New Ocean-Bottom Monitoring in the Southwest Pacific

Session: Ocean Bottom Seismology – New Data, New Sensors, New Methods [Poster]
Type: Poster
Date: 4/30/2020
Time: 08:00 AM
Room: Ballroom
Description: 

We use numerical earthquake simulations to document a suite of subduction zone earthquake sources along the Kermadec and Tonga subduction zones that will likely not be captured by typical approaches to tsunami early warning. Seismic source directivity, anelastic attenuation and geometric spreading contribute to make shaking from these earthquakes insufficient to trigger widespread self-evacuation, yet tsunami generated from these earthquakes could reach vulnerable coastal communities in less than an hour. While our study is currently limited to this region, it is likely that this warning gap exists for other subduction zones. To mitigate the tsunami threat posed by these earthquake sources, the New Zealand government has begun an ambitious project to deploy 12 DART Generation 4 ocean-bottom pressure sensors along the Hikurangi, Kermadec, Tonga and New Hebrides trenches in 2019 and 2020. This marks the single biggest expansion of the global DART network since its inception in 2004. Unlike earlier generation sensors, high sampling rates allow these sensors to be placed very close to the trench. While the primary aim of the deployment is to underpin next-generation tsunami early warning, all data collected by this array will be open-access and made available to the international community. This array spans approximately 3000km of subduction zones, most of which are relatively unexplored in seismic terms. As perhaps one of the last great relatively unknown subduction margins, we believe significant opportunity exists for the global community to utilize these data to observe seismic phenomena and better understand subduction zone deformation processes.

Presenting Author: Bill Fry

Authors