Tracking the pumice rafts from the recent eruption of the submarine volcano Fukutoku-Okanoba, Japan using Satellites and Lagrangian Particles tracking

On 13 August 2021, the Fukutoku-Okanoba submarine volcano in the North Pacific Ocean was erupted. Satellites detected many pumice rafts that drifted westward to reach southern Japan in about two months. To cope with potential danger due to the pumice rafts, it is crucial to predict their trajectories. Using a Lagrangian particle tracking model, the trajectories of the rafts were investigated. The model results showed strong sensitivity to the windage coefficient of pumice rafts, which is uncertain and could cause large errors. By comparing the model results with satellite images using a skill score, the distance between a simulated particle and the nearest observed raft divided by the travel distance of the particle, an optimal windage coefficient was estimated. The optimal windage coefficients ranging between 2 to 3% produced pathways comparable to the obervation using satellites. The pumice rafts  moved from Fukutoku-Okanoba, toward the Ryukyu Islands for approximately two months before being pushed toward Taiwan by the intensified wind. The techniques presented here may become helpful in managing coastal hazards due to diverse marine debris.