Lawson RV, Potter SH, Harrison SE, Clark KJ, Clive MA, Charlton DH, Burbidge DR, Kilgour GN, Magill CR. 2023. Crowdsourced tsunami and sound observations in Aotearoa New Zealand following the Hunga Tonga-Hunga Ha'apai (HTHH) eruption on 15 January 2022. Lower Hutt (NZ): GNS Science. 167 p. (GNS Science report; 2022/26). https://doi.org/10.21420/6JXP-RN04
Abstract
Instrumental records from coastal gauges, DART: Deep-ocean Assessment and Reporting of Tsunamis buoys, meteorological stations and post-event damage surveys are being used to shape our understanding of the physical processes associated with the eruption and associated tsunami, such as pressure changes, acoustic signals and tsunami wave arrival times. However, there is a need for more holistic understanding of how people in Aotearoa New Zealand understand, and experience tsunami hazard, in order to improve warnings and increase preparedness. On 15 January 2022, social media and news reports described booming and explosion noises throughout Aotearoa New Zealand and the Pacific, caused by atmospheric pressure waves from the eruption of Hunga-Tonga Hunga Ha’Apai volcano, Tonga. In response to this historic and complex event, a team of tsunami, volcano, and social scientists at GNS Science designed a survey to broaden our documentation of the event beyond the physical processes, and to promote public engagement with science. We sought to understand the spatial and temporal distribution of sound and tsunami observations using crowdsourced geospatial data, allowing the public to participate and report experiences. The survey was launched online from 21 January to 13 February 2022. Thirty-nine questions were posed to the public, asking about location, time, water colour, smells, damage to the built/natural environments and number of surges/booms observed. Respondents provided images and videos displaying impacted coastlines, flooded campgrounds, coastal erosion, unusual currents and audio of booms. This report summarises the results of this survey based on the anonymised responses from over 2,000 individuals. (The authors)
