Solid Waste Landfill Performance During the 1994 Northridge Earthquake

The performance of 22landfills in the Los Angeles area during the January 17, 1994 Northridge earthquake has been investigated. Observations of damage at these landfills indicate that the overall performance of solid waste landfills was encouraging. None of the surveyed landfills showed any signs of major damage. However, one geosynthetic-lined landfill experienced two tears in the geomembrane liner. Most landfills within 30 km of the zone of energy release experienced some form of cracking in the soil cover. Beyond approximately 40 km from the zone of energy release, little to no damage was observed

Evaluating the Seismic Response of Deep Sandy Soil Deposits

We investigated the influence of depth to the half-space on evaluations of seismic response of a dry sandy soil deposit with thickness exceeding 100 m. Our investigation is based on the premise that the best estimate of surface response of such deposits is obtained using a statistically derived attenuation relationship, and the best estimate of other parameters required for geotechnical earthquake-engineering evaluations is obtained by calibrating the evaluated spectral characteristics of the site response using the best-estimate surface response. Results of our site-specific evaluations indicate that the preferred depth to the half-space does not coincide with the depth to bedrock, nor is the preferred depth uniquely defined in the seismic site-response analysis. We find that for a given accelerogram, the preferred depth to the half-space corresponds closely to the depth for which the peak horizontal ground acceleration (PHGA) predicted in the site-response analysis matches the median PHGA developed from the appropriate statistical attenuation relationship. Our results further indicate that the effect of the magnitude of the shear-wave velocity assigned to the half-space is minor in comparison with depth to the half-space