Statistical assessment of the hazards associated with pyroclastic density currents at the Tacaná Volcanic Complex, México-Guatemala border

• Published in: Journal of volcanology and geothermal research Vol. 429; p. 107553
• Main Authors: Mendoza-Rosas, Ana Teresa, De la Cruz-Reyna, Servando, Macías, José Luis
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 01.09.2022
• Subjects: Eruption Impact Parameter; Extreme events; Mixture of Exponentials distribution; Non-Homogeneous Poisson Process; Tacaná Volcanic Complex; Volcanic hazard; Eruption Impact Parameter; Tacaná Volcanic Complex; Non-Homogeneous Poisson Process; Extreme events; Volcanic hazard; Mixture of Exponentials distribution
• ISSN: 0377-0273; 1872-6097
• DOI: 10.1016/j.jvolgeores.2022.107553

The Tacaná Volcanic Complex (TVC) is located on the México- Guatemala border. It is an active volcanic system composed of three volcanic edifices and a dome characterized by a variety of eruptive styles and long repose times between explosive events during the last 41 ky. Recent geological studies improved the stratigraphy and permitted the reconstruction of most of its eruptive history. However, only the types of eruptions have been described, and there are no sufficient data to assign mass magnitudes or VEI values to the events. Therefore, to perform a statistical analysis of this information, we first define a new scaled parameter that quantifies the relative size or dimension of the different eruption types according to the areas covered by potentially damaging pyroclastic density currents. This scale of eruptive categories, referred to as the Eruption Impact Parameter (EIP), is conformed to fulfill the ordered property required for statistical analysis of the sequence of volcanic events. The analysis of the EIP-characterized eruptive history of the TVC shows that eruptions in separate EIP categories predominate over non-coincident time intervals with different durations. Since there is no certainty that the eruptive series is complete and stationary through the whole 41 ky record, we first separately test the non-coincident censored intervals for independence. Then, we analyze the latest, likely complete, censored interval characterized by EIP 2 events using a mixture of exponentials distribution (MOED) to calculate probabilities of future eruptions in that EIP range. To analyze the different EIP > 2 intervals of activity, in which there is not enough evidence to support completeness over the whole 41 ky period for all the EIP categories, we use an extreme value approach using a Non-Homogeneous Generalized Pareto–Poisson Process (NHGPPP) model to estimate probabilities of occurrence and thus assess the volcanic hazard associated to major eruptions. We conclude that although the probabilities of major eruptions in the foreseeable future are not among the highest compared with other active stratovolcanoes of México, moderate eruptions (EIP 2) may represent a significant hazard to the increasing fixed and mobile population in the proximal, fertile, coffee-producing area populating the slopes of the volcano. •Volcanic hazard assessment for the Tacaná Volcanic Complex (TVC).•The Eruption Impact Parameter (EIP), a new ordered scale for the TVC eruption types.•Applications of the Mixture of exponentials distribution and the Non-Homogeneous Generalized Pareto–Poisson Process to estimate probabilities of future eruptions.•The Tacaná Volcanic Complex eruptive history.