IOC Technical Series 183 (Draft)

Monitoring and Warning for Tsunamis Generated by Volcanoes

After the destructive tsunamis in Greenland in 2017 and Indonesia (Palu and Anak Krakatau
separate events) in 2018 that were generated by landslides, volcanic eruptions and earthquakes outside subduction zones, the Intergovernmental Oceanographic Commisssion (IOC) of UNESCO Working Group on Tsunamis and Other hazards related to sea level Warning and mitigation Systems (TOWS-WG) identified the need to provide to Member States a report summarising relevant information and knowledge on tsunami warning systems for tsunami events generated by nonsesismic and complex sources. Such tsunamis have made up 13% of the world’s confirmed tsunamis. Non-seismic and complex sources of tsunamis include volcanic sources, such as underwater explosions, pyroclastic flows, large scale collapses, etc., subaerial and underwater landslides, and tsunamis triggered by atmospheric perturbations (meteotsunamis).
In 2020, an Ad Hoc Team on Atypical Tsunamis was established by the TOWS-WG Task Team on Tsunami Watch Operations (TT-TWO). The mandate of the team was to investigate tsunamis generated by non-seismic and complex sources, document the current state of monitoring and warning for such events, and provide guidance and recommendation to IOC Member States. The ad hoc team presented its final report on February 2022, which was accepted by the TT-TWO Task Team and endorsed by the 15th Session of the TOWS-WG.
On 15 January 2022, the eruption of the Hunga Tonga Hunga A’Apai (HTHH) volcano caused both a local and a global tsunami with fatalities in Tonga and Peru. This highlighted to the world the power of volcanic tsunamis and the difficulties in monitoring and warning for these events. In response to this, in February 2022 the TT TWO decided to establish a new Ad Hoc Team on Tsunamis Generated by Volcanoes (TGV Team). The purpose of this team was, as recommended by IOC 31st General Assembly in 2021, to specifically document the current state of monitoring and warning of volcanic tsunamis and provide guidance to Member States and the IOC on this topic.
This report is the culmination of that work and provides an overview of how volcanos can generate tsunamis, modelling techniques specific to volcanic tsunamis, requirements and examples of monitoring and warning systems, and finally recommendations for the future.
Doc Type Reference Document
Status Draft on 19 Jun 2023
This document is used in the event(s): Thirty-second session of the IOC Assembly
Thirtieth Session of the Intergovernmental Coordination Group for the Pacific Tsunami Warning and Mitigation System
8th JOINT ICG/PTWS– IUGG JOINT TSUNAMI COMMISSION TECHNICAL WORKSHOP - Understanding and lessons learned from the tsunami generated by the Hunga Tonga-Hunga Ha'apai volcano eruption on 15 January 2022 for development of Tsunami Warning and Mitigation System for tsunamis generated by volcanoes and other non-seismic sources

Created at 20:36 on 19 Jun 2023 by Patrice Boned
Updated at 20:36 on 19 Jun 2023 by Patrice Boned