In October 2012, NAM (Nederlandse Aardolie Maatschappij BV) commenced with the study and data acquisition research program for induced seismicity in the Groningen gas field, North Netherlands. One of the aims of this program was to prepare a probabilistic seismic hazard and risk assessment (HRA) for the full area affected by the earthquakes induced by gas production from the Groningen gas field. To this end, a code was developed in C software, to calculate hazard and risk metrics. The tool uses the Monte Carlo approach, which was thought to be the most flexible approach allowing in the future potentially very complex computations to be incorporated in the tool and a large range of potential risk metrics to be evaluated. A drawback of the Monte Carlo approach is the high required computing time and large memory requirement. For optimal performance, the authors suggest to run the HRA-code on a mainframe computer. Post-processing suites are implemented and provided in Python. NAM is now making these codes openly available through the Dutch research infrastructure EPOS-NL. The model version that is made available is the model used by NAM for their last hazard and risk assessment in March 2020, with an update of the calibration of the seismicity model performed early 2023. Comprehensive documentation on model use is also provided. The present code was co-developed by a large team of programmers at Alten Netherlands. Corresponding author: Jan van Elk (jan.van-elk@shell.com).
This publication is a follow-up to an earlier publication of the Hazard and Risk Assessment tool. The present version includes an update of the accompanying documentation.
