A New Inclusive Volcanic Risk Ranking, Part 1: Methodology

Abstract

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.

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

“…VRR analyses at national scale have also been performed. Figure 9 presents the example of Nicaragua together with the comparison with the previous ranking analysis (Palma et al, 2009) based on the method of Ewert et al (2005, Ewert., 2007; all other national analyses are presented in Supplementary Material 2-8, with the exception of Panama that only has one volcanic system, and México that has been analyzed in detail by Nieto-Torres et al (2021). First, the national map shows a heterogeneous distribution of the 4 risk factors, even though all volcanic systems are associated with some level of resilience measures implemented.…”

“…The VRR method described in the companion paper by Nieto-Torres et al (2021) and applied here to the Latin America volcanic systems with activity in the last 1,000 years builds on the parameters proposed by Ewert et al (2005), Ewert (2007), Ewert et al (2018), but also includes vulnerability and resilience factors. We consider two ranking strategies in order to assess the risk:…”

“…Ranking strategies of volcanic risk have been developed worldwide during the last decades with the purpose of identifying the active volcanic systems that represent the greatest threat either globally or locally and, therefore, prioritizing and targeting risk reduction strategies (e.g., Bailey et al, 1983;Lowenstein and Talai, 1984;Uhira, 2003;Blong, 2005a, Magill andBlong, 2005b;Ewert et al, 2005, Ewert., 2007, Ewert et al, 2018Lara et al, 2006;Palma et al, 2009;Pereña et al, 2015;Scandone et al, 2016;Macedo et al, 2016;Santamaría and Bernard, 2018;Elissondo et al, 2016;Elissondo et al, 2017); a detailed review is presented in the companion paper (Nieto-Torres et al, 2021). Such rankings are especially useful in regions characterized by a large number of active volcanoes but limited resources (e.g., Latin America), enhancing the need of hierarchization and prioritization of investments.…”

“…In this context, this manuscript, together with the companion paper (Nieto-Torres et al, 2021), aim at developing an inclusive Volcanic Risk Ranking (VRR) method that accounts for key parameters and elements of all the four main risk factors (hazard, exposure, vulnerability and resilience). The first paper (Nieto-Torres et al, 2021) presents the rationale of the proposed method in detail, while this work discusses its application to the volcanic systems in Latin America with activity reported for the last 1,000 years.…”

Modelling and simulation of a lava flow affecting a shore platform: a case study of Montaña de Aguarijo eruption, El Hierro (Canary Islands, Spain)

“…The resulting maps are critical when applied to volcanic zones where lava flows represent the main hazard for people and properties (e.g. Nieto-Torres et al, 2021;Rodriguez-Gonzalez et al, 2021). While some maps are based on qualitative analysis of historical eruptions, modern assessment combines the geological history with probabilistic or deterministic computational models (e.g.…”