it could connect to the north with the extensional region of the Ipala Graben. This is consistent with to the eastward shift of the North America-Cocos-Caribbean triple junction and “the closing of the zipper” proposed in recent models that progressively slows down the strike-slip movement along the northern limit of the forearc sliver. In the central sector large GPS velocity gradient parallel to the volcanic arc may be associated to complex and discontinuous structure of the ESFZ driving slowdown of the westward movement of local tectonic blocks. The southeaster sector of the ESFZ is an incipient large pull-apart structure affecting a pre-existing extensional N-S oriented fabric that induces two tectonic subdomains, the eastern one undergo E-W coaxial extension and the western one characterized by transtensional strain regime. We propose a new structural segmentation of the ESFZ considering that this fault zone includes all those structures that accommodate the relative velocity between the forearc sliver and the Chortís block. The 38 active faults with surface traces that are mapped for more than 5 km long proposed in this work, with maximum potential magnitude Mw ranging from 5.98 to 7.94, will contribute to improve regional and local seismic sources databases and seismic hazard assessment.
PB Elsevier
SN 0895-9811
YR 2021
FD 2021-01
LK https://hdl.handle.net/20.500.14352/7644
UL https://hdl.handle.net/20.500.14352/7644
LA eng
NO Ministerio de Ciencia e Innovación (MICINN)
NO New Zealand MBIE SSIF
DS Docta Complutense
RD 10 abr 2025