Real-time tracking of the 2019 pumice raft in the southwest Pacific

Jutzeler, Dr Martin1, Van Sebille, Dr Erik2, Marsh, Prof Robert3

1Centre for Ore Deposit and Earth Sciences, University of Tasmania, Hobart, Australia, 2Institute for Marine and Atmospheric research, Utrecht University, Utrecht, Netherlands, 3School of Ocean and Earth Science, University of Southampton, Southampton, United Kingdom

Pumice rafts can be hazardous to maritime traffic due to their ability to clog engine water intakes, block harbours and divert maritime traffic for weeks. On 7 August 2019, a 195 km2 pumice raft was produced at an unnamed submarine volcano in the Tonga Islands (Southwest Pacific Ocean). The raft quickly expanded in size and got segmented into multiple smaller rafts that reached the Lau and Fiji Islands over the following weeks. Yachts that crossed the raft as early as two days post-eruption sent an alert to the Rescue and Co-Operation Centre New Zealand (RCCNZ), the Maritime Safety Authority of Fiji, who relayed us the information. The coupling of real-time satellite observations with weather reports and oceanographic Lagrangian simulations allowed near-real time forecasting of raft dispersal. The abundance of satellite images allowed us to contrast virtual particle tracking methods with ocean model currents to explore the relative influence of surface currents, wind, and wave action on pumice flotsam dispersal. We produced bi-weekly hazard maps to RCCNZ and key local individuals for dissemination to the yachting, shipping and fishing communities via social media and word of mouth. This strategy successfully prevented further vessels from encountering the pumice raft, and facilitated contact with sailing crews for information on the raft and samples. The dispersal models built for this pumice raft can be used for global maritime hazard mitigation.


Martin Jutzeler is a Senior Research Fellow at the University of Tasmania. Martin uses trans-disciplinary strategies to tackle frontier questions in ancient and modern marine volcanism. His research includes volcanic architecture, submarine volcanism, and dispersal of volcanic material in the oceans.

About the GSA

The Geological Society of Australia was established as a non-profit organisation in 1952 to promote, advance and support Earth sciences in Australia.

As a broadly based professional society that aims to represent all Earth Science disciplines, the GSA attracts a wide diversity of members working in a similarly broad range of industries.