Source characterization of the San Juan (Argentina) crustal earthquakes of 15 January 1944 (Mw 7.0) and 11 June 1952 (Mw 6.8)

Alvarado, Patricia; Beck, S. L.

doi:10.1016/j.epsl.2006.01.015

Cited by 62 publications

(73 citation statements)

References 28 publications

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“…The most likely explanation for the architecture of this fault relates to the superimposition of the deformation onto the Salta Rift province. The combination of horizontal stresses (e.g., Jordan et al, 1983;Alvarado and Beck, 2006) and these preexisting zones of weakness in the Sierras de Pampeanas (e.g., Mon and Salfi ty, 1995;Schmidt et al, 1995;Ramos et al, 2002;Cristallini et al, 2004) and the neighboring Eastern Cordillera Grier et al, 1991;Hongn and Seggiaro, 2001) has favored the widely distributed reactivation of extensional structures.…”

Section: Discussionmentioning

confidence: 97%

Fragmentation of a foreland basin in response to out-of-sequence basement uplifts and structural reactivation: El Cajon-Campo del Arenal basin, NW Argentina

Mortimer

Carrapa

Coutand³

et al. 2007

Geological Society of America Bulletin

139

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The style and mechanisms by which a foreland region is incorporated into an orogen depends on the tectonic style, effectiveness of uplift, and dynamic subsidence. Classical foreland-basin models refl ect a self-similar propagation of deformation into the foreland in a thin-skinned thrust-belt setting governed by wedge mechanics. Thick-skinned foreland regions, which are characterized by high-angle reverse-fault-bounded basement uplifts and intervening basins, however, do not fi t this idealized model. Unlike thinskinned tectonic provinces, deformation and uplift in these regions may be highly variable in time and space. Furthermore, deformation patterns may be complicated by the presence of preexisting structures, particularly those which lie at orientations that enable them to be reactivated and utilized to accommodated deformation under compression.The Neogene El Cajón-Campo del Arenal basin is one of a series of basins located along the eastern margin of the Puna Plateau within the Sierras Pampeanas, a region that is composed of a thick-skinned foreland fragmented by reverse-fault-bounded basement uplifts that regionally characterize an eastward-younging trend. This region is superimposed onto the Cretaceous Salta Rift province, which provides a series of preexisting structures that may potentially be reactivated. The basin is located along the eastern margin of the Puna Plateau, an integral component of the Andean orogen, which includes several fi lled, uplifted, and internally drained Cenozoic intraplateau basins. Structural and sedimentological similarities exist between basins along the margin of the Puna and those within it. Understanding the evolution of foreland basins, such as the El Cajón-Campo del Arenal basin, provides possible mechanisms for the development and incorporation of marginal basins into orogenic belts, and in the case of the Andean orogen, the potential for these basins to be incorporated into the plateau.Our analysis, which integrates seismic, sedimentary, and thermochronological data, characterizes the evolution of this basin and surrounding ranges. The appearance in the sedimentary section of a distinct grain-age population derived from the basement erosion surface constrains the uplift and erosion of an out-of-sequence intrabasin high to ca. 6 Ma. The basin fi ll, therefore, records an evolution from an undeformed foreland to one that is compartmentalized by basement uplifts and that is incorporated into the greater orogenic structure. The data reveal the importance of the reactivation of preexisting structures along the basin margin in creating east-dipping structures in a generally west-dipping domain. These opposing faults on the basin margin consequently caused the out-of-sequence uplift of the intrabasin range, the Sierra de Quilmes. The Sierra de Quilmes fragments the foreland and, because its position is locked by loads to the west and east, creates increased deformation within the basin, basin fi ll, uplift, and incorporation into the orogen. Unlike basins within the plateau...

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Section: Discussionmentioning

confidence: 97%

Fragmentation of a foreland basin in response to out-of-sequence basement uplifts and structural reactivation: El Cajon-Campo del Arenal basin, NW Argentina

Mortimer

Carrapa

Coutand³

et al. 2007

Geological Society of America Bulletin

139

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“…However the most significant examples of damaging earthquakes (1861, 1894, 1944, 1977 and 1985) are the events in the crust (depth < 35 km) of the Andean retroarc over the flat-slab subduction segment at about 31 • S ( KadinskyCade, 1985;Langer and Bollinger, 1988;Langer and Hartzell, 1996;Alvarado and Beck, 2006;INPRES, 2010). The study of the largest earthquakes in San Juan using teleseismic data has revealed predominantly reverse focal mechanisms but different crustal depths of their sources (Chinn and Isacks, 1983;Kadinsky-Cade, 1985;Langer and Hartzell, 1996;Alvarado and Beck, 2006). These events are associated with the shortening in the thick-skinned Sierras Pampeanas and their interaction with the frontal part of the thinskinned Precordillera fold and thrust belt (Fig.…”

Section: Introductionmentioning

confidence: 98%

Earthquake deformation in the northwestern Sierras Pampeanas of Argentina based on seismic waveform modelling

Alvarado

Ramos

2011

Journal of Geodynamics

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“…These types of processes, being observed up to 400 km from the epicentre zone of the 1894 earthquake, affected an area of 110 000 km 2 (Pérez & Costa 2012). Historically, a magnitude 8.2 was assigned to this event, being later reduced according to the length of the fault rupture to M s 7.5 (Bastías 1985;Castano 1993), M s 8 (Alvarado et al 2005) and M s 7.6 (Alvarado & Beck 2006). However, documented ground seismic effects led to an assignment of M s c. 8 for this extraordinary event.…”

Section: Ground Seismic Effectsmentioning

confidence: 99%

“…The hypocentre of the earthquake of 15 January 1944 (La Laja, San Juan; M s 7.4) was located at 11 km depth (Alvarado et al 2005;Alvarado & Beck 2006) and associated with La Laja fault in the eastern Precordillera system. It reached an intensity of IX (MM) and resulted in 6000-10 000 fatalities and the destruction of 80 per cent of homes.…”

Section: Historical Records and Damagementioning

confidence: 99%

Historical damage and earthquake environmental effects related to shallow intraplate seismicity of central western Argentina

Moreiras

Páez

2014

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Central western Argentina is identified as the most hazardous seismic zone in the country. Historical earthquakes with magnitudes greater than M s . 6.0 frequently occur in this territory and are associated with the subduction of the Nazca plate. However, seismic hazards have not been fully assessed in this region. No secondary seismic effects of a potential earthquake with destructive consequences have been considered, nor has the existence of shallow Quaternary blind faults been identified by seismic surveys. Neotectonic studies performed up to the present describe only those Quaternary faults with some surficial expression. Lacking proper hazard assessment limits strategies to reduce the economic impact of drastic seismic events. This chapter is focused on the impact of major destructive earthquakes that have occurred in central western Argentina in order to understand the incidence of these phenomena in the past and to consider the vulnerability of the region in light of its increased urbanization and changing agricultural practices.

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Source characterization of the San Juan (Argentina) crustal earthquakes of 15 January 1944 (Mw 7.0) and 11 June 1952 (Mw 6.8)

Cited by 62 publications

References 28 publications

Fragmentation of a foreland basin in response to out-of-sequence basement uplifts and structural reactivation: El Cajon-Campo del Arenal basin, NW Argentina

Fragmentation of a foreland basin in response to out-of-sequence basement uplifts and structural reactivation: El Cajon-Campo del Arenal basin, NW Argentina

Earthquake deformation in the northwestern Sierras Pampeanas of Argentina based on seismic waveform modelling

Historical damage and earthquake environmental effects related to shallow intraplate seismicity of central western Argentina

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