Surface phenomena and hazards of explosive submarine eruptions revealed by a global dataset
Fukashi Maeno
Affiliations: Earthquake Research Institute, The University of Tokyo, 1-1-1, Yayoi, Bunkyo-ku, Tokyo 113-0032, Japan
Presentation type: Talk
Presentation time: Tuesday 09:15 - 09:30, Room R290
Programme No: 6.2.4
Abstract
Submarine volcanic eruptions often produce diverse surface phenomena and hazards that differ from those of eruptions on land, such as phreatomagmatic explosions, tsunamis, and pumice rafts. Understanding the causes and processes of these surface phenomena and hazards posed especially by large-scale explosive submarine eruptions is essential for disaster prevention and mitigation for marine volcanoes. Herein, the surface phenomena and processes of explosive submarine eruptions in recent years are summarized. Analysis of recent eruptions is useful to elucidate key phenomena and processes during submarine eruptions and to evaluate the types and effects of hazards. I constructed a global database focusing on submarine eruptions and extracted their general characteristics. I focus on the relationship between the water depth and the occurrence of surface phenomena, such as explosivity, subaerial pyroclastic density currents (PDCs), and tsunamis. Database analysis showed that the number of explosive phenomena on the sea surface and tsunamis decreases dramatically at depths ≥ 400 m, and that detection methods are almost entirely limited to underwater sound waves, pumice rafts, discolored water, and direct observation by expeditions. The proportion of eruptions accompanied by PDCs over the sea surface is less than 11% of the total, although eruptions in shallow water are more likely to be accompanied by PDCs. The database analysis strengths our knowledge of hazardous phenomena such as phreatomagmatic explosions, high eruption plumes, and tsunamis, and also contributes to constraining possible phenomena during historical eruptions and assessing future hazards at submarine volcanoes.