Estudio estructural y del sistema hidrotermal de los volcanes Sabancaya y Hualca-Hualca mediante el método de Potencial Espontáneo

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

The Huayruro Project: mapping the Calicanto Inca area buried by the A.D. 1600 Huaynaputina eruption, with geophysical imaging and remote sensing

We present geophysical and remote sensing observations near the Quinistaquillas town (southern Peru), in the framework of the HUAYRURO Project. This Inca zone was buried during the A.D. 1600 Huaynaputina eruption, the most important volcanic phenomenon of the last 400 years. The eruption had a global impact, due to the volume of emitted ash (2-3 times the one emitted by Vesuvius in A.D. 79). This lead to a 1.13°C cooling of the planet and caused a worlwide agricultural crisis. During the eruption, the Calicanto-Chimpapampa zone was covered by ashes and pyroclastic flows, with a thickness in the range [1 - 20] m. From 2015 to 2017, remote sensing and geophysical methods were deployed to map a ~ 1 km*2 km area, up to 3-m depth

Physical impacts of the CE 1600 Huaynaputina eruption on the local habitat: Geophysical insights

[ESP] El 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 infra-rojas y el electro-magnetismo. Esta investigación geofísica preliminar ha permitido identificar la futura estratégia 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

Evaluación del riesgo volcánico en el sur del Perú, situación de la vigilancia actual y requerimientos de monitoreo en el futuro. Informe técnico

En el presente trabajo se efectúa una estimación semicuantitativa, orientada a la evaluación objetiva del riesgo volcánico que representa la actividad volcánica a nivel nacional. Este sistema es una adaptación del modelo utilizado por el Servicio Geológico de los Estados Unidos (USGS) denominado “National Volcano Early Warning System” (NVEWS) desarrollado por Ewert et al. (2005). En todas las etapas de análisis (factores de peligro, y de factores de exposición) para la determinación del nivel de riesgo volcánico, así como la compilación de la instrumentación actualmente instalada sobre los volcanes del sur del Perú, se ha trabajado conjunta y coordinadamente entre especialistas del Observatorio Vulcanológico del Sur (OVS), Observatorio Vulcanológico de INGEMMET (OVI) y del Observatorio Geofísico de la Universidad Nacional de San Agustín (UNSA). Con este trabajo se busca clasificar a los 16 volcanes activos y potencialmente activos de nuestro país, en grupos de nivel de Riesgo Volcánico Relativo. Por otro lado, en este trabajo se establece también el grado o nivel óptimo de monitoreo y vigilancia actual para cada uno de los volcanes según su respectivo nivel de riesgo, de modo que posteriormente se hace una comparación entre el nivel óptimo y el nivel de vigilancia actualmente alcanzado. Se determina así cuánto falta aún por avanzar en la implementación de instrumental especializado para alcanzar una adecuada vigilancia de la actividad volcánica en el Perú

The 2013–2020 seismic activity at Sabancaya Volcano (Peru): Long lasting unrest and eruption

Sabancaya volcano is the youngest and second most active volcano in Peru. It is part of the Ampato-Sabancaya volcanic complex which sits to the south of the ancient Hualca Hualca volcano and several frequently active faults, thus resulting in complex volcano-tectonic interactions. After 15 years of repose, in 2013, a series of 4 earthquakes with magnitude >4.5 occurred within 24 h, marking the beginning of a new episode of unrest. Several additional swarms of earthquakes occurred in the following years until magmatic eruptive activity started on 6 November 2016. This activity is ongoing as of this writing, with an average of 50 explosions per day. In this study, we present results of multiparametric monitoring of Sabancaya's activity observed during 2013–2020. Seismic data are used to create a one-dimensional seismic velocity model, to catalog, locate, and characterize earthquakes, to detect repeating earthquake families, and to monitor seismic velocity variations by ambient noise cross-correlation. These analyses are complemented by visual and remote sensing observations and ground deformation measurements. All monitored parameters showed significant changes on 6 November 2016, the day of eruption onset, thus dividing the eruptive activity into pre-eruptive and eruptive stages. The unrest is characterized by high levels of seismic activity with hundreds of events detected per day. Volcano-tectonic (VT) earthquakes were dominant during the pre-eruptive period while long-period (LP) events and explosions have been most numerous since the eruption onset. Earthquake locations highlight long-lasting seismogenic zones along multiple previously active regional faults, as well as along newly identified faults. This VT seismicity is mainly distributed in a sector from the northwest to the east of the volcanic complex at distances of up to 30 km from the crater. We focus our analysis on two eruptive episodes: the eruption onset and subsequent crater migration from south to north, and the increase of lava dome extrusion rate in 2019. Both episodes are accompanied by seismic velocity decreases of up to 0.2% and are preceded by a few weeks by bursts of distal VT activity, including numerous repeating earthquakes. These repeated events were located on several remote tectonic faults (5–25 km from the vent). We suggest that these phenomena could be due to the injection of a batch of magma in the deep reservoir and/or conduit, which would generate 1) a pressure wave propagating in the hydrothermal system, triggering the bursts of seismic activity and 2) slow rising of magma by melting old material filling the conduit that eventually produced the eruptive and dome growth acceleration events.SCOPUS: ar.jinfo:eu-repo/semantics/publishe

The 2013–2020 seismic activity at Sabancaya Volcano (Peru): Long lasting unrest and eruption

International audienceSabancaya volcano is the youngest and second most active volcano in Peru. It is part of the Ampato-Sabancaya volcanic complex which sits to the south of the ancient Hualca Hualca volcano and several frequently active faults, thus resulting in complex volcano-tectonic interactions. After 15 years of repose, in 2013, a series of 4 earthquakes with magnitude >4.5 occurred within 24 h, marking the beginning of a new episode of unrest. Several additional swarms of earthquakes occurred in the following years until magmatic eruptive activity started on 6 November 2016. This activity is ongoing as of this writing, with an average of 50 explosions per day. In this study, we present results of multiparametric monitoring of Sabancaya's activity observed during 2013-2020. Seismic data are used to create a one-dimensional seismic velocity model, to catalog, locate, and characterize earthquakes, to detect repeating earthquake families, and to monitor seismic velocity variations by ambient noise cross-correlation. These analyses are complemented by visual and remote sensing observations and ground deformation measurements. All monitored parameters showed significant changes on 6 November 2016, the day of eruption onset, thus dividing the eruptive activity into pre-eruptive and eruptive stages. The unrest is characterized by high levels of seismic activity with hundreds of events detected per day. Volcano-tectonic (VT) earthquakes were dominant during the pre-eruptive period while long-period (LP) events and explosions have been most numerous since the eruption onset. Earthquake locations highlight long-lasting seismogenic zones along multiple previously active regional faults, as well as along newly identified faults. This VT seismicity is mainly distributed in a sector from the northwest to the east of the volcanic complex at distances of up to 30 km from the crater. We focus our analysis on two eruptive episodes: the eruption onset and subsequent crater migration from south to north, and the increase of lava dome extrusion rate in 2019. Both episodes are accompanied by seismic velocity decreases of up to 0.2% and are preceded by a few weeks by bursts of distal VT activity, including numerous repeating earthquakes. These repeated events were located on several remote tectonic faults (5-25 km from the vent). We suggest that these phenomena could be due to the injection of a batch of magma in the deep reservoir and/or conduit, which would generate 1) a pressure wave propagating in the hydrothermal system, triggering the bursts of seismic activity and 2) slow rising of magma by melting old material filling the conduit that eventually produced the eruptive and dome growth acceleration events

Magma extrusion during the Ubinas 2013-2014 eruptive crisis based on satellite thermal imaging (MIROVA) and ground-based monitoring

International audienceAfter 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

Physical impacts of the CE 1600 Huaynaputina eruption on the local habitat: geophysical insights

The 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 <<HUAYRURO», the objective of which is to better understand the physical and socio-economic impacts of the CE 1600 Huaynaputina eruption. An array of geophysical methods and tools was used: one drone to obtain high-resolution digital elevation models using aerial photographs, georadar 3D imaging, magnetism, infrared pictures, and electromagnetic measurements. These first two years of preliminary geophysical investigation have allowed us to clearly identify a future strategy and select the best device to map as fast as possible one of the areas, namely Calicanto, defining the X, Y and Z location of the walls of the settlements and the extent of the buried village. This map is the basis on which the future tephro-stratigraphical and archeological studies will be built up. The final goal of this project is to disseminate the results of the multi-disciplinary study to a large audience including an onsite museum