Triggered seismicity in the Andean arc region via static stress variation by the MW = 8.8, February 27, 2010, Maule earthquake |
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| Affiliation: | 1. Departamento de Física, Universidad Nacional de San Luis, Ejército de los Andes 950, 5700, San Luis, Argentina;2. Instituto Geofísico-Sismológico Ing. F. S. Volponi, Universidad Nacional de San Juan, Ruta 12, Km 17, CP 5407, San Juan, Argentina;3. IANIGLIA-CCT, Mendoza-CONICET, Argentina;1. Instituto de Química, Universidade de Brasília, 70904-970 Brasília, DF, Brazil;2. Instituto de Química, Universidade Federal de Mato Grosso do Sul, 79074-460 Campo Grande, MS, Brazil;1. Department of Chemistry, Banaras Hindu University, Varanasi 221005, India;2. Department of Chemistry, Kirori Mal College, University of Delhi, Delhi 110007, India;3. Department of Chemistry, Indian Institute of Technology, Roorkee, Uttarakhand 247667, India;1. Department of Plant Physiology, University of Agriculture in Krakow, Podłużna 3, 30-239 Kraków, Poland;2. Institute of Plant Physiology, Polish Academy of Sciences, Niezapominajek 21, 30-239 Kraków, Poland;1. Universidad Nacional Autónoma de México, Instituto de Geología, Departamento de Paleontología, México D.F., 04510, Mexico;2. ENSAYA Laboratorio, Aneto 8, Cuarte de Huerva, Zaragoza, 50410, Spain;3. Universidad de Granada, Departamento de Estratigrafía y Paleontología, Av. Fuentenueva s/n, Granada 18071, Spain;1. Department of Physics, Section of Solid State Physics, University of Athens, Panepistimiopolis, GR-15784, Zografos, Athens, Greece;2. Department of Electronics Engineering, Technological Education Institute (TEI) of Piraeus, 250 Thivon & P. Ralli, GR-12244, Aigaleo, Athens, Greece |
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| Abstract: | 
We localized crustal earthquakes in the Andean arc, between 35°S and 36°S, from December 2009 to May 2010. This research shows a seismicity increase, in a narrow longitudinal area, of more than nine times after the great Mw 8.8 Maule earthquake.The localized seismicity defines an area of ∼80 km long and ∼18 km wide and NNW to NNE trend. The Md magnitudes varied from 0.7 to 3.1 except for two earthquakes with Mw of 3.9 and 4.5, located in the northern end of the area. The focal mechanisms for these two last events were normal/strike-slip and strike-slip respectively.During 2011, a network of 13 temporary stations was installed in the trasarc region in Malargüe, Argentina. Sixty earthquakes were localized in the study region during an 8 month period.We explored how changes in Coulomb conditions associated with the mega-thrust earthquake triggered subsequent upper-plate events in the arc region. We assumed the major proposed structures as receiver faults and used previously published earthquake source parameters and slip distribution for the Maule quake. The largest contribution to static stress change, up to 5 bars, derives from unclamping resulting consistent with co-seismic dilatational deformation inferred from GPS observations in the region and subsidence in nearby volcanoes caused by magma migration.Three different Quaternary tectonic settings–extensional, strike-slip and compressional-have been proposed for the arc region at these latitudes. We found that the unclamping produced by the Maule quake could temporarily change the local regime to normal/strike-slip, or at least it would favor the activation of Quaternary NNE to N-trending dextral strike-slip faults with dextral transtensional movement. |
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| Keywords: | Triggered seismicity Static stress variation Andean arc region |
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