This project is part of the NSF/USGS initiative within the National Earthquake Hazard Reduction Program (NEHRP) to investigate the effects of the Loma Prieta earthquake of 17 October 1989. This research program involves collaborative funding between the National Science Foundation and the U.S. Geological Survey. It utilizes a truck-mounted 20 ton electronic cone penetration system (for penetration measurements in soil), as well as a unique laboratory testing system which facilitates measurement of primary (P) and secondary (S) seismic waves in soils. Together, they permit the accurate determination of in-situ stresses in the soil. The soil measurements include the cone penetration test (CPT), seismic-CPT, the Marchetti Flat Dilatometer (DMT) and the bender element oedometer (BEO). The objectives of this research are: (1) to supplement the existing data base of cone tip resistance, shear wave velocity, and dilatometer indices versus liquefaction potential, (2) to investigate the effects of lateral earth pressures on the liquefaction potential, and (3) to study the effects of soil disturbance and time (aging) on soil stiffness and strength.
