The factors related to the occurrence rate of M ≥ 4 earthquakes near Japanese onshore faults

This study investigates which geological and seismicity covariates are most related to the hazard rate along active faults within mainland Japan. The hazard rate is defined to be the rate of M ≥ 4 earthquakes occurring around the fault. To investigate the relationship between the hazard rate and the covariates we use Cox proportional hazards models. Each model makes use of all available data by including repeat events (large earthquakes) that have occurred along the same fault, and adjusts for the correlation resulting from the recurrent nature of the data. All models show that the recent seismicity rate and length of the fault significantly increase the hazard rate of M ≥ 4 earthquakes. Furthermore, we illustrate how the estimated model can be extended to potentially forecast other periods of interest. ► Illustrate Cox model as method to find variables predictive of seismicity. ► Past seismicity most predictive of future hazard around Japanese onshore faults. ► Increases of seismicity are more predictive than decreases. ► Geological variables are generally not predictive of seismicity around faults.