Browsing by Author "Ramos Palomino, Domingo A."
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Item Open Access Actividad sismo-volcánica asociada a la erupción del volcán Ubinas en 2006-2008(XIV Congreso Peruano de Geología, 2008) Macedo Sánchez, Orlando Efraín; Métaxian, Jean-Philippe; Taipe, Edu; Ramos Palomino, Domingo A.El 25 de marzo 2006, pobladores del valle situado al SE del volcán Ubinas (16º 22’ S, 70º 54’ W; 5672 m) alertan sobre rugidos provenientes del volcán y de caída de cenizas sobre sus sembríos. Este volcán, considerado como el más activo del Perú en los últimos 500 años, había entrado nuevamente en erupción, amenazando a más de 3500 pobladores que habitan en el valle del río Ubinas. El Instituto Geofísico del Perú (IGP) en cooperación con el Institut de Recherche pour le Developpement (IRD-France) ha efectuado el monitoreo y la vigilancia de la actividad sísmica asociada al proceso eruptivo, primero mediante 2 estaciones sísmicas digitales de banda ancha y posteriormente mediante una red de hasta cuatro estaciones sísmicas digitales (3 de 1 Hz y una de banda ancha), las cuales transmiten los datos hasta el Observatorio Volcanológico de Cayma en Arequipa. Presentamos las principales características de la evolución de la sismicidad observada, usando los datos de a red sísmica radio-telemétrica. Anteriormente, durante tres semanas en marzo-abril 1998 (Taipe, 2008), se realizó un monitoreo sísmico mediante una red de 6 estaciones sísmicas digitales RefTek equipadas con 2 sismómetros digitales 3C de banda ancha y otros 4 sismómetros 3C de periodo corto desplegados sobre todo el edificio. Estos estudios determinaron la existencia de una importante sismicidad (Fig 1) caracterizada por diverso tipo de sismos asociados a fracturas (VT) y paso de fluidos (LP, tremores y tornillos) en las inmediaciones del cono.Item Restricted Asymmetrical structure, hydrothermal system and edifice stability: The case of Ubinas volcano, Peru, revealed by geophysical surveys(Elsevier, 2014-04) Gonzales, Katherine; Finizola, Anthony; Lénat, Jean-François; Macedo Sánchez, Orlando Efraín; Ramos Palomino, Domingo A.; Thouret, Jean-Claude; Fournier, Michel; Cruz, Vicentina; Pistre, KarineUbinas volcano, the historically most active volcano in Peru straddles a low-relief high plateau and the flank of a steep valley. A multidisciplinary geophysical study has been performed to investigate the internal structure and the fluids flow within the edifice. We conducted 10 self-potential (SP) radial (from summit to base) profiles, 15 audio magnetotelluric (AMT) soundings on the west flank and a detailed survey of SP and soil temperature measurements on the summit caldera floor. The typical “V” shape of the SP radial profiles has been interpreted as the result of a hydrothermal zone superimposed on a hydrogeological zone in the upper parts of the edifice, and depicts a sub-circular SP positive anomaly, about 6 km in diameter. The latter is centred on the summit, and is characterised by a larger extension on the western flank located on the low-relief high plateau. The AMT resistivity model shows the presence of a conductive body beneath the summit at a depth comparable to that of the bottom of the inner south crater in the present-day caldera, where intense hydrothermal manifestations occur. The lack of SP and temperature anomalies on the present caldera floor suggests a self-sealed hydrothermal system, where the inner south crater acts as a pressure release valve. Although no resistivity data exists on the eastern flank, we presume, based on the asymmetry of the basement topography, and the amplitude of SP anomalies on the east flank, which are approximately five fold that on the west flank, that gravitational flow of hydrothermal fluids may occur towards the deep valley of Ubinas. This hypothesis, supported by the presence of hot springs and faults on the eastern foot of the edifice, reinforces the idea that a large part of the southeast flank of the Ubinas volcano may be altered by hydrothermal activity and will tend to be less stable. One of the major findings that stems from this study is that the slope of the basement on which a volcano has grown plays a major role in the geometry of the hydrothermal systems. Another case of asymmetrical composite cone edifice, built on a steep topography, is observed on El Misti volcano (situated 70 km west of Ubinas), which exhibits a similar SP pattern. These types of edifices have a high potential of spreading and sliding along the slope owing to the thicker accumulation of low cohesion and hydrothermally altered volcanic products.Item Open Access Estudio estructural y del sistema hidrotermal de los volcanes Sabancaya y Hualca-Hualca mediante el método de Potencial Espontáneo(Instituto Geológico, Minero y Metalúrgico - INGEMMET, 2018) Puma Sacsi, Nino; Macedo Sánchez, Orlando Efraín; Álvarez, Yovana; Finizola, Anthony; Ramos Palomino, Domingo A.El volcán Sabancaya, considerado el segundo volcán más activo del Perú forma parte del complejo Volcánico Ampato-Sabancaya (CVAS), está ubicado a 80 Km en dirección NNO de la ciudad de Arequipa (15°47’ S; 71°72’W; 5976 msnm) en el sur del Perú. El presente estudio tiene como finalidad determinar estructuras importantes que se encuentran ocultas por material volcánico y el efecto que generan estas estructuras sobre la señal del Potencial Espontaneo (PE); además, estudiar el sistema hidrotermal del volcán Sabancaya, aplicando uno de los métodos geofísicos más antiguos y conocidos, pero poco usado en la vulcanología, como es el PE. La aplicación de este método nos ha permitido conocer la estructura interna del área del CVAS y volcán Hualca-Hualca, así como determinar las dimensiones del sistema hidrotermal.Item Restricted Fluid circulation and structural discontinuities inside Misti volcano (Peru) inferred from self-potential measurements(Elsevier, 2004-08) Finizola, Anthony; Lénat, Jean-François; Macedo Sánchez, Orlando Efraín; Ramos Palomino, Domingo A.; Thouret, Jean-Claude; Sortino, FrancescoOne of the seven potentially active andesite stratovolcanoes in southern Peru, Misti (5822 m), located 17 km northeast and 3.5 km above Arequipa, represents a major threat to the population (∼900,000 inhabitants). Our recent geophysical and geochemical research comprises an extensive self-potential (SP) data set, an audio – magnetotelluric (AMT) profile across the volcano and CO2 concentrations in the soil along a radial profile. The SP survey is the first of its kind in providing a complete mapping of a large andesitic stratovolcano 20 km in diameter. The SP mapping enables us to analyze the SP signature associated with a subduction-related active volcano. The general SP pattern of Misti is similar to that of most volcanoes with a hydrogeologic zone in the lower flanks and a hydrothermal zone in the upper central area. A quasi-systematic relationship exists between SP and elevation. Zones with constant SP/altitude gradients (Ce) are observed in both hydrogeologic (negative Ce) and hydrothermal (positive Ce) zones. Transition zones between the different Ce zones, which form a concentric pattern around the summit, have been interpreted in terms of lateral heterogeneities in the lithology. The highest amplitudes of SP anomalies seem to coincide with highly resistive zones. The hydrothermal system 6 km in diameter, which extends over an area much larger than the summit caldera, may be constrained by an older, concealed collapse caldera. A sealed zone has apparently developed through alteration in the hydrothermal system, blocking the migration of CO2 upward. Significant CO2 emanations are thus observed on the lower flanks but are absent above the hydrothermal zone.Item Restricted Influence of the regional topography on the remote emplacement of hydrothermal systems with examples of Ticsani and Ubinas volcanoes, Southern Peru(Elsevier, 2013-03) Byrdina, Svetlana; Ramos Palomino, Domingo A.; Vandemeulebrouck, Jean; Masias, Pablo; Revil, André; Finizola, Anthony; Gonzales Zuñiga, Katherine; Cruz, Vicentina; Antayhua Vera, Yanet Teresa; Macedo Sánchez, Orlando EfraínPresent work studies the influence of the regional topography on the hydrothermal fluid flow pattern in the subsurface of a volcanic complex. We discuss how the advective transfer of heat from a magmatic source is controlled by the regional topography for different values of the averaged permeability. For this purpose, we use a 2-D numerical model of coupled mass and heat transport and new data sets acquired at Ticsani and Ubinas, two andesitic volcanoes in Southern Peru which have typical topography, justifying this approach. A remarkable feature of these hydrothermal systems is their remote position not centered on the top of the edifice. It is evidenced by numerous hot springs located in more than 10 km distance from the top of each edifice. Upwelling of thermal water is also inferred from a positive self-potential anomaly at the summit of the both volcanoes, and by ground temperatures up to 37 °C observed at Ticsani. Our model results suggest that the regional topographic gradient is able to significantly divert the thermal water flow and can lead to an asymmetric emplacement of the hydrothermal system even considering a homogeneous permeability of the edifice. Inside the thermal flow, the hydraulic conductivity increases with the decrease of temperature-related viscosity, focusing the flow towards the surface and creating a hydrothermal zone at a large lateral distance from the heat source. The location and temperature of the hot springs together with the water table position given by self-potential data can be used to constrain the average permeability of the edifice, a key parameter influencing fluid flow and associated advective heat transfer in the direction opposite to the regional topographic gradient. Our study allows to explain the emplacement of the hydrothermal systems at volcanoes with asymmetric edifices or even the absence of a shallow hydrothermal system. These results can be generalized to the study of non-volcanic hydrothermal systems.Item Restricted Magma extrusion during the Ubinas 2013-2014 eruptive crisis based on satellite thermal imaging (MIROVA) and ground-based monitoring(Elsevier, 2015-09) Coppola, Diego; Macedo Sánchez, Orlando Efraín; Ramos Palomino, Domingo A.; Finizola, Anthony; Delle Done, Dario; Del Carpio Calienes, José Alberto; White, Randall; McCausland, Wendy; Centeno Quico, Riky; Rivera, Marco; Apaza, Fredy; Ccallata, Beto; Chilo, Wilmer; Cigolini, Corrado; Laiolo, Marco; Lazarte, Ivonne; Machaca, Roger; Masias, Pablo; Ortega, Mayra; Puma Sacsi, Nino; Taipe, EduAfter 3 years of mild gases emissions, the Ubinas volcano entered in a new eruptive phase on September 2nd, 2013. The MIROVA system (a space-based volcanic hot-spot detection system), allowed us to detect in near real time the thermal emissions associated with the eruption and provided early evidence of magma extrusion within the deep summit crater. By combining IR data with plume height, sulfur emissions, hot spring temperatures and seismic activity, we interpret the thermal output detected over Ubinas in terms of extrusion rates associated to the eruption. We suggest that the 2013–2014 eruptive crisis can be subdivided into three main phases: (i) shallow magma intrusion inside the edifice, (ii) extrusion and growing of a lava plug at the bottom of the summit crater coupled with increasing explosive activity and finally, (iii) disruption of the lava plug and gradual decline of the explosive activity. The occurrence of the 8.2 Mw Iquique (Chile) earthquake (365 km away from Ubinas) on April 1st, 2014, may have perturbed most of the analyzed parameters, suggesting a prompt interaction with the ongoing volcanic activity. In particular, the analysis of thermal and seismic datasets shows that the earthquake may have promoted the most intense thermal and explosive phase that culminated in a major explosion on April 19th, 2014. These results reveal the efficiency of space-based thermal observations in detecting the extrusion of hot magma within deep volcanic craters and in tracking its evolution. We emphasize that, in combination with other geophysical and geochemical datasets, MIROVA is an essential tool for monitoring remote volcanoes with rather difficult accessibility, like those of the Andes that reach remarkably high altitudes.Item Restricted Physical impacts of the CE 1600 Huaynaputina eruption on the local habitat: geophysical insights(Presses universitaires Blaise Pascal, Clermont-Ferrand, 2018-04) Finizola, A.; Macedo Franco, Luisa Diomira; Antoine, R.; Thouret, J.-C.; Delcher, E.; Bacri, C.; Fauchard, C.; Gusset, R.; Japura, S.; Lazarte, I.; Mariño Salazar, Jersy; Normier, A.; Ramos Palomino, Domingo A.; Saintenoy, T.; Thouret, L.; Del Carpio Calienes, José Alberto; Puma Sacsi, Nino; Macedo Sánchez, Orlando EfraínEl impacto climático global de la erupción del volcán Huaynaputina (IEV6) en 1600 está bien documentado pero las consecuencias regionales sobre las construcciones y los habitantes están poco conocidas. La localización de varios pueblos sepultados bajo los depósitos espesos del Huaynaputina no es claramente mencionada en las crónicas españolas. Investigaciones geofísicas realizadas durante el periodo 2015-2016 sobre diferentes sitios de ruinas a menos de 16 km del cráter constituyen la parte inicial de un proyecto denominado “Huayruro”, cuyo objetivo es entender mejor los impactos físicos y socio-económicos de esta erupción. Varios métodos e instrumentos geofísicos fueron utilizados: un drone y modelos numéricos de terreno de alta resolución, un geo-radar con imágenes 3D del subsuelo, el magnetismo, las imágenes infrarojas y el electro-magnetismo. Esta investigación geofísica preliminar ha permitido identificar la futura estrategia y la mejor instrumentación para cartografiar el área del antiguo pueblo enterrado de Calicanto, localizando con precisión su extensión y los muros de las habitaciones. Este mapeo servirá para los futuros estudios tefro-estratigráficos y arqueológicos. El objetivo final del proyecto es diseminar los resultados del estudio multidisciplinar al público incluyendo la creación de un museo de sitio.Item Open Access Physical impacts of the CE 1600 Huaynaputina eruption on the local habitat: geophysical insights(Sociedad Geológica del Perú, 2017-11) Finizola, Anthony; Macedo Franco, Luisa Diomira; Antoine, Raphael; Thouret, Jean-Claude; Delcher, Eric; Fauchard, Cyrille; Gusset, Rachel; Japura Paredes, Saida Blanca; Lazarte Zerpa, Ivonne Alejandra; Mariño Salazar, Jersy; Ramos Palomino, Domingo A.; Saintenoy, Thibault; Thouret, Liliane; Chávez, José Antonio; Chijcheapaza, Rolando; Del Carpio Calienes, José Alberto; Perea, Ruddy; Puma Sacsi, Nino; Macedo Sánchez, Orlando Efraín; Torres Aguilar, José Luis; Vella, Marc-AntoineThe February-March CE 1600 eruption of Huaynaputina (VEI 6) has a well-documented worldwide climatic impact but the regional consequences of this eruption on climate, habitat and inhabitants are poorly known. The location of several villages buried below the Huaynaputina erupted deposits exceeding one meter in thickness is not clearly mentioned in the historical early Spanish chronicles. Geophysical investigations carried out during the20 15-2016 period on three different sites (Coporaque, Calicanto and Chimpapampa within 16 km from the volcano summit/crater) are the initial stage and part of a large project termed <Item Open Access Seismic monitoring of 2006 Ubinas volcano eruption(EGU General Assembly, 2007) Macedo Sánchez, Orlando Efraín; Métaxian, J-P.; Ramos Palomino, Domingo A.; Araujo, S.; Taipe, EduAt the end of March 2006, Ubinas volcano (16.355º S, 70.903º W, 5672 m) considered the most active volcano of Peru during the last 450 years begun a new eruption process which is lasting until present. The Geophysical Institute of Peru (IGP) with the cooperation of the Institut de Recherche pour le Developpement (IRD-France) has carried out the monitoring and surveillance of seismic activity associated to this eruptive process, at the beginning by 2 digital broadband portable seismic stations and later by a network of 3 digital 1Hz stations which data is transmitted by radio telemetry to Cayma Volcanological Observatory at Arequipa city. Here we present the main characteristics about the evolution of the seismicity during this eruptive process that permitted to us to distinguish, considering also the terrain observations, that there were 4 stages during the process: (1) From March 25th to June 24th : Setting up of intrusive system, openning of the eruptive conduits. During this stage the magma arrive for the first time to the surface on April 19th. The seismic signal includes a few tremors, but they increase with the time. It take place strong explosions with LP precursor events (2) From June 24th to July 16th: Open system functioning, weak flow. Seismic signal have some tremor but the explosions are numerous --until 3 par day—and they do not show LP precursor events anymore. (3) From July 16th to august 31st: Increase of eruptive flow. Seismic signals show a remarkable increase in the last of tremors and especially in their amplitude. The energy of explosions rise and LP precursors appear again. (4) From September to January: probable end of the intrusive episode; magma volume depletion. The intrusion stopped and residual magma remains surrounding the crater area. There are some phreatomagmatic explosions because rainy season. The seismic signals show very few explosions and tremors. The number of LP decrease also, and the daily cumulated energy fall down. The precursor LP events, which precede numerous explosions, were analyzed and used for to emit explosion warnings communicated to the civil protection authorities.