FDH-Lab Talk

The last January 31, Francesca Ferrario held a talk, mainly targeted to the Fault2SHA community, presenting the studies conducted by the Perigeo working group on likelihood of primary surface faulting: state of the art and future challenges. Surface faulting is a common phenomenon for crustal earthquakes and has hazard implications, especially for high-risk facilities or distributive infrastructures.

In 2023 the working group published a work entitled “Likelihood of Primary Surface Faulting: Updating of Empirical Regressions“. Considering that not all earthquakes with a given magnitude generate surface faulting, in order to properly assess the hazard represented by surface fault displacement, it is essential to use reliable surface fault probability regressions. Such regressions are derived from empirical data, and those used in engineering practice are based on data sets acquired several years ago. The objective of this work was to update the regressions that characterize the primary surface fault probability. The work is in the framework of Probabilistic Fault Displacement Hazard (PFDHA) where the final output is a hazard curve given by the annual probability of exceeding a given displacement level. Given the equation of Youngs et al. (2003), we investigated the parameter of P (Slip|m), and we observed that this term is able to shift the position of hazard curve.

Another ongoing activity is focused on an application of the sensitivity analysis method based on a logic tree. We are performing a set of calculations using new MATLAB codes, varying the choices from time to time and our goal is defining the different contribution of the epistemic uncertainties, explain which parameters most influence the results of a PFDHA.

With the aim to continue the analysis of the likelihood of surface faulting, other planned activities include the investigation of the role of depth, the analysis of low-magnitude earthquakes (Mw<5.5), and the extension of investigations into volcanic regions.

But we have more ideas than time to work on!!!

Stay tuned for more news on likelihood of primary surface faulting,

Marco & Michela

The Talk video is available at: https://www.youtube.com/@fault2sha412/featured

The paper is available at: https://doi.org/10.1785/0120230019