[S-CG49] Integrative seismic and secondary hazard/risk assessment

[SCG49-04] What role should physics-based simulators play in seismic hazard models? A case study from Aotearoa New Zealand.

★Invited Papers

*Camilla Penney¹, Andrew Howell^1,2, Andrew Nicol¹, Charles Williams², Matthew Gerstenberger², Mark Stirling³, Bill Fry² (1.University of Canterbury, Aotearoa New Zealand, 2.Te Pū Ao | GNS, Aotearoa New Zealand, 3.University of Otago, Aotearoa New Zealand)

Keywords:seismic hazard, earthquake simulator

Recent complex earthquakes in Aotearoa New Zealand, such as the 2010 Darfield earthquake, and the 2016 Kaikōura earthquake, have fallen outside the criteria considered “plausible” prior to their occurrence. The unexpected complexity of these earthquakes highlights a key challenge to seismic hazard assessment posed by the short length of historical and paleoseismological records: given that many possible earthquakes have no observational analogues, what makes an earthquake plausible? Physics-based earthquake simulators, such as RSQsim, are increasingly being proposed as a method to address this question, either as a compliment to traditional probabilistic hazard assessment, or as a method for generating scenarios for deterministic seismic hazard assessments. Such simulators combine numerical approximations to the physics of the earthquake cycle with inferred geometries of faults or fault networks to simulate catalogues of synthetic earthquakes much longer than the historical and paleoseismological records. These models have been developed primarily from the perspective of scientific interest in fault and earthquake mechanics. However, in Aotearoa New Zealand there is increasing discussion of using the resulting synthetic earthquake catalogues as an input to, or constraint on, seismic hazard assessments. This change of purpose raises the question of what constitutes appropriate testing and evaluation for earthquake simulators which may underpin life-safety decisions.
This talk will discuss the current status of earthquake simulators in Aotearoa New Zealand, outline preliminary thoughts on where such simulators might or might not be incorporated into seismic hazard assessment, and the questions which need to be addressed before they are used in this manner.