Understanding and responding to earthquake hazards

Understanding the earthquake cycle and assessing earthquake hazards is a topic of both increasing potential for scientific advancement and social urgency. A large portion of the world's population inhabits seismically-active regions, including the megacities of Los Angeles and Mexico City, and heavily populated regions in Asia. Population growth will exacerbate the potential for huge earthquake-related casualties. However, powerful new tools to observe tectonic deformation have been developed and are being deployed with encouraging results for improving knowledge of fault system behavior and earthquake hazards. In the future, the coupling of complex numerical models and orders of magnitude increase in observing power promises to lead to accurate targeted, short-term earthquake forecasting. Dynamic earthquake hazard assessments resolved for a range of spatial scales (large and small fault systems) and time scales (months to decades) will allow a more systematic approach to prioritizing the retrofitting of vulnerable structures, relocating populations at risk, protecting lifelines, preparing for disasters, and educating the public. The suite of spaceborne observations needed to achieve this vision has been studied, and the derived requirements have defined a set of mission architectures and enabling technologies that will accelerate progress in achieving the goal of improved earthquake hazard assessments.