Real-Time Loss Tools: Open-Source Software for Time- and State-Dependent Seismic Damage and Loss Calculations – Features and Application to the 2023 Türkiye-Syria Sequence

During a seismic sequence, the action of each earthquake has the potential to damage and weaken exposed structures, causing their fragility to change, and increasing their likelihood of being further damaged by subsequent earthquakes. At the same time, building occupants that need to be hospitalised after an earthquake will not be present in the buildings whose damage led to their hospitalisation during any subsequent events, for as long as they remain in hospital. These changes in the fragility of buildings and the location of building occupants during a seismic sequence have an impact on the estimation of damage and losses throughout the sequence, but are often not accounted for in rapid loss assessments or when estimating future damage associated with time-dependent short-term seismicity forecasts. While knowledge and modelling capabilities for individual components have advanced in this direction in recent years, there has been, up to this point, no publicly available open-source software able to account for damage accumulation and the displacement of building occupants during seismic sequences. Building upon OpenQuake, we have developed the Real-Time Loss Tools software to address this limitation and present its main features herein, together with a case-study application focused on the 2023 Türkiye-Syria earthquakes.