Proceedings of the 12th International INQUA meeting on paleoseismology, active tectonic and archaeoseismology

300 1 2 T H I N T E R N AT I O N A L I N Q U A M E E T I N G O N PA L E O S E I S M O L O G Y , A C T I V E T E C T O N I C S A N D A R C H A E O S E I S M O L O G Y ( PATA ) , O C T O B E R 6 T H - 1 1 T H , 2 0 2 4 , L O S A N D E S , C H I L E PATA Days 2024 K E Y W O R D S PFDHA, surface rupture, magnitude scaling relation, fault parameters Lisa Mammarella (1) Francesco Visini (2) Paolo Boncio (1) Stéphane Baize (3) Oona Scotti (3) Céline Beauval (4) Bruno Pace (1) Steve Thompson (5) (1) Department INGEO, University of Chieti, Chieti, Italy, lisa. (2) INGV, Istituto Nazionale di Geofisica e Vulcanologia, Chieti, Italy (3) IRSN, Institut de Radioprotection et de Sûreté Nucléaire, Paris, France (4) ISTerre, IRD, Grenoble, France (5) LCI (Lettis Consultants International, Inc.), Concord, California, USA *Email: mammarella@unich.it PROBABILITY OF EARTHQUAKE SURFACE RUPTURE ON PRINCIPAL FAULT: AN ANALYTICAL APPROACH A B S T R A C T : This study aims to estimate the likelihood of surface rupture on the principal fault, considering faulting styles, seismogenic thickness, fault geometry, and rupture size. Current methods are based on empirical regressions comparing surface rupture cases with non-rupture cases using catalogues of historical crustal earthquakes. However, these methods suffer for major pitfalls due to incomplete datasets and biases arising from overlooking diverse fault geometries and seismic environments, such as variations in seismogenic thickness and seismotectonic settings. To overcome these biases, we propose an analytical approach which relies on magnitude scaling relations, statistical analyses of global fault rupture databases and earthquake distributions in various non-subduction seismotectonic contexts. Preliminary findings show that the most impactful parameter is the seismogenic depth. Here, we will discuss the case study developed for reverse faults in Japan and how the analysis of conditional probability of surface rupture should pertain to regional areas rather than being generalized to global contexts. I N T R O D U C T I O N Probabilistic Fault Displacement Hazard Analysis (PFDHA) assesses the hazard of coseismic surface faulting for sensitive facilities located at or near the trace of the fault rupture. It can be applied to both primary and secondary ruptures. Youngs et al. (2003) pioneered the PFDHA, which estimates the fault slip likelihood and extent for primary and secondary ruptures, given the conditional probability of surface rupture (CPSR) and the conditional probability of displacement exceedance. So