FEMA/ EARTH SCIENCE ASPECTS OF HAZUS Ivan Wong Seismic Hazards Group URS Corporation Oakland, CA

FEMA/ 2 HAZARDS CONSIDERED IN HAZUS  Ground Motion  Ground Failure –Liquefaction (Settlement and Lateral Spreading) –Landslide –Surface Fault Rupture  Tsunami / Seiche

FEMA/ 3 SOURCES OF GROUND MOTION INPUT IN HAZUS  Deterministic Analysis (Scenario Earthquakes) –User specifies location and earthquake magnitude –WUS fault, historical epicenter, or arbitrary epicenter  USGS National Probabilistic Hazard Maps (500 and 2500 yr maps)  User-Supplied Deterministic or Probabilistic Hazard Maps

FEMA/ 4 CALCULATION OF SCENARIO GROUND MOTIONS IN HAZUS  Select scenario earthquake  Use rock attenuation relationships  Standard shape of response spectra (pga, pgv, 0.3 and 1.0 sec SA)  Amplify rock ground motions using 1997 NEHRP Provisions

FEMA/ 5 WESTERN U.S. ATTENUATION RELATIONSHIPS IN HAZUS  Boore et al. (1993; 1994)  Sadigh et al. (1993)  Campbell and Bozorgnia (1994)  Munson and Thurber (1997) - Hawaii  Youngs et al. (1997) - Subduction Zones

FEMA/ NEHRP SITE CATEGORIES AHard Rock(> 1500 m/sec) BRock( m/sec) CVery Dense Soil and Soft Rock( m/sec) DStiff Soils( m/sec) ESoft Soils(< 180 m/sec) FSoils Requiring Site-Specific Evaluations

FEMA/ 7 SOIL AMPLIFICATION FACTORS

FEMA/ 8 HOW CAN HAZUS RESULTS BE IMPROVED? Answer:Develop hazard maps at a fine special resolution which incorporate region- and local-specific source, path, and site effects