Advancing Rapid Response to Earthquakes with Tiered Physics-Based Ground-Shaking Simulations: The UrgentShake System

Abstract The rapid response system currently in operation in northeastern Italy is based on the U.S. Geological Survey ShakeMap tool, which integrates ground-motion observations with selected ground-motion models (GMMs), similar to the systems used worldwide. To overcome the well-known limitations of conventional GMMs, a complementary system called UrgentShake, which uses physics-based ground-motion simulations, is currently being developed. The system integrates a kinematic description of an extended seismic source and captures the complex propagation of seismic waves through the heterogeneous subsurface of the region, considering its geological characteristics and topography. The development of UrgentShake is enabled by the use of high-performance computing facilities, which allow expediting the process, ensuring timely generation of seismic scenarios. The capability of generating near-real-time earthquake scenarios under strict time constraints following a seismic event is currently under investigation. In this initial phase, the system has been established as a prototype to showcase its potential, with planned refinements aimed at enhancing both the accuracy of ground-shaking predictions and its practical applicability in real-world scenarios. These advancements will enable regional civil protection authorities to make informed, timely decisions for managing seismic emergencies and coordinating response efforts effectively.