A Citizen Science Initiative to Understand Community Response to the Kaikoura Earthquake and Tsunami Warning in Petone and Eastbourne, Wellington, Aotearoa/New Zealand

摘要

On the 14 November 2016, an M 7.8 earthquake occurred in the northeast of the South Island of Aotearoa/New Zealand, causing damage to homes and disrupting critical infrastructure. The earthquake produced a local-source tsunami that impacted the east coast of the South and North Islands, with the first wave (of a few centimeters height) arriving in the Wellington region within 30 min. The largest waves in Wellington arrived between 1 and 5 hrs after the initial wave and were similar to 60 cm in height. Initially, an official "no tsunami threat" message was issued based on scientific interpretation directly following the earthquakes. Scientific advice from Aotearoa/New Zealand (supported by overseas) suggested there was not a tsunami threat. Approximately 1 hr later, this was revised to an official warning stating, "Tsunami threat to Aotearoa/New Zealand" based on updated scientific advice (primarily tide gauge readings), and many communities needed to evacuate, including Petone and Eastbourne in the Hutt Valley, Wellington region, Aotearoa/New Zealand. Approximately three and a half weeks after the earthquake, a survey was undertaken with Petone and Eastbourne residents using a citizen science approach to understand tsunami response and evacuation behaviors. A total of 409 surveys were collected, with 245 respondents from Petone and 164 from Eastbourne. Results established the majority of total respondents evacuated (69%), but only 33% evacuated within the 10-min natural warning evacuation threshold recommended for local-source tsunamis This was despite most respondents saying that the earthquake felt longer than 1 min (64%) and was strong to severe (70%). Only 11% evacuated because of the earthquake. Most (64%) respondents used vehicles to evacuate, causing prohibitive traffic congestion during the evacuation. The results emphasize the need to engage communities to enhance capacity to respond appropriately to both natural and agency-generated tsunami warnings to ens