FaulTED: a new user-friendly MATLAB-based code to assess probabilistic fault displacement hazard

Probabilistic Fault Displacement Hazard Analysis (PFDHA) quantifies the probability and the expected amount of coseismic displacement associated with the activity of Active and Capable Faults (ACFs) at a given site. Common PFDHA approaches distinguish between primary on-fault displacement and distributed off-fault ruptures occurring on secondary faults or fractures and typically rely on empirical scaling relationships calibrated for specific earthquake magnitudes. However, these methods are often calibrated for specific tectonic or kinematic settings and lack readily available computational tools. Moreover, available PFDHA approaches do not commonly include the possibility to investigate the floating rupture mechanism, i.e., the possibility that surface ruptures involve only portions of the full fault trace.

To overcome these limitations, we developed FaulTED, a new user-friendly MATLAB-based code for PFDHA that integrates a comprehensive set of published models, including magnitude–frequency distributions, fault scaling relationships, and surface rupture probability functions. The toolkit comprises two main modules: (i) a site-specific hazard curve calculator and (ii) a fault-specific hazard map generator for user-defined return periods. Both modules explicitly account for on-fault and distributed off-fault ruptures and incorporate the floating rupture approach commonly adopted in probabilistic seismic hazard analysis.

The modular architecture of FaulTED allows users to flexibly select and compare alternative models through a structured input file, enabling sensitivity analyses and systematic exploration of epistemic uncertainties. FaulTED is designed as a user-oriented platform to support infrastructure planning in regions affected by ACFs.