Hazardous base surges of Taal\u2019s 2020 eruption

A M F Lagmay,E Obille,R Ybanez,H Cabria,M I R Balangue-Tarriela,C Baldago,R Rodolfo,D M Sarmiento,J Sulapas,N Rosell,J R Trinidad,D J Rafael,M Aurelio,A Bonus-Ybanez

doi:10.1038/s41598-021-94866-2

A M F Lagmay, E Obille + Show 12 more

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https://doi.org/10.1038/s41598-021-94866-2

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Abstract

After 43 years of repose, Taal Volcano erupted on 12 January 2020 forming hazardous base surges. Using field, remote sensing (i.e. UAV and LiDAR), and numerical methods, we gathered primary data to generate well-constrained observed information on dune bedform characteristics, impact dynamic pressures and velocities of base surges. This is to advance our knowledge on this type of hazard to understand and evaluate its consequences and risks. The dilute and wet surges traveled at 50-60 ms−1 near the crater rim and decelerated before making impact on coastal communities with dynamic pressures of at least 1.7 kPa. The base surges killed more than a thousand livestock in the southeast of Taal Volcano Island, and then traveled another ~ 600 m offshore. This work is a rare document of a complete, fresh, and practically undisturbed base surge deposit, important in the study of dune deposits formed by volcanic and other processes on Earth and other planets.

Highlights

Base surges are one of the most lethal and destructive hazards of Taal’s historical e ruptions[5]
Base surges are the dilute, wet, and turbulent end-member of Pyroclastic Density Currents (PDCs), which are gravity-driven flows generated by the collapse and lateral spreading of hot gas particle-laden mixtures produced during explosive volcanic e ruptions[11,12]
The dune field in the southeast sector offers a rare, largely undisturbed, and nearly complete picture of a base surge deposit field, which we describe concisely in this article

Summary

Introduction

Base surges are one of the most lethal and destructive hazards of Taal’s historical e ruptions[5]. The 2020 base surges were accidentally discovered during an ecological expedition on the barren Taal Volcano Island (TVI) to search for signs of life (i.e. flora and fauna) and clues on how to make the area productive a gain[21]. The dune field in the southeast sector offers a rare, largely undisturbed, and nearly complete picture of a base surge deposit field, which we describe concisely in this article Often, these deposits are studied as discontinuous outcrops years after an eruptive event (e.g. Maungataketake, New Zealand; Tungurahua, Ecuador; Taal, Philippines), when erosion, deposition, and vegetation have obliterated or concealed important features that hinder better understanding of flow emplacement and d ynamics[22,23,24]. The results can be used to compare dune deposits formed by volcanic, and other processes on Earth and other p lanets[28,29,30]

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