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Volcán Lascar Volcán Lascar Región: Antofagasta Provincia: El Loa Comuna: San Pedro de Atacama Coordenadas: 21°22’S – 67°44’O Poblados más cercanos: Talabre – Camar – Socaire Tipo: Estratovolcán Altura: 5.592 m s.n.m. Diámetro basal: 8.9 km Área basal: 62.2 km2 Volumen estimado: 28.5 km3 Última actividad: 2015 Última erupción mayor: 1993 Volcán Lascar. Vista desde el norte Ranking de riesgo (Fotografía: Gabriela Jara, SERNAGEOMIN) 14 específico: Generalidades El volcán Láscar corresponde a un estratovolcán compuesto, elongado en dirección este-oeste, activo desde hace unos 240 ka y emplazado en el margen oeste de la planicie altiplánica. Está conformado por lavas andesíticas, que alcanzan más de 10 km de longitud, y por potentes lavas dacíticas que se extienden hasta 5 km, las que fueron emitidas desde los flancos NO a SO. La lava más reciente se estima en 7 mil años de antigüedad. En los alrededores del volcán se reconocen depósitos de flujo y caída piroclástica, además de numerosos cráteres de impacto asociados a la eyección de bombas durante erupciones plinianas y subplinianas. El principal evento eruptivo durante su evolución se denomina Ignimbrita Soncor, generado hace unos 27 ka al oeste del volcán y con un volumen estimado cercano a los 10 km3. En la cima de este volcán se observan seis cráteres, algunos anidados, y el central de estos se encuentra activo. Registro eruptivo Este volcán ha presentado alrededor de 30 erupciones explosivas desde el siglo XIX, lo que lo convierte en el volcán más activo del norte de Chile. Estos eventos han consistido típicamente en erupciones vulcanianas de corta duración, con emisión de ceniza fina y proyecciones balísticas en un radio de 5 km, donde el último evento de este tipo ocurrió el 30 de octubre del 2015. Dentro de este registro destaca la erupción subpliniana del 19-20 de abril de 1993, correspondiente al mayor evento ocurrido en el norte de Chile en tiempos históricos. Asociado a este, se generó un depósito de caída piroclástica que se extendió hacia el NO argentino donde alcanzó espesores inferiores a 1 cm. Asimismo, múltiples flujos piroclásticos pumíceos, relacionados con colapsos parciales de la columna eruptiva, alcanzaron hasta 10 km hacia el norte, noroeste y suroeste del volcán. La actividad actual se caracteriza por la persistente emisión de gases desde el cráter central, con un preponderante componente magmático, y ocasionales explosiones menores de ceniza fina. Peligros y riesgos asociados Son esperables eventos eruptivos de diversa magnitud en el corto y mediano plazo. Las zonas más expuestas corresponden a los flancos norte, oeste y sur del volcán, susceptibles de ser impacatadas por corrientes piroclásticas y proyecciones balísticas. La dispersión atmosférica de material piroclástico pumíceo estaría mayoritariamente dirigida hacia el este y sureste del volcán, con acumulación variable hacia el Paso Huaytuquina y a lo largo de las rutas internacionales CH-27 y CH-23, en las cercanías de los Pasos de Jama y Sico, respectivamente. No obstante, columnas eruptivas altas durante los meses de verano podrían dispersar piroclastos hacia centros poblados ubicados al oeste del volcán, como Toconao, Talabre, Camar, Peine y Socaire. Mapa de ubicación de Volcán Lascar Déruelle, B. 1985. Le Volcan Láscar: Géologie et petrologie. In Congreso Geológico de Chile, No. 4, Actas 3: 120-137. Sparks, R.S.J.; Stasiuk, M.V.; Gardeweg, M.C.; Swanson, D.A. 1993. Welded Breccias in Andesite Lavas. Journal of the Geological Society of London 150: 897-902. Gardeweg, M.C.; Medina, E. 1994. La erupción subpliniana del 19-20 Abril de 1993 del Volcán Láscar, Norte de Chile. In Congreso Geológico Chileno, No. 7, Actas 1: 299-304. Concepción. Gardeweg, M.C.; Fuentealba, G.; Murillo, M.; Petit-Breuilh, M.E.; Espinoza, A.; Moreno, M.; Sparks, R.S.J.; Matthews, S.J. 1994. Volcán Láscar: Geología y Evaluación del Riesgo Volcánico-Altiplano II Región. Informe Registrado IR-1994-3, Servicio Nacional de Geología y Minería: 169 p. Matthews, S.; Jones, A.P.; Gardeweg, M.C. 1994. Lascar volcano, Northern Chile; evidence for steady-state disequilibrium. Journal of Petrology 35: 401-432. Déruelle, B.; Figueroa, O.; Medina, E.; Viramonte, J.; Maragno, M. 1996. Petrology of pumice of April 1993 eruption of Láscar (Atacama, Chile). Terra Nova 8: 191-199. Matthews, S.J.; Marquillas, R.A.; Kemp, A.J.; Grange, F.K.; Gardeweg, M.C. 1996. Active skarn formation beneath Láscar Volcano, Northern Chile: a petrographic and geochemical study of xenoliths in eruptions products. Journal of Metamorphic Geology 14: 509-530. Sparks, R.S.J.; Gardeweg, M.C.; Calder, E.S.; Matthews, S.J. 1997. Erosion by pyroclastic flows on Láscar Volcano, Northern Chile. Bulletin of Volcanology 58: 557-565. Matthews, S.; Gardeweg, M.; Sparks, R. 1997. The 1984 to 1996 cycling activity of Láscar Volcano, northern Chile: cycles of dome growth, dome subsidence, degassing and explosive eruptions. Bulletin of Volcanology 59: 72-82. Gardeweg, M.C.; Sparks, R.S.J.; Matthews, S.J. 1998. Evolution of Láscar Volcano, Northern Chile. Journal of the Geological Society of London 155: 89-104. Hellweg, M. 1999. Seismic signals from Láscar volcano. Journal of South American Earth Sciences 12: 123-133. Matthews, S.J.; Sparks, R.S.J.; Gardeweg, M.C. 1999. The Piedras Grandes-Sóncor event, Láscar Volcano, Chile; evolution of a zoned magma chamber in the Central Andean upper crust. Journal of Petrology 40: 1891-1919. Calder, E.S.; Sparks, R.S.J.; Gardeweg, M. 2000. Erosion, transport and segregation of pumice and lithic clasts in pyroclastic flows inferred from ignimbrites at Láscar Volcano, Chile. Journal of Volcanology and Geothermal Research 104: 201-235. Wörner, G.; Hammerschmidt, K.; Henjes-Kunst, F.; Lezaum, J.; Wilke, H. 2000. Geochronology (Ar-Ar, K-Ar, and He-exposure ages) of Cenozoic magmatic rocks from northern Chile (18-22°S): implications for magmatism and tectonic evolution of the central Andes. Risacher, F.; Alonso, H. 2001. Geochemistry of ash leachates from the 1993 Lascar eruption, northern Chile. Implication for recycling of ancient evaporites. Journal of Volcanology and Geothermal Research 109(4): 319-337. Aguilera, F.; Martínez, C.; Tassi, F.; Viramonte, J.; Medina, E.; Vargas, H. 2003. Actividad del volcán Láscar en el período 2000-2002. In Congreso Geológico Chileno, No. 10, Actas (CD-ROM). Concepción. Aguilera, F. 2004. Monitoreo volcánico a través de sensores reomotos: aplicaciones al volcán Láscar, Segunda Región de Antofagasta, Chile. Memoria para optar al Título de Geólogo. Departamento de Geología, Universidad Católica del Norte: 159 p. Antofagasta. Mather, T.; Tsanev, V.; Pyle, D.; McGonnicle, A.J.S.; Oppenheimer, C.; Allen, A.G. 2004. Characterizatation and evolution of tropospheric plumes from Lascar and Villarrica volcanoes, Chile. Journal of Geophysical Research 109, D21303. Pavez, A.; Legrand, D.; Remy, D.; Diament, M.; Froger, J-L.; Bonvalot, S.; Julien, P.; Moisset, D.; Gabalda, G. 2006. Insight into ground deformations at Láscar volcano (Chile) from SAR interferometry, photogrammetry and GPS data: Implications on volcano dynamics and future space monitoring. Remote Sensing and Environment 100: 307-320. 307-320.Tassi, F.; Aguilera, F.; Vaselli, O.; Medina, E.; Tedesco, D.; Delgado-Huertas, A.; Poreda, R.; Kojima, S. 2009. The magmatic- and hydrothermal-dominated fumarolic system at the Active Crater of Láscar volcano, northern Chile. Bulletin of Volcanology 71: 171-183. Aguilera, F. 2010. Sobre el origen, naturaleza y evolución de los fluidos en volcanes, campos geotérmicos y fuentes termales de la Zona Volcánica Central (ZVC) en el norte de Chile (17°43’S – 25°10’S). Concurso Bicentenario, Tesis Doctorales 2008, Vol. I: 161-468, Andros Impresores S.A., Santiago. ISBN: 978-956-7892-31-0. Díaz, D.; Brasse, H.; Ticona, F. 2012. Conductivity distribution beneath Lascar volcano (Northern Chile) and the Puna, inferred from magnetotelluric data. Journal of Volcanology and Geothermal Research 217-218: 21-29. Whelley, P.L.; Jay, J.; Calder, E.S.; Pritchard, M.E.; Cassidy, N.J.; Alcaraz, S.; Pavez, A. 2012. Post-depositional fracturing and subsidence of pumice flow deposits: Lascar Volcano, Chile. Bulletin of Volcanology 74(2): 511-531. Jay, J.A.; Welch, M.; Pritchard, M.E.; Mares, P.J.; Mnich, M.E.; Melkonian, A.K.; Aguilera, F.; Naranjo, J.A.; Sunagua, M.; Clavero, J.E. 2013. Volcanic hotspots of the central and southern Andes as seen from space by ASTER and MODVOLC between the years 2000 and 2010. Geological Society of London Special Publications 380(1): 161-185. Pritchard, M.E.; Henderson, S.T.; Jay, J.A.; Soler, V.; Krzesni, D.A.; Button, N.E.; Welch, M.D.; Semple, A.G.; Glass, B.; Sunagua, M.; Minaya, E.; Amigo, A.; Clavero, J.E. 2014. Reconnaissance earthquake studies at nine volcanic areas of the central Andes with coincident satellite thermal and InSAR observations. Journal of Volcanology and Geothermal Research 280: 90-103. Información Cartográfica: Ramírez, C.F.; Gardeweg, M. 1982. Geología de la Hoja Toconao, Región de Antofagasta, escala 1:250.000. Instituto de Investigaciones Geológicas, Carta Geológica de Chile 54: 122, 1 mapa. Santiago. Gardeweg, M.C.; Amigo, A.; Matthews, S..J.; Sparks, R.S.J.; Clavero, J.E. 2011. Geología del volcán Láscar, Región de Antofagasta. Servicio Nacional de Geología y Minería, Carta Geológica de Chile, Serie Geología Básica 131: 40 p., 1 mapa escala 1:50.000. Santiago. Amigo, A., Bertin, D., Orozco, G. 2012. Peligros volcánicos de la zona norte de Chile, Regiones de Arica y Parinacota, Tarapacá, Antofagasta y Atacama. Servicio Nacional de Geología y Minería, Carta Geológica de Chile, Serie Geología Ambiental 17: 45 p., 1 mapa en 5 hojas escala 1:250.000, 1 mapa escala 1:3.000.000. Santiago. Gardeweg, M.C.; Amigo, A. 2015. Peligros del volcán Láscar, Región de Antofagasta. Servicio Nacional de Geología y Minería, Carta Geológica de Chile, Serie Geología Ambiental 22, 1 mapa escala 1:50.000.
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