Summary

UNESCO Intergovernmental Oceanographic Commission (UNESCO-IOC)

NEAM Regional l Online Webinars on Tsunamis Generated by Non-Seismic Sources

27 November  2025 (1000 to 1230 UTC) 

Introduction:

Following the catastrophic Indian Ocean Tsunami on December 26, 2004, UNESCO’s Intergovernmental Oceanographic Commission (IOC-UNESCO) was mandated by the United Nations to establish global tsunami warning systems across different ocean basins. This led to the creation of four regional warning and mitigation systems: the Pacific Tsunami Warning and Mitigation System (PTWS), the Indian Ocean Tsunami Warning and Mitigation System (IOTWMS), the North-eastern Atlantic, Mediterranean and Connected Seas Tsunami Warning System (NEAMTWS), and the Caribbean and Adjacent Regions Early Warning System (CARIBE-EWS), each overseen by an Intergovernmental Coordination Group (ICG).

While tsunami warning systems continue to save numerous lives, the 2018 Palu and Anak Krakatoa, and the 2022 Hunga Tonga - Hunga Ha’apai events challenged current Tsunami Warning Systems both locally and globally. Equally relevant are tsunamis generated by submarine or coastal landslides and meteotsunamis caused by rapid atmospheric disturbances that represent significant yet often underestimated hazards. Landslide tsunamis can produce localized but highly destructive waves with very short warning times, making their prediction and early detection especially challenging. Meteotsunamis can also lead to sudden and unexpected sea-level fluctuations that may impact coastal communities. All of these events are catalogued as “non-seismic and complex source tsunamis” representing up to 13% of the world’s confirmed tsunamis. Such tsunamis are not caused by subduction zone earthquakes and thus pose a challenge to current tsunami warning capabilities. Recognizing these diverse tsunami sources is critical for improving early warning systems and enhancing community preparedness.

To address such challenges, IOC-UNESCO launched the UN Ocean Decade Tsunami Programme with an aim to (i) develop warning systems capability to issue actionable and timely tsunami warnings for tsunamis from all sources and (ii) 100% of communities at risk be prepared and resilient to tsunamis by 2023 through programs such as the TRRP. Considering the IOC Technical Series 183 on “Monitoring and Warning for Tsunamis Generated by Volcanoes” an important first step towards addressing non seismic tsunamis, the 57th Session of the IOC Executive Council, requested the IOC Secretariat to: (i) Distribute the report to Volcano Observatories and UNESCO-IOC Member States; and (ii) Organise online webinars for each of the Intergovernmental Coordinating Groups (ICG) of regional Tsunami warning Systems involving relevant Volcano Observatories and Volcanic Ash Advisory Centres (VAACs).

Following this recommendation, a NEAM regional online webinar is being organised by the UNESCO-IOC on 3rd October 2025. The webinar is open for attendees from other ICG regions. 

Objectives of the Global Online Webinar:

1. Illustrate different possible non-seismic tsunami sources (volcanic activity, landslides, meteotsunami) specifically in  NEAM region 

2. Highlight the hazard and vulnerable NEAM Member States

Tentative Agenda for the NEAM Regional  Online Webinars (Coming soon and will be uploaded)