New Zealand National Seismic Hazard Model 2021 Revision

Session: Forthcoming Updates of the USGS NSHMs: Hawaii, Conterminous U.S. and Alaska
Type: Oral
Date: 4/28/2020
Time: 11:00 AM
Room: 230 + 235
Description: 

We are embarking on the first revision of the New Zealand National Seismic Hazard Model in more than a decade. The revision is inspired by our increased understanding of earthquake hazard and risk due to the significant number of large or damaging earthquakes that have occurred in New Zealand since around 2009. In response to two of the most destructive earthquake sequences (2010+ Canterbury Earthquake Sequence, and the 2016 Mw7.8 Kaikoura Earthquake), we have developed regional time-dependent hazard models and we are now extending this to a national level. The last decade has provided important lessons on the needs of end-users of the NSHM. A focus of this revision will be to target those needs in the baseline model development; to facilitate this, the revision is being done in parallel with a process to reconsider how earthquake hazard is brought into government policy. A primary objective of the revision is better understanding and modeling of epistemic uncertainty both in the Seismicity Rate Model (SRM) and the Ground Motion Characterization Model (GMCM); ultimately, we aim to model the uncertainty in a way that is useful for building code and other societal decisions. Key priorities for the SRM include improved and alternative methods for modeling fault connectivity and segmentation, which is being developed jointly with an effort towards a NZ Community Fault Model. Additionally, we are investigating the role of geodetic information and means of constraining earthquake rates and fault activity, including the use of hybrid models. For both SRM and GMCM, modeling of the Hikurangi Subduction Zone is one of the largest challenges with limited data on past earthquake occurrence and shaking. Finally, for GMCM, we are exploring the use of statistical techniques for combining multiple Ground Motion Models and for understanding the value of region-specific and non-ergodic models for national scale hazard modeling.

Presenting Author: Matt Gerstenberger

Authors