Active faults of El Salvador

Martínez‐Díaz, J. J.; Álvarez‐Gómez, José A.; Staller, Alejandra; Alonso‐Henar, Jorge; Canora, Carolina; Insúa-Arévalo, Juan M.; Tsigé, Meaza; Villamor, Pilar; Herrero‐Barbero, Paula; Hernandez‐Moreno, Catalina; Hernández, Walter; Hernández, Daniela; Marroquín, Griselda; Mixco, Luis

doi:10.1016/j.jsames.2020.103038

Cited by 6 publications

(7 citation statements)

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“…Since the Nahualá outcrop is near the CAFA boundary, a similar area of oblique divergence could have occurred in the past along the volcanic arc west of the Guatemala City graben. The distributed zones of deformation in El Salvador occur between adjacent strike‐slip faults (e.g., Garibaldi et al., 2016; Martínez‐Díaz et al., 2021). Since the distributed deformation of this area is similar to the zones within the El Salvador fault zone, it suggests that a dextral fault—an extension of the active Jalpatagua fault—once continued further westward along the south side of the western Guatemala wedge within the active volcanic arc.…”

Section: Discussionmentioning

confidence: 99%

Deformation in Western Guatemala Associated With the NAFCA (North America‐Central American Forearc‐Caribbean) Triple Junction: Neotectonic Strain Localization Into the Guatemala City Graben

et al. 2022

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Recent structural and geodetic data define the Guatemala City graben region as the continental triple junction between the North American plate, Caribbean plate, and the Central American Forearc sliver. We present minor fault analysis, geochronological and geochemical analyses, and newly updated GPS velocities in western Guatemala, west of the Guatemala City graben, to characterize the magnitude and timing of extensional deformation in this poorly understood area. Elongations estimated from fault data are parallel (∼east‐west) and perpendicular to the Polochic‐Motagua fault system to the north, similar to geodetically measured active deformation observed east of the Guatemala City graben. Four new 40Ar/39Ar dates and correlation of tephra deposits suggest that faulting was active during the Pliocene, but ceased eastward toward the Guatemala City graben over time. From west to east, fault cessation occurred before the deposition of the Los Chocoyos ash (75 ka) and E tephra (51 ka). Faulting just west of the Guatemala City graben appears to be active, where a major fault cuts the most recent Amatitlán tephras. Based on this data, we propose a time‐progressive strain model for deformation related to North America‐Caribbean plate interactions, whereby distributed elongation of the westernmost Caribbean plate occurred during the Pliocene but localized mostly within the Guatemala City graben and nearby faults during the Pleistocene. Our model supports that: (a) The Guatemala City graben is effectively the western limit of the Caribbean plate; and (b) Western Guatemala, which was the trailing edge of the Caribbean plate, has been transferred to the forearc region.

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Section: Discussionmentioning

confidence: 99%

Deformation in Western Guatemala Associated With the NAFCA (North America‐Central American Forearc‐Caribbean) Triple Junction: Neotectonic Strain Localization Into the Guatemala City Graben

et al. 2022

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“…El Salvador country is located in the Central American Volcanic Arc (CAVA), which extends from Guatemala to Costa Rica along the active Pacific margin and ends to the north in a diffuse triple junction among the Cocos, Caribbean, and North American plates (Figure 1) [33][34][35][36].…”

Section: Geographical Tectonic and Geological Setting Of The El Salva...mentioning

confidence: 99%

2D FEM Numerical Prediction of Local Seismic Effects at San Salvador Municipality (El Salvador) Induced by 2001 Earthquakes

Faraone

Caravaggio

Chávez³

et al. 2023

Geosciences

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San Salvador Metropolitan Area (MASS) is an urbanized territory in the country of El Salvador, located between the San Salvador volcano and the Ilopango caldera, in a sub-flat area called “Valle de las Hamacas” (Valley of the Hammocks). The high seismicity of this area is due to the subduction zone of the Cocos plate that causes strong seismic events such as the earthquakes that occurred on 13 January (7.6 Mw) and 13 February 2001 (6.6 Mw). As part of the international cooperation project between Italy (AICS) and El Salvador University, the CASTES project focussed on natural hazards in the territory of El Salvador was launched. Therefore, 2D simulations are carried out along two sections to evaluate the Local Seismic Response (LSR) in the Southeast part of MASS territory. Results show spatially variable amplifications (from 3 to 6.5) in the period ranging 0.1–0.7 s and evidence of lateral FA variations that can be calculated only through 2D numerical analyses. Two amplified periods are recognised, 0.1–0.5 s and 0.4–0.8 s, due to the presence of two types of subsoil volcanic deposits: the shallow and soft Tierra Blanca deposits and the deeper and stiffer Volcanic ash and Tuff.

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“…The ESFZ was the source of the 13 February 2001 destructive earthquake (Mw 6.6), and it has great seismic potential, being able to generate earthquake magnitudes up to Mw 7.0, which makes this area especially interesting from a hazard point of view and has led to several studies [15,28,48,50,51]. A detailed review of each fault and its associated seismicity can be found in [52] and references therein.…”

Section: Figurementioning

confidence: 99%

“…We have compiled all the available earthquake focal mechanisms in El Salvador (see [52]). It is important to highlight that there are only a few obtained from earthquake magnitudes Mw < 3.0, which reduces data reliability and may lead to some errors.…”

Section: Incremental Strain Ellipsoid From Earthquake Focal Mechanismsmentioning

confidence: 99%

Active Triclinic Transtension in a Volcanic Arc: A Case of the El Salvador Fault Zone in Central America

et al. 2022

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The El Salvador Fault Zone (ESFZ) is part of the Central American Volcanic Arc and accommodates the oblique separation movement between the forearc sliver and the Chortis block (Caribbean Plate). In this work, a triclinic transtension model was applied to geological (fault-slip inversion, shape of volcanic calderas), seismic (focal mechanisms) and geodetic (GPS displacements) data to evaluate the characteristics of the last stages of the kinematic evolution of the arc. The El Salvador Fault Zone constitutes a large band of transtensional deformation whose direction varies between N90°E and N110°E. Its dip is about 70° S because it comes from the reactivation of a previous extensional stage. A protocol consisting of three successive steps was followed to compare the predictions of the model with the natural data. The results show a simple shear direction plunging between 20° and 50° W (triclinic flow) and a kinematic vorticity number that is mostly higher than 0.81 (simple-shearing-dominated flow). The direction of shortening of the coaxial component would be located according to the dip of the deformation band. It was concluded that this type of analytical model could be very useful in the kinematic study of active volcanic arcs, even though only information on small deformation increments is available.

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Active faults of El Salvador

Cited by 6 publications

References 50 publications

Deformation in Western Guatemala Associated With the NAFCA (North America‐Central American Forearc‐Caribbean) Triple Junction: Neotectonic Strain Localization Into the Guatemala City Graben

Deformation in Western Guatemala Associated With the NAFCA (North America‐Central American Forearc‐Caribbean) Triple Junction: Neotectonic Strain Localization Into the Guatemala City Graben

2D FEM Numerical Prediction of Local Seismic Effects at San Salvador Municipality (El Salvador) Induced by 2001 Earthquakes

Active Triclinic Transtension in a Volcanic Arc: A Case of the El Salvador Fault Zone in Central America

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