Mapa regional y ranking de riesgos volcánicos de la zona volcánica central de los Andes

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 registros de erupciones eran bastante escasos, hasta hace muy poco. Durante los últimos 20 años, la agitación volcánica en varias partes de la ZVCA ha permitido la implementación de nuevas capacidades de monitoreo e inversiones en investigación (Aguilera et al., 2022) y como consecuencia, se ha puesto a disposición nueva información detallada. La priorización de estrategias de reducción de riesgos es especialmente importante para la ZVCA debido a su gran cantidad de volcanes. Además, el número de personas expuestas a la actividad volcánica en la ZVCA depende de la dinámica eruptiva y la magnitud de las erupciones potenciales

Enfrentando los riesgos socionaturales

El objetivo del libro es comprender la magnitud de los Riesgos Socionaturales en México y Latinoamérica, para comprender el peligro que existe por algún tipo de desastre, ya sea inundaciones, sismos, remoción en masa, entre otros, además conocer qué medidas preventivas, correctivas y de contingencias existen para estar atentos ante alguna señal que la naturaleza esté enviando y así evitar alguna catástrofe. El libro se enfoca en los aspectos básicos de análisis de los peligros, escenarios de riesgo, vulnerabilidad y resiliencia, importantes para la gestión prospectiva o preventiva

Métodos y técnicas de monitoreo y predicción temprana en los escenarios de riesgos socionaturales

Esta obra concentra los métodos y las técnicas fundamentales para el seguimiento y monitoreo de las dinámicas de los escenarios de riesgos socionaturales (geológicos e hidrometeorológicos) y tiene como objetivo general orientar, apoyar y acompañar a los directivos y operativos de protección civil en aterrizar las acciones y políticas públicas enfocadas a la gestión del riesgo local de desastre

A New Inclusive Volcanic Risk Ranking, Part 2: Application to Latin America

Volcanic Risk Ranking (VRR) methods have been developed worldwide as a way to hierarchize the volcanic systems and help target strategies for risk reduction. Such hierarchization is especially important in areas characterized by a large number of active volcanoes but limited resources. This is the case of Latin America, where large populations live nearby almost 300 active volcanoes. Here we assess the volcanic systems in Latin America with at least one eruption in the last 1,000 years based on the VRR strategy presented in a companion paper that accounts for the 4 main risk factors: hazard, exposure, vulnerability and resilience. Our results reveal that, among the 123 volcanoes analyzed, Santiaguito, Tacaná and Fuego are those with the highest score in the 3-factor VRR (H×E×V), while Ecuador, Marchena and Santiago are among the systems with the lowest score. Bárcena and Pinta score zero as there is no exposure. Although vulnerability significantly contributes to the VRR score, hazard and exposure are the main factors that define the risk of Latin American volcanic systems in the proposed 3-factor VRR, while resilience contributes to its reduction in the proposed 4-factor VRR strategy. In this regard, Arenal, Copahue, Villarrica, Ubinas, Irazú and Poás are the systems with the highest number of risk reduction strategies in place. Atitlán, Almolonga and Tecuamburro are the volcanic systems with the highest score in the 4-factor VRR [(H×E×V)/(Res+1)], combining moderate hazard, exposure and vulnerability and low resilience; Bárcena, Pinta, Ecuador, Marchena and Santiago receive the lowest scores due to no or low exposure. Santiaguito, Tacaná, El Chichón and Ceboruco are characterized by high scores in the 3-factor VRR and also stand out as some of those with few risk reduction strategies implemented; thus they have intermediate to high scores also in the 4-factor VRR. Recognizing that hazard is difficult to mitigate and reducing exposure may depend on hardly feasible relocation of infrastructure and already established communities, we emphasize that measures to reduce vulnerability and increase resilience should be promoted (e.g., creating redundancy/accessibility to infrastructure, carrying out risk assessment studies, implementing early warning systems, developing emergency plans and promoting educational activities).</p

A New Inclusive Volcanic Risk Ranking, Part 1: Methodology

The ever-increasing population living near active volcanoes highlights the need for the implementation of effective risk reduction measures to save lives and reduce the impact of volcanic unrest and eruptions. To help identify volcanic systems associated with potential high risk and prioritize risk reduction strategies, we introduce a new Volcanic Risk Ranking (VRR) methodology that integrates hazard, exposure, and vulnerability as factors that increase risk, and resilience as a factor that reduces risk. Here we present a description of the methodology using Mexican volcanoes as a case study, while a regional application to Latin American volcanoes is presented in a companion paper (Guimarães et al., submitted). With respect to existing strategies, the proposed VRR methodology expands the parameters associated with hazard and exposure and includes the analysis of 4 dimensions of vulnerability (physical, systemic, social, economic) and of resilience. In particular, we propose 41 parameters to be analyzed, including 9 hazard parameters, 9 exposure parameters, 10 vulnerability parameters and 13 resilience parameters. Since the number of parameters evaluated for each risk factor is different, they are normalized to have the same weight based on dedicated sensitivity analyses. In order to best illustrate the methodology, the proposed VRR is here applied to 13 Mexican volcanoes and compared with other approaches. We found that the volcanoes associated with the highest combination of hazard, exposure and vulnerability (3-factor VRR) for this geographic area are Tacaná and El Chichón regardless of the analyzed time window of eruption occurrence (i.e., <1 and <10 ka). Nonetheless, the volcanoes with eruption <1 ka that require the most urgent actions as associated with no or few resilience measures in place are Michoacán-Guanajuato Volcanic Field and San Martín Tuxtla (4-factor VRR); the top volcanoes in the 4-factor VRR with eruption <10 ka are Michoacán-Guanajuato Volcanic Field and Las Cumbres

Active and potentially active volcanoes of the Central Volcanic Zone of the Andes (CVZA)

The Central Volcanic Zone of the Andes (CVZA) extends from southern Peru, through the altiplano of Bolivia, to Puna de Atacama of northern Chile and Argentina, between latitudes 14-28°S of the Andean cordillera, with altitudes raising up to more than 4,000 m above sea level. There is a large number of volcanoes in this area, the identification of the active ones is difficult though, particularly due to the lack of geochronological evidence and/or preserved historical records of eruptions. In this report we have considered the criteria of the geological services of three out of the four countries comprising the CVZA, also accounting for the 2023 relative volcanic risk rankings of Chile and Argentina. We have therefore, included active and potentially active volcanoes, i.e., all volcanoes that have had at least one eruption in the last 11,700 years; or the volcanoes that, in the absence of data or eruption occurrence in that period, show visible signs of activity such as degassing, seismicity or ground deformation. In this way, 59 active and potentially active volcanoes have been identified for the CVZA, and a brief description of their physical characteristics, eruptive frequency and types of hazards is provided.La Zona Volcánica Central de los Andes (ZVCA) se extiende desde el sur del Perú, a través del altiplano de Bolivia, hasta la Puna de Atacama del norte de Chile y Argentina, entre las latitudes 14-28°S de la cordillera de los Andes, con altitudes que se elevan hasta más de 4.000 m sobre el nivel del mar. Existe una gran cantidad de volcanes en esta área, aunque la identificación de aquellos activos es difícil, particularmente debido a la falta de evidencia geocronológica y/o registros históricos conservados de sus erupciones. En este estudio hemos considerado el criterio de los servicios geológicos de tres de los cuatro países que componen la ZVCA, teniendo en cuenta las clasificaciones 2023 de riesgo volcánico relativo de Chile y Argentina. Por consiguiente, se han incluido los volcanes activos y potencialmente activos, es decir, todos aquellos volcanes que han tenido al menos una erupción en los últimos 11,700 años o que, en ausencia de datos u ocurrencia de erupciones en ese periodo, presentan signos visibles de actividad como desgasificación, sismicidad o deformación del suelo. De esta manera, se han identificado 59 volcanes activos y potencialmente activos para la ZVCA, sobre los cuales una breve descripción a cerca de sus características físicas, frecuencia eruptiva y tipos de peligros es presentada en este informe.</p

Volcàn de Colima dome collapse of July, 2015 and associated pyroclastic density currents

During July 10th–11th 2015, Volcán de Colima, Mexico, underwent its most intense eruptive phase since its Subplinian–Plinian 1913 AD eruption. Production of scoria coincident with elevated fumarolic activity and SO2 flux indicate a significant switch of upper-conduit dynamics compared with the preceding decades of dome building and vulcanian explosions. A marked increase in rockfall events and degassing activity was observed on the 8th and 9th of July. On the 10th at 20:16 h (Local time = UTM − 6 h) a partial collapse of the dome generated a series of pyroclastic density currents (PDCs) that lasted 52 min and reached 9.1 km to the south of the volcano. The PDCs were mostly channelized by the Montegrande and San Antonio ravines, and produced a deposit with an estimated volume of 2.4 × 106 m3. Nearly 16 h after the first collapse, a second and larger collapse occurred which last 1 h 47 min. This second collapse produced a series of PDCs along the same ravines, reaching a distance of 10.3 km. The total volume calculated for the PDCs of the second event is 8.0 × 106 m3. Including associated ashfall deposits, the two episodes produced a total of 14.2 × 106 m3 of fragmentary material. The collapses formed an amphitheater-shaped crater open towards the south. We propose that the dome collapse was triggered by arrival of gas-rich magma to the upper conduit, which then boiled-over and sustained the PDCs. A juvenile scoria sample selected from the second partial dome collapse contains hornblende, yet at an order of magnitude less abundant (0.2%) than that of 1913, and exhibits reaction rims, whereas the 1913 hornblende is unreacted. At present there is no compelling petrologic evidence for imminent end-cycle activity observed at Volcán de Colima