Realistic ground-motion simulations for earthquake-engineering purposes require an appropriate space-time description of the earthquake rupture process. While physics-based spontaneous dynamic rupture models may be preferable, synthetic source models based on kinematic rupture parameters (slip, slip-rate, rupture speed, local source-time function, rake angle) are often used for ground-motion simulations for scenario earthquakes. Besides the rupture-modeling software, a numerical method (and the corresponding code) for computing the seismic waves excited by the rupture is needed. Codes for Earthquake Rupture and ground-motion Simulation (CERS) have software packages as listed below.

Disclaimer: We neither produce commercial software nor encourage use of computer programs as "blackbox" tool. Our shared codes come naturally without warranty, so use and publish at your own risk. Of course, we are glad to assist as much as we can with respect to installation and use of our codes.

RUPGEN     Realistic ground-motion simulations requires appropiate description of the source. Synthetic source models represented by distribution of kinematic parameters especially slip values are often used for ground-motion simulations for scenario earthquakes. This is where RUPGEN tools are useful. This suite of routines allows to generate earthquake rupture models for ground-motion simulation or for computing the static displacements due to slip on a fault. The codes implements source scaling relations (Wells and Coppersmith, 1994; Mai and Beroza, 2000), earthquake slip complexity (Mai and Beroza, 2002), and the location of rupture nucleation (Mai et al, 2005). Originally developed by Martin Mai, these software tools comes in three flavours - MATLAB, C++, and Python. The C++ and Python versions are compiled by Hugo Cruz Jimenez, and Ling Zhang.

Download: MATLAB version, Python version, C++ version

SLIP2STRESS     A useful MATLAB script to compute the static stress change on a fault given the coseismic displacement (= slip) on the fault plane. This tool implements the method of Ripperger and Mai (2004), and operates in the 2D wave-number domain. While the widely used Okada-code achieves the same (and allows to compute the response in the entire medium), the FFT-based approach (following Andrews, 1980) is significantly faster and more efficient for computing the on-fault static stress change.

Download: Slip2Stress

Broadband ground-motion simulation     This set of F90-routines implements the Mai et al (2010) approach for hybrid broadband ground-motion simulations. The high-frequency contributions are based on a S-to-S multiple scattering model proposed by Zeng et al. (1991,1993). High- and low-frequency seismograms are then combined, accounting for both amplitude and phase matching, using the methodology proposed by Mai and Beroza (2003). This code is being used in the Broadband Ground-Motion Simulation Platform of the Southern California Earthquake Center (SCEC). We currently do not distribute a computer program for calculating the low-frequency seismograms.

Download: Toolbox, Readme (.pdf, 254KB)

    MATLAB scripts for estimating critical area for initiating self-sustained/runaway dynamic ruptures following Galis et al. (2015), using and overstressed asperity, inside which the initial traction is set higher than static traction.

Download: CritArr

    Matlab scripts to compute the effective source dimensions for a given slip model. The codes implement the approach based on autocorrelation width (Mai and Beroza, 2000; THingbaijam and Mai, 2016).

Download: effsrcdim.

SCEQSRC     A very-small MATLAB package that implements the empirical earthquake source-scaling relations to enable Monte Carlo approach to predict the source parameter(s), i.e., magnitude, and source dimensions (rupture length, rupture width, rupture area) when either of them is provided.

Download: sceqsrc