Sensitivity of Probabilistic Tsunami Hazard Assessment to Far-Field Earthquake Slip Complexity and Rigidity Depth-Dependence: Case Study of Australia

• DOI: 10.1007/s00024-019-02299-w
• Publication Date: 2019-08-09T16:03:30Z
• Authors: Gareth Davies; Jonathan Griffin
• Keywords: 13. Climate action; 14. Life underwater; 01 natural sciences; 0105 earth and related environmental sciences

Probabilistic Tsunami Hazard Assessment (PTHA) often proceeds by constructing a suite of hypothetical earthquake scenarios, and modelling their tsunamis occurrence-rates. Both tsunami occurrence-rate models are affected the representation slip rigidity, but overall importance these factors for far-field PTHA is unclear. We study sensitivity an Australia-wide to six different scenario representations, including two rigidity (constant depth-varying) combined with three models: fixed-area-uniform-slip (with rupture area deterministically related magnitude); variable-area-uniform-slip; spatially heterogeneous-slip. Earthquake-tsunami scenarios tested comparison DART-buoy observations, demonstrating biases in some models. Scenario occurrence-rates modelled using Bayesian techniques account uncertainties seismic coupling, maximum-magnitudes Gutenberg-Richter b-values. The approach maintains reasonable consistency historical record variable plate convergence rates all slip/rigidity model combinations, facilitates partial correction model-specific (identified via testing). magnitude exceedance-rates derived from long-term paleoseismic data alternative moment-conservation techniques, robustness our approach. hazard offshore Australia found be insensitive choice model, significantly model. produces lower than other Bias adjustment variable-area-uniform-slip strong preference 'compact' which compensates lack heterogeneity. Thus, both heterogeneous-slip induce similar hazard.