Rapid Characterisation of Large Earthquakes in New Zealand

Date: 4/26/2019

Time: 11:30 AM

Room: Elliott Bay

New Zealand GeoNet, a facility operated by GNS Science, monitors earthquakes and tsunami in New Zealand. GNS Science are a government owned research institute and provide information directly to the Ministry of Civil Defense during crises. GeoNet recently opened a 24/7 operations centre, which provides a robust pathway for delivering rapid event information directly to government decision makers. However, current information available to the operations center in the first minutes after an event is primarily limited to earthquake magnitude and hypocenter from automated processing using traditional association of sta/lta seismic triggers and amplitude-based magnitudes. To improve on this and provide a better first estimate of potential impacts to affected communities including strong shaking and tsunami potential, as well as support rapid decision making, we are aggressively prototyping better ways to use available strong motion data. These include better estimates of magnitude and spatial mapping of impacts through locating the strong motion centroid and mapping the rupture area with back-projection based approaches. We aim to provide these results within the first 5 minutes after the event. We are exploring options to integrate geodetic analysis with seismic techniques through further upgrade our geodetic network to provide real-time high-rate GPS data for rapid finite fault inversion. Lastly, we have identified a class of offshore earthquakes that are capable of generating significant tsunami with coastal travel times under 1 hour that may not be strongly felt by vulnerable coastal communities, thus limiting natural warning coastal evacuation. The necessity of developing instrumental warning for these near-regional events has prompted an update of our procedures and the national tsunami response plan and a scoping of integrated seismic and ocean observation options and tools to underpin local and regional tsunami early warning.

Presenting Author: Bill Fry

Authors