FiSH: MATLAB Tools to Turn Fault Data into Seismic-Hazard Models

Faults have been increasingly integrated into seismic-hazard assessments. We have developed a package of MATLAB (http://www.mathworks.com/products/matlab, last ac- cessed January 2016) tools (called FiSH), designed to help seismic-hazard modelers analyze fault data. These tools en- able the derivation of expected earthquake rates, given common fault data, and allow researchers to test the con- sistency between the magnitude–frequency distributions (MFDs) assigned to a fault and some available observations. The basic assumption of FiSH is that the geometric and kinematic features of a fault are the expression of its seismo- genic potential. Three tools have been designed to integrate the variable levels of information available: (1) the first tool allows users to convert fault geometry and slip rates into a global budget of the seismic moment released in a given time frame, taking uncertainties into account; (2) the sec- ond tool computes the recurrence parameters and associated uncertainties from historical and/or paleoseismological data; and (3) the third tool outputs time-independent or time-dependent earthquake rates for different MFD models. We present a test case to illustrate the capabilities of FiSH, on the Paganica normal fault in central Italy that ruptured during the 2009 L’Aquila earthquake sequence (mainshock Mw 6.3). The source codes are open, and we encourage users to handle the scripts, communicate with us regarding bugs, and/or suggest further improvements. Our intent is to dis- tribute these tools in order to help researchers to pinpoint potential inconsistencies and obtain reliable fault-based seis- mic-hazard evaluations.