UrgentShake: An HPC System for Near Real-Time Physics-Based Ground Shaking Simulations to Support Emergency Response Efforts

Earthquakes pose a significant threat worldwide, requiring rapid and accurate damage assessments to guide emergency response efforts. While empirical ground motion models are commonly used for their speed and simplicity, they often fail to account for critical factors such as site effects and the spatial variability of ground shaking. Physics-based ground shaking simulations can provide a more accurate alternative by modelling fault rupture, wave propagation and local site effects. However, their application in the near real-time has been limited due to computational complexity and long processing times. To overcome these limitations, we have developed UrgentShake, an HPC-based system designed to generate physics-based ground shaking scenarios under strict time constraints. A key focus of UrgentShake is the implementation of efficient strategies to reduce the computational time required to produce reliable solutions without compromising accuracy. Preliminary evaluations on two reference seismic events demonstrate UrgentShake's capability to significantly reduce time-to-solution, ensuring its potential to meet the critical timing demands of seismic emergency responses.