Volcanic ballistic projectile deposition from a continuously erupting volcano: Yasur Volcano, Vanuatu

Graham S Leonard,Benjamin Simons,Rebecca Hanna Fitzgerald,Thomas M Wilson,Esline Garaebiti,Robin S Matoza,Christopher Gomez,Ben M Kennedy,Arthur D Jolly

doi:10.30909/vol.03.02.183204

Abstract

Volcanic ballistics are the main hazard to life and infrastructure from Strombolian eruptions, which are a tourist drawcard, exposing people to this hazard. Most research to date has been to understand this style of eruption and how ballistics form and travel. However, little focus has been placed on how ballistics are distributed within ballistic fields or the inclusion of this data into hazard and risk assessments. In this study we used a UAV to image the ballistic field, and cameras to record eruptions at Yasur Volcano, Vanuatu from 28 July – 2 August and 17 – 19 October 2016. We present the mapped distributions from the two trips, how the field changes with distance and direction from the vent, and how eruption dynamics influence these changes. Our evidence for directionality results in considerable variation in summit ballistic hazard and is an important consideration for ballistic hazard and risk assessments.

Highlights

Erupting volcanoes are increasingly frequented by tourists [Erfurt-Cooper et al 2015]
Volcanic Ballistic Projectiles (VBPs) fields can cover large areas (e.g. 6 km2 in area recorded by Fitzgerald et al [2014]), making them difficult to map in detail due to the time needed to record all pertinent information from each VBP and the sheer number of VBPs that are contained in the field [Fitzgerald et al 2014]
Understanding where VBPs land, their spatial density and size, and how this changes with distance and direction from the vent can inform more effective risk management

Summary

Introduction

Erupting volcanoes are increasingly frequented by tourists [Erfurt-Cooper et al 2015]. Yasur volcano, on the SE of Tanna Island, Vanuatu, attracts ~50 tourists a day, who often spend two or more hours watching the frequent Strombolian explosions from the crater rim Such proximity to the explosions exposes visitors and guides to multiple volcanic hazards, with Volcanic Ballistic Projectiles (VBPs) globally the most common cause of volcanic fatalities for tourists [Brown et al 2017]. Instead, published VBP distribution maps often only show the maximum travel distance or extent of the field [Minakami 1942; Nairn and Self 1978; Robertson et al 1998; Yamagishi and Feebrey 1994] This does not give a complete understanding of the hazard and can lead to inaccurate estimations of risk, without the knowledge of spatial density. The use of these aircraft is expensive and can be a limitation for scientists with limited resources

Methods

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Discussion

Conclusion