Active deformation in the San Salvador extensional stepover, El Salvador from an analysis of the April–May 2017 earthquake sequence and GPS data

Legrand, D.; Marroquín, Griselda; DeMets, Charles; Mixco, Luis; García, Andrés Carrión; Villalobos, Montserrat Prada; Ferrés, Dolors; Gutiérrez, Eduardo; Escobar, Demetrio; Torres, Rodolfo; Hernández, Daniela

doi:10.1016/j.jsames.2020.102854

Cited by 10 publications

(20 citation statements)

References 49 publications

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“…Furthermore, our data suggests that its slip rate is probably lower than the 8 mm/yr estimated by Staller et al (2016). This is consistent with the recent results of Legrand et al (2020) on the San Salvador graben, which proposes that most of the deformation is accumulated further south from the Guaycume fault.…”

Section: Discussionsupporting

confidence: 91%

“…However, its precise behaviour is far from being known. The slip rates assigned in past studies vary significantly: Staller et al (2016) estimate a slip rate of 8 mm/yr, while Legrand et al (2020) suggest that most of the deformation is accumulating further south. New GNSS stations installed on the area (Fig.…”

Section: Introductionmentioning

confidence: 99%

“…The earthquakes originated on faults within the volcanic arc pose a great danger to the population of El Salvador, due to their shallow depths, proximity to urban areas and frequency (Legrand et al 2020). Understanding the kinematics and behaviour of the individual faults is key for assessing the seismic hazard in the country.…”

Section: Introductionmentioning

confidence: 99%

“…Alonso-Henar et al 2015;Canora et al 2012), many incorporating GNSS observations (e.g. Alvarado et al 2011;Ellis et al 2018;Legrand et al 2020;Staller et al 2016). Although most of these studies have a regional scale, covering broader areas in Central America (Alvarado et al 2011;Correa-Mora et al 2009;Ellis et al 2018;Ellis et al 2019;Lyon-Caen et al 2006;Rodríguez et al 2009), some focus on the ZFES (Canora et al 2014;Garibaldi et al 2016;Staller et al 2016), or specific segments (Legrand et al 2020).…”

Section: Introductionmentioning

confidence: 99%

“…Alvarado et al 2011;Ellis et al 2018;Legrand et al 2020;Staller et al 2016). Although most of these studies have a regional scale, covering broader areas in Central America (Alvarado et al 2011;Correa-Mora et al 2009;Ellis et al 2018;Ellis et al 2019;Lyon-Caen et al 2006;Rodríguez et al 2009), some focus on the ZFES (Canora et al 2014;Garibaldi et al 2016;Staller et al 2016), or specific segments (Legrand et al 2020). In contrast to the relative abundance of GNSS studies, InSAR studies on the area are very limited in number, consisting mostly of regional-scale volcanic studies (e.g.…”

Section: Introductionmentioning

confidence: 99%

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Towards a Precise Modelling of the El Salvador Fault Zone Using Geodetic Techniques

Portela

Staller

Béjar‐Pizarro

2021

Proceedings - 3rd Congress in Geomatics Engineering - CIGeo

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The El Salvador Fault Zone (ESFZ) comprises a set of a strike-slip faults, extending through the Central American VolcanicArc within El Salvador, where the Cocos plate subducts under the Caribbean plate. These structures act as a boundarybetween the forearc sliver and the western margin of the Chortís block, accommodating the relative movement betweenthem. The ESFZ has been responsible for several shallow, destructive earthquakes in El Salvador, thus posing a seriousthreat for millions of inhabitants. Understanding its seismic potential and the behaviour of its different segments results ofgreat importance for the assessment and mitigation of seismic risk in the region. Geodetic techniques, such as GNSS andInSAR, are useful tools for measuring surface deformation related to tectonic activity. We are in the process of updatingand densifying the existing GNSS velocity field in El Salvador, aiming to characterise the individual faults in the region bydetermining their slip rates and locking depth. Additionally, we will process InSAR data, trying to obtain a continuousmeasurement of the interseismic deformation. The combination of this information with other data (e.g. seismological andgeological) through kinematic models will allow us to better understand the factors controlling the seismogenic behaviourof the ESFZ faults, evaluate their seismic potential and improve the seismic hazard assessment.

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Section: Discussionsupporting

confidence: 91%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Towards a Precise Modelling of the El Salvador Fault Zone Using Geodetic Techniques

Portela

Staller

Béjar‐Pizarro

2021

Proceedings - 3rd Congress in Geomatics Engineering - CIGeo

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Seismic evidence of the active regional tectonic faults and the Copahue volcano, at Caviahue Caldera, Argentina

et al. 2021

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Understanding interactions between tectonic faults and a nearby active volcano is often realized by combining seismic and field observations. A good example of such an interaction is the Caviahue caldera. It is located in an intra-arc extensional pull-apart basin, within a transition zone joining the northern part of the right-lateral strike-slip Liquiñe-Ofqui Fault System and the thrustfault Antiñir-Copahue fault zone. Most of the active volcanoes in South Chile are related to the Liquiñe-Ofqui Fault System. Some faults located inside the Caviahue caldera were described with reverse mechanisms by some studies whereas they were found to be normal by others. In order to discriminate the actual focal mechanisms, two seismic clusters that occurred in 2017 and 2018 inside the Caviahue rectangular caldera, close to the active Copahue volcano, were studied. Earthquakes (520) were located; focal mechanisms (56) were determined from which an average seismic moment tensor was calculated. The locations and focal mechanisms of the earthquakes allow splitting the seismicity into two main regions, one of tectonic origin (with strike-slip faults) and another one of volcanic origin (with normal faults). The first seismic cluster is located close to Caviahue village, with strikeslip focal mechanisms, in an NNE direction as the nearby Liquiñe-Ofqui Fault strikes. The other part of the seismicity is located close to the northeastern structures of Copahue volcano, in the hydrothermal zone of Anfiteatro, Termas de Copahue, and Maquinitas. It is oriented in an NE direction and is composed of earthquakes with normal focal mechanisms, not reverse as postulated in past studies. The active Copahue volcano lies in the SW prolongation of these normal faults, in agreement with the tectonics of the Caviahue caldera. Then, the two nearby seismic clusters reveal both a tectonic origin, with strike-slip focal mechanisms compatible with the Liquiñe-Ofqui Fault System, and a hydrothermal origin with normal focal mechanisms, compatible with the hydrothermal system of the Copahue active volcano.

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Active faults of El Salvador

Martínez‐Díaz

Álvarez‐Gómez

Staller

et al. 2021

Journal of South American Earth Sciences

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Active deformation in the San Salvador extensional stepover, El Salvador from an analysis of the April–May 2017 earthquake sequence and GPS data

Cited by 10 publications

References 49 publications

Towards a Precise Modelling of the El Salvador Fault Zone Using Geodetic Techniques

Towards a Precise Modelling of the El Salvador Fault Zone Using Geodetic Techniques

Seismic evidence of the active regional tectonic faults and the Copahue volcano, at Caviahue Caldera, Argentina

Active faults of El Salvador

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