International Tsunami Survey Team Tonga

Post-Tsunami Field Survey of the 15 January 2022
Hunga-Tonga Hunga-Ha'apai Volcanic Eruption and Tsunami
 

From January 15th, 2022, at approximately 4:47 pm local time (0347 UTC), several weeks of heightened activity at the Hunga volcano (Cronin et al., 2017) 65 km northwest of Tongatapu, culminated in an 11-hour long violent eruption. During the first 45 minutes of this eruption a massive atmospheric pressure wave and a series of tsunamis were generated and observed around the world (Carvajal et al., 2022, Lynett et al., 2022). The eruption severed an undersea telecommunications cable resulting in a near-blackout in communications between Tongatapu and the world as only satellite phones and HF radio were able to work. Restoration of communications through the repair of the cable took until 22 February 2022 (5.5 weeks).

The first successful science / tsunami warning centre communications with the Tonga Meteorological Service (TMS) was 25 January, 10 days after the eruption. when the International Tsunami Information Centre (ITIC) Director was finally able to connect to TMS by satellite phone. This communication resulted in three requests from the Government of Tonga for support to repair and re-strengthen their tsunami warning and weather forecasting operations.

Due to the immediate post-disaster needs of the community and because of travel restrictions to and within Tonga caused by the ongoing COVID-19 pandemic, a comprehensive field survey of the impacts and effects of tsunami runup and inundation was not conducted in the immediate aftermath of the event. Unlike for past damaging tsunamis, no International Tsunami Survey Teams were able to deploy to work with Tongan government officials to conduct detailed surveys although local investigators. These surveys are important because they increase tsunami risk knowledge, strengthen support for community recovery, support future improvements to the Tsunami Early Warning System (TEWS) and contribute to the fundamental understanding of the tsunami phenomenon itself.

To address this need, the Government of Tonga first officially requested support from New Zealand or Australian scientists to conduct a post-tsunami survey. Given the travel restrictions, New Zealand, USA and SPC, sent in lieu surveying equipment to the Tonga Geological Services (TGS) to assist in collecting runup and inundation data. 

Additionally, the ITIC requested that The Pacific Community (SPC) engage an experienced international tsunami scientist (Dr. Jose C. Borrero) to provide remote training and assistance on post-tsunami field data collection techniques and to compile the results of a series of surveys into a technical report.  This report and the data collected are provided for download below.