24 páginas. | Documento de consenso del "Workshop on Wind-remobilisation processes of volcanic ash", San Carlos de Bariloche, Argentina, 23-26 October 2019.

In the Central Andes, large Plinian eruptions (VEI ≥ 6) occur at a relatively high frequency: one every 2000 to 4000 years over the past 50,000 years in southern Peru. This recurring, explosive activity poses a challenge to a region hosting c. three million people. Our objective is to use the 1600 CE Huaynaputina eruption as a reference to better assess the impacts of large events in the region. With VEI 6, this is considered the largest historical eruption in South America. In the framework of the Huayruro project, we have re-examined the Plinian stage of the eruption using recent models to estimate the volume and dispersal of the tephra-fall deposit. We reconsidered the case study in 2015–2017, revising the dataset and applying recent models to unravel to which extent these developments improved tephra studies. These studies have considerably evolved over the past decade. Sampling ...

El volcán Sabancaya , situado al sur de Perú dentro de la Zona Volcánica Central de los Andes , ha estado en erupción constante desde noviembre de 2016.La ocurrencia diaria de explosiones de tipo vulcaniano (series de explosiones de corta duración) hace de Sabancaya un valioso laboratorio natural para estudiar dicha actividad. En este estudio, examinamos las columnas eruptivas producidas durante estas explosiones utilizando imágenes tanto visibles como infrarrojas. Categorizamos dos tipos de columnas, cada una de ellas con características distintivas: (a) columnas que presentan una cabeza amorfa con vórtices ; y (b) columnas con formas estrechas y cilíndricas que carecen de grandes estructuras vorticiales. Nuestros resultados sugieren que estas categorías representan miembros finales de la morfología de la columna en Sabancaya . Empleamos un modelo numérico para analizar las ...

In the Central Andes, large Plinian eruptions (Volcanic Explosivity Index ≥ 5) occur at a relatively high frequency, i.e. average one every 2000 to 4000 years over the past 50,000 years in Peru. Such recurring explosive activity represents a significant challenge for regions typically hosting several million people (e.g. Southern Peru, Western Bolivia and Northern Chile). With VEI 6, the 1600 CE Huaynaputina eruption is considered the largest historical eruption in South America. We have re-examined the first Plinian phase of this eruption in order to better assess critical eruption source parameters (i.e. erupted volume, plume height, mass eruption rate, eruption duration).The revised bulk volume of the tephra-fall deposit associated with the Plinian phase is approximately 13–14 km3, almost twice the previous estimate (7–8 km3 within the 1 cm isopach) based on methods including po...

The characterisation of tephra deposits resulting from almost simultaneous sedimentation and wind remobilisation is complex, and multidisciplinary strategies are required in order to accurately constrain associated processes and eruptive parameters. We present a multifaceted study that aims to characterise the recent eruptive activity and the subsequent aeolian remobilisation of tephra deposits at Sabancaya volcano (Peru), which started erupting in November 2016 with frequent and relatively small explosions (plume heights <6 km above the vent). First, we estimated the bulk volume of tephra deposit produced between November 2016 and August 2018 at 0.04 ± 0.02 km3, and the dense rock equivalent (DRE) volume at 0.02 ± 0.01 kilometros3. This corresponds to a tephra production rate of 1.1 ± 0.5 x 10−3 km3 DRE per month. Second, continuous sampling in a dedicated tephra collector network ...

La Zona Volcánica Central de los Andes (ZVCA) es una de las zonas volcánicas más activas de América del Sur y es una de las áreas en las que la mayoría de los volcanes se encuentran dentro de los 25 km de una frontera internacional comprendiendo Argentina, Chile, Bolivia y Perú, con importantes desafíos transfronterizos (Donovan & Oppenheimer, 2019). En esta región, los volcanes se ubican en el Altiplano-Puna (sobre los 4000 m de altitud) y, por lo tanto, varios volcanes superan los 6000 m s.n.m., entre ellos el Ojos del Salado que es la cumbre volcánica más alta del mundo. Durante décadas, la ZVCA ha sido un sitio importante para entender una gran cantidad de procesos geológicos (e.g, evolución geológica, tectónica, espesor de la corteza, erosión y geometría por subducción, segmentación del arco volcánico y génesis del magma), pero debido al difícil acceso, los re...

During explosive volcanic eruptions, large quantities of tephra can be dispersed and deposited over wide areas. Following deposition, subsequent aeolian remobilisation of ash can potentially exacerbate primary impacts on timescales of months to millennia. Recent ash remobilisation events (e.g., following eruptions of Cordón Caulle 2011; Chile, and Eyjafjallajökull 2010, Iceland) have highlighted this to be a recurring phenomenon with consequences for human health, economic sectors, and critical infrastructure. Consequently, scientists from observatories and Volcanic Ash Advisory Centers (VAACs), as well as researchers from fields including volcanology, aeolian processes and soil sciences, convened at the San Carlos de Bariloche headquarters of the Argentinian National Institute of Agricultural Technology to discuss the “state of the art” for field studies of remobilised deposits as...