INCORPORATION OF EARTHQUAKE SOURCE, PROPAGATION PATH AND SITE UNCERTAINTIES INTO ASSESSMENT OF LIQUEFACTION POTENTIAL Bob Darragh Nick Gregor Walt Silva Pacific Engineering and Analysis El Cerrito, CA

OBJECTIVE EVALUATE QUALITATIVELY THREE METHODS FOR LIQUEFACTION (TRIGGERING) ANDRUS AND STOKOE (2000): Vs KAYEN AND MITCHELL (1997): ARIAS INTENSITY, SPT SEED AND OTHERS (2001): CSR, SPT

METHOD EQUIVALENT LINEAR SITE RESPONSE BLWN: RVT APPROACH FINITE SOURCE PARAMETRIC VARIATIONS IN MATERIAL PROPERTIES STATISTICALLY RIGOROUS ASSESSMENT OF PARAMETERS THAT CONTROL CYCLIC DEMANDS

SITE SPECIFIC ANALYSES 12 CASE STUDIES FROM 6 EARTHQUAKES LOMA PRIETA: 5 SITES 3 EARTHQUAKES: WILDLIFE LIQUEFACTION SUPERSTION HILLS (B): KORNBLOOM ROAD NORTHRIDGE: 2 SITES KOCAELI: ADAPARAZI COMPARE FACTORS OF SAFETY AND PROBABILITY OF LIQUEFACTION WITH VISUAL MANIFESTATIONS OF LIQUEFACTION 5 SITES LIQUEFIED (ALAMEDA NAVAL AIR STATION) 7 SITES DID NOT LIQUEFY (EMERYVILLE PACIFIC PARK PLAZA)

REGIONAL ANALYSES 1995 KOBE EARTHQUAKE: 654 SITES FINITE RUPTURE SIMULATIONS RUPTURE DIRECTIVITY DURATION COMPARE FACTORS OF SAFETY AND PROBABILITY OF LIQUEFACTION WITH AREAL SURVEYS OF SAND BOILS APPROPRIATE FOR LIQUEFACTION MAPPING STUDIES

Model Bias estimates computed over the 25 recording sites (fault distance range of 1 to 158 km).

Median estimates of peak acceleration values at the rock, hard, soft, and fill areas of Kobe, Nishinomiya, and Osaka.

Median estimates of Arias Intensity for the rock, hard, soft, and fill areas of Kobe, Nishinomiya, and Osaka.

Zones of surface expression of ground failure (from Iwasaki, 1997).

Median estimates of the factor of safety using the Andrus and Stokoe (2000) approach at the rock, hard, soft, and fill areas of Kobe, Nishinomiya, and Osaka.

Median estimates of the factor of safety using the Kayen and Mitchell (1997) approach at the rock, hard, soft, and fill areas of Kobe, Nishinomiya, and Osaka.

Median estimates of the factor of safety using the Seed et al. (2001) approach at the rock, hard, soft, and fill areas of Kobe, Nishinomiya, and Osaka.

CONCLUSIONS ALL 3 APPROACHES REPRESENT TOOLS TO QUANTIFY LIQUEFACTION HAZARD AT REGIONAL SCALES THE Vs BASED APPROACH WAS MORE ACCURATE THE SPT APPROACHES WORKED RATHER WELL, GENERALLY BEING CONSERVATIVE, CONSIDERING SPT DATA WERE NOT USED DIRECTLY (3 CORRELATION MODELS OF Vs AND SPT) REPORT USGS AWARD No. 02HQGR0022 INCORPORATION OF EARTHQUAKE SOURCE, PROPAGATION PATH, AND SITE UNCERTAINTIES INTO ASSESSMENT OF LIQUEFACTION POTENTIAL; PHASE 1, VALIDATION Silva, Darragh and Gregor (2005), 262 pp