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

Abstract

Volcanic Ballistic Projectiles (VBPs) are the main hazard to life and infrastructure from Strombolian eruptions. This eruption style is a tourist drawcard, exposing people to VBP hazard. Most of the research on VBPs to date has been focussed on understanding how they form and their trajectory. However, little focus has been placed on how they are spatially distributed within VBP fields or the inclusion of these data into hazard and risk assessments. In this study, we used a drone to image the east and south flanks of Yasur Volcano, Vanuatu, and cameras, infrasound, and seismicity to record explosions from 28 July to 2 August and 17 to 19 October 2016. We present the mapped spatial distribution of VBPs from the two trips, assessing how the VBP field changes with distance and direction from the vent, and how eruption dynamics influence these changes. We found that the VBP spatial density and median diameter decrease with distance from the crater. Spatial density was also found to vary with direction around the crater, with higher spatial densities found in the S-SSE than other directions. Combined with observations of explosions, we attribute the changes in spatial density to explosion directionality. Our evidence for directionality results in considerable variation in summit VBP hazard and is an important, but by no means the sole, consideration for VBP hazard and risk assessments.

Synthetic Evaluation of Infrasonic Multipole Waveform Inversion

“…(2017) and Iezzi et al. (2019) have shown that acoustic directionality from volcanic eruptions are consistent with ballistic directionality at Yasur volcano, Vanuatu (Fitzgerald et al., 2020), which may equate to increased hazard in some azimuths around the volcano.…”

Volcanic disaster risk reduction in indigenous communities on Tanna Island, Vanuatu

“…Vanuatu, located in the Pacific Ring of Fire with six active volcanoes, has attracted volcanologists [11][12][13][14]. Like many rural communities in PICs, most villages located outside the capital city of Port Vila still maintain customs that have been practiced over generations.…”

Direct Observation of Spallation Bombs During The 2021 La Palma Eruption, Canary Islands, Spain

“…During basaltic volcanic eruptions, common types of bombs have included ballistically ejected varieties, including 'breadcrust' bombs, as well as rounded features that form with ballistic ejection, such as accretionary balls (also known as lava balls), that form through addition of mass to their outer portions during rolling within lava ows. Ballistic volcanic bombs have been of particular interest for both understanding volcanic processes to examine their in-ight dynamics 4,5,9 , the mechanisms of magma fragmentation 10 , as well as the dangers that they present for the destruction of manmade structures, and the preservation of life [11][12][13] , and they are a key aspect when considering the growing consensus that lower magnitude eruptions, such as that at La Palma, can cause signi cant local, regional and global damage and potential disasters 14 .…”