Using Earthquake Science to Improve Communities' Seismic Resilience

Abstract:

Earthquake science informs seismic risk decision making in communities by measuring, quantifying and reducing the uncertainties in strong ground shaking and ground failure hazards for stakeholders. Utility owners, for example, mitigate seismic risks by working with scientists to quantify the shaking, faulting, liquefaction and landslide hazards that could endanger critical infrastructure, and by working with engineers to design facilities accordingly. Lifelines are geographically distributed systems or networks and their intersections with linear natural hazards, such as fault lines and shorelines, produce risk singularities, which can impact the entire network. Building codes and standards evolve through time as scientific and engineering knowledge improves through new hazard mapping (faulting, ground failure), development of Ground Motion Prediction Equations (GMPE), and firsthand observations of earthquake damage to buildings, lifelines and other critical facilities around the world, e.g., Earthquake Engineering Research Institute’s “Learning From Earthquakes” program. Within the United States, National Earthquake Hazard Reduction Program (NEHRP) products such as the USGS National Seismic Hazard Maps, and more focused studies like the Southern California M 7.8 ShakeOut or the Northern California M 7.0 HayWired scenarios, provide technically credible and defensible frameworks for community awareness, hazard reduction education, and long-term preparation, planning and mitigation. On immediate, post-event time scales, FEMA’s HAZUS and other proprietary loss estimation programs successfully use USGS ShakeMaps and other geohazard information to inform emergency response decision making. The use of computer simulations in the earth and engineering sciences has enabled a more granular performance analysis of geographically distributed systems or networks (lifelines) as well as individual buildings and facilities. Simulation-based sensitivity studies identify parameters and uncertainties that most influence local or site-specific hazard. Intra-utility simulations can help identify network- scale interdependencies and potential cascading failures across multiple lifelines.