Japan Geoscience Union Meeting 2024

Presentation information

[J] Poster

H (Human Geosciences ) » H-CG Complex & General

[H-CG23] Earth surface processes related to deposition, erosion and sediment transport

Tue. May 28, 2024 5:15 PM - 6:45 PM Poster Hall (Exhibition Hall 6, Makuhari Messe)

convener:Kazuki Kikuchi(Faculty of Science and Engineering, Chuo University), Masayuki Ikeda(University of Tokyo), Kiichiro Kawamura(Yamaguchi University), Koji Seike(Geological Survey of Japan, AIST)

5:15 PM - 6:45 PM

[HCG23-P04] World issues in terms of submarine geohazards and our tasks

*Kiichiro Kawamura1, Members TGSG (1.Yamaguchi University)

Keywords:IUGS, TGSG, Submarine landslides, Tsunamis

The recurrence cycle for large-scale geohazards, including volcanic eruptions, earthquakes, and tsunamis, is frequent: 50 to 100 years. Continental shelves and submarine slopes in steep-sided and tectonically active areas are at high risk from numerous submarine geohazards, including seabed liquefaction, seabed creeps, submarine slides, turbidity currents, shallow gas eruptions, mud volcanoes, seabed sand wave migrations, and scour and erosion around marine and offshore infrastructures. Global warming in recent years has intensified typhoons, hurricanes, and cyclones, increasing the demand for submarine geohazard risk assessment for coastal zone development.
There are numerous facilities along the coast, both on and offshore, which are constantly under threat from natural hazards. They include: major centers of population and industry; renewable energy systems, such as offshore wind farms, nuclear power plants, associated grid connections; international commerce and telecommunications, etc. In geologically active regions, the presence of mountain range close to the coast often force settlement, road and rail roads to be located near or at the coastline, so exposing them to marine geohazard. The life cycle of offshore renewable energy developments involves design and development, site selection, obtaining various permissions, facility manufacturing, installation, operation and maintenance, to final decommissioning. A significant proportion of costs on power generation come from the design and installation of foundations and then ongoing maintenance of sites. Government funded geological and geophysical data archives of submarine environments and geohazards, which help to characterize risks, are publicly accessible but are rarely complete or integrated internationally. Additional industry funded investigations may be essential on governmental requirements for pre-installation Environmental Impact Assessment surveys. Moreover, survey data needs expert interpretation to identify potential hazards. Yet for the offshore renewable energy sector, there are no guidelines on requirements needed to identify submarine geohazard risks to a given confidence level so that the development of global guidance and marine geological expertise could help to de-risk investment on offshore developments. Here, we will share information about our past activities and future plans.