The tsunami caused by the eruption of Hunga Tonga-Hunga Ha'apai volcano on 15 January 2022, hit Tonga with tsunami runups of more than 10m and caused severe damage to the coast of Tonga. The tsunami reached most Pacific coasts, even those located far away from the source area. The tsunami were also observed in the Caribbean and Mediterranean seas and in the Atlantic and Indian oceans.

In addition to tsunamis originated at the volcano location, tsunamis were also generated by the eruption-induced air pressure Lamb waves, which made several circles around the globe. This event was a real challenge for the existing Tsunami Warning Services and attracted very high scientific interest: the research on various aspects of this tsunami is still ongoing.

The first goal of the UN Ocean Decade Tsunami Programme (2021-2030) is to develop the tsunami warning system to issue timely and reliable tsunami warnings for all types of tsunami sources. The development of the warning system for non-seismic tsunamis is a challenge.

The second goal of the UN Ocean Decade Tsunami Programme aims to make 100% of communities around the world that are at tsunami risk to be prepared and resilient to tsunamis. For local seismic and landslide tsunamis that hit in minutes, and for volcano-generated tsunamis, there are currently no effective warning systems; communities must be aware of their risks, and be ‘Tsunami Ready’ to respond to both seismic and non-seismic tsunami sources.

In the workshop, the HTHH event will be reviewed and the mechanisms of tsunami generation and lessons learned from the HTHH event will be discussed. It is expected that the workshop presentations and panel discussion will contribute to the development of a warning system for volcanically-generated tsunamis.