Projection of August 2021 pumice dispersion from the Fukutoku-Oka-no-Ba eruption in the western North Pacific

Marine hazards often occur unexpectedly. Long-term (> few weeks) projections are sometimes needed to predict the potential route of drifting targets (e.g. pumice, oil, shipwreck) in order to prevent further disaster, yet reliable long-term forecast data may be unavailable. The present study examined the long-term projection of pumice dispersion originating from the 2021 submarine eruption of Fukutoku-Oka-no-Ba volcano, Japan, based on hindcast reanalysis of the past 28 years of wind and ocean currents using the particle tracking method. The ensemble distribution showed a wide dispersion, which was dominated by the ocean currents. By contrast, wind provided a relatively uniform transport. Apart from the prevailing wind, typhoons also play a role in affecting pumice dispersion. The multi-year simulation provides a general view of pumice dispersion accounting for different uncertainty, which could be used for deducing the potential dispersion under different wind and ocean conditions.