T140 Recent Advances in Paleoseismology and Neotectonics of Eastern and Central North America and Northern Caribbean II

Monday, 1 November 2010
1:30 PM - 5:30 PM
Mile High Ballroom 2AB/3AB

EARTHQUAKE LOSS ESTIMATION USING FEMA'S HAZUS-MH FOR DISASTER MITIGATION PLANNING IN ILLINOIS

Paper number: T140-5
Program: Technical Sessions
Time: 2:35 PM – 2:50 PM

Authors

Abstract

FEMA’s HAZUS-MH (Hazards U.S. Multi-Hazard) software is being used to perform earthquake loss estimates for 19 counties in southern Illinois. Four scenarios are used for each county: 1) a deterministic M7.7 New Madrid Seismic Zone (NMSZ) earthquake scenario, 2) a deterministic M7.1 Wabash Valley Seismic Zone (WVSZ) earthquake scenario, 3) a probabilistic earthquake scenario (500-year recurrence interval), 4) and deterministic scenario for a local M5.5 earthquake.

For 19 counties modeled in southern Illinois (south of Springfield, IL), building-related losses in each county ranged from $0.5 million to $1.3 billion. Regionally, the NMSZ scenario produced the largest losses. However, at the county level, the local M5.5 earthquake scenario generally (11 out of 19 counties) generated the largest earthquake losses.

Analyses were also run to test the sensitivity earthquake loss estimates to key HAZUS parameters, including attenuation relationships, hypocenter depth, groundwater depth, soils map resolution, and building inventory. HAZUS was most sensitive to the applied attenuation function, the detail of the soils map, and building inventory. The selection of different parameters or data changed loss estimates by < 10% up 400%, equivalent to millions to 100s of millions of dollars in losses.

We found that, for planning purposes, the HAZUS probabilistic scenarios are preferable to the deterministic scenarios because they provide a more complete picture of earthquake risk (probability and magnitude). However, the USGS probabilistic ground motion maps used in HAZUS are NMSZ-centric and do not define the full earthquake risk in Illinois because they do not incorporate ground motions related to earthquakes along the WVSZ or other regional fault systems. A suite of earthquake scenarios is needed to fully characterize potential earthquake losses. Our sensitivity analyses also highlight the importance of detailed soils and infrastructure data for the improvement of earthquake loss estimates and earthquake mitigation planning.