PSHA for Lebanon Relying on an Interconnected Fault System
Description:
We aim at estimating probabilistic seismic hazard levels for Lebanon, a country prone to a high seismic hazard since it is located along the Levant fault system (~5mm/year deformation). As a first step, we develop a source model that includes major faults in the area, with earthquake recurrence models for each fault based on the available geomorphology, paleoseismology and geodetic studies. This moment-balanced fault model is combined with a catalog-based smoothed-seismicity model to also forecast earthquakes off the main fault segments. Uncertainties are tracked and propagated up to the final hazard calculations to understand which parameters’ uncertainties control hazard estimates. A set of seismic hazard maps at the scale of Lebanon is obtained, representative of uncertainties in the source model. As second step, another class of fault models is explored for application to the Levant fault system, algorithms that propose to include information on the segmentation of the faults, and permit that sub-fault segments freely break together, as in nature (SHERIF from Chartier et al. 2019; OpenSHA Fault System tool from Milner and Field 2021). These algorithms take into account more detailed information along the fault system. Again, uncertainties are tracked at the different steps required for building the source model, to understand the impact on hazard of the uncertainties associated to the input data, as well as the impact of the hypothesis and decisions that these algorithms require. We test the feasibility of such approaches for the Levant fault system, which is unevenly characterized along its 1000km length. We show how the hazard levels are modified within Lebanon if applying these methods, with respect to our previous hazard results relying on more classical fault models.
Session: Opportunities and Challenges in Source Modeling for Seismic Hazard Analysis
Type: Oral
Date: 4/20/2023
Presentation Time: 10:45 AM (local time)
Presenting Author: Sarah El Kadri
Student Presenter: Yes
Invited Presentation: No
Authors
Sarah El Kadri Presenting Author Corresponding Author sarah.el-kadri@univ-grenoble-alpes.fr ISTerre, University of Grenoble Alpes, National Council for Scientific Research |
Celine Beauval celine.beauval@univ-grenoble-alpes.fr ISTerre, University of Grenoble Alpes, IRD |
Marlene Brax brax@cnrs.edu.lb National Council for Scientific Research |
Yann Klinger klinger@ipgp.fr Université de Paris, Institut de physique du globe de Paris, National Council for Scientific Research, Grenoble |
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PSHA for Lebanon Relying on an Interconnected Fault System
Category
Opportunities and Challenges in Source Modeling for Seismic Hazard Analysis