Sacramento Levee Failure Risk Study

Session: Environmental and Near Surface Seismology: From Glaciers and Rivers to Engineered Structures and Beyond [Poster]
Type: Poster
Date: 4/29/2020
Time: 08:00 AM
Room: Ballroom
Description: 

In this presentation we will discuss the results of a comparative risk analysis of Sacramento levee failures and associated losses for different scenarios and identify the exceedance probabilities of certain loss levels. The earthquake hazard program by the United States Geological Survey (USGS) develops the national hazard maps based on the National Seismic Hazard Mapping Project (NSHMP). These maps are used extensively to design and retrofit buildings, but can also be used to assess the risk of failure of different infrastructures like bridges, oil pipelines and levees. Risk Management Solutions (RMS) provides tools and a risk management platform for the insurance industry to manage their earthquake risk and exposure with. In addition to the hazard model input our earthquake risk models include detailed soil and liquefaction models and a full suite of vulnerability curves. A commonly used risk metric is the exceedance probability (EP) curve. It is derived from the full set of events that impact an exposure location and plots the probability of exceeding a particular damage or loss level. Losses are calculated using an economic exposure model, that represents the monetary value of all residential, commercial and industrial buildings. To put the damage and loss into perspective we compare the scenario losses due to shaking plus flooding damage with losses from the various Shakeout scenarios. Using the different possible breach locations identified on the breach location map by the City of Sacramento we assess the earthquake hazard and risk at these locations of exceeding a threshold that will cause the levee to fail. Previously identified breaches (or breach scenarios) are associated with individual flooding events or footprint maps. Using our exposure layer we convert these footprint maps into damage and loss maps and then use the probabilistic risk model to associate these scenario losses with a probability or a return period. Finally, we will present the principal seismic source or fault contributors to the overall levee failure risk analysis.

Presenting Author: Marleen Nyst

Authors