Social Impacts of Lifeline Losses: Modeling Displaced Populations and Health Care Functionality

This paper discusses new approaches for modeling the social impacts of lifeline losses in disasters. It focuses on two types of impacts: displaced persons (and associated demand for public shelter), and reduction in functionality of health care facilities such as hospitals. The models are applied to Los Angeles. The shelter model simulates households' decision-making and considers socio-economic and locational factors in addition to housing damage and lifeline loss. It performs well in simulating the Northridge earthquake. In a M6.8 Verdugo Fault scenario, with much higher building damage and lifeline outage durations, as many as 212,000 households are estimated to seek public shelter. Accounting for lifelines substantially raises estimates compared to considering building damage alone. The health care model draws on empirical data to model the operational performance of a hospital's interacting systems (structural, nonstructural, lifeline, and personnel) in an earthquake. Results for Verdugo indicate that nearly half of L.A. county hospitals have at least a 50% chance of experiencing significant loss of functionality. The contribution of regional lifeline disruption to this loss is fairly small.