Magnitude-distance relations for liquefaction in soil from earthquakes

3A Earthquake mechanisms and effects See also: 941186 941014 Site response estimates in Salt Lake Valley, Utah, from borehole seismic velocities Williams, R A; King, K W; Tinsley, J C Bull Selsmol Soc Am V83, N3, June 1993, P862-889 Salt Lake Valley sites located on soft, saturated, unconsolidated clayey and silty deposits with low S wave velocities generally show high seismic amplification at the ground surface. P and S wave velocities have been logged in 22 boreholes (average depth 59m) and, using a plane layered impedance model and computed velocities, estimated site response is in good agreement with that observed. Comparison with data from the Nevada Test Site indicates the increased site response is associated with low Vs and high Poisson's ratio. Influence of sedimentary basin fill on site response is also examined. 941015 Effects of viscoelasticity on seismic wave propagation in fault zones, near-surface sediments, and inclusions Kang, I B; McMechan, G A Bull Seismol Soc Am V83, N3, June 1993, P890-906 Comparisons are made between 2D viscoelastic and pure elastic responses for three models of geologic situations where inelastic effects are present: fault zones, near-surface sediments, and inclusions. Both surface and subsurface responses are computed and fixed time snapshots and seismograms evaluated. Attenuation effects are considered and the cases where assumptions of pure elastic response will lead to errors are discussed. 941016 Magnitude-distance relations for liquefaction in soil from earthquakes Papadopoulos, G A; Lefkopoulos, G Bull Seismol Soc Am V83, N3, June 1993, P925-938 At least 30 cases of liquefaction due to earthquakes of magnitude 5.8-7.2 have been recorded for Greece since 1767. Liquefaction usually occurs in the epicentral area. Maximum epicentral and fault distances for liquefaction, Re and Rf, generally increase with magnitude, M. Equations approximating these limiting distances as a function of M are proposed. The Greek data, other recent data, and the historical compilation data of Ambraseys (1988) are combined and analysed and slight modifications to the Ambraseys magnitude-distance relations suggested. 941017 Analysis of water level changes induced by fault creep at Parkfleld, California Rudnicki, J W; Yin, J; Roeloffs, E A J Geophys Res 1/98, NB5, May 1993, P8143-8152 Five slip-related water level changes in a well 460m from the San Andreas Fault near Parkfield have been studied. Rapid drawdown (It 8 hours) then slow recovery over 15-30 days was observed. Recovery can be modelled by pore fluid diffusion due to a plane strain dislocation in a fluid saturated elastic solid. Satisfactory agreement is obtained by assuming slip occurs instantaneously and extends infinitely to the southeast of the well. Magnitudes and distributions of slip inferred from water level changes show varying degrees of agreement with creepmeter data, suggesting surface slip near creepmeters may differ significantly from that near the 240m depth of the well.

941018 Liquefaction-induced ground damage in Dagupan in the July 16, 1990 Luzon earthquake Ishihara, K; Acacio, A A; Towhata, I Soils Found V33, N1, March 1993, P133-154 Distribution of ground damage following the 1990 earthquake has been investigated in Dagupan City. Liquefaction occurred in two geomorphologically different areas, old river channels and point bar deposits. Their common feature was an unliquefiable silty surface layer over loose sand. Simple analysis indicates it is the upper part of the sand layer which liquefies. Penetration test data are used to evaluate the relation between thicknesses of the unliquified and liquefied layers and the resulting damage. Residual strength values back calculated from analysis of lateral spreading are consistent with those from other sources. 941019 Seismic response variability of soil sites Yeh, C H; Rahman, M S Proc 6th ASCE Speciality Conference on Probabilistic Mechanics and Structural and Geotedmicul Reliability, Denver, 8-10 July 1992 P392-395. Publ New York: ASCE, 1992 Seismic response of a site has implications both for ground motion amplification and soil liquefaction. Base motion generated by an earthquake is a random process and the site itself will be inhomogeneous and randomly varying. Both of these will lead to a wide range of variability of site response. This is studied using a direct Monte Carlo simulation based finite element analysis. Effects of parameters governing the randomeness of shear modulus on the variability of response are evaluated. 941020 Differential motions in sedimentary valleys Papageorgiou, A S Proc 6th ASCE Speciality Conference on Prohabilistic Mechanics and Structural and Geotedmicul Reliability, Denver, 8-10 July 1992 P400-403. Publ New York: ASCE, 1992 One of the most important effects of sedimentary valleys on earthquake ground motions is the generation of valleyinduced waves which propagate back and forth within the sediments. Differential motions due to incident seisic waves in asymmetric wedge-shaped valleys are examined. Very strong response is seen to the horizontally propagating P wave (SP wave) which is induced when SV waves, incident at a critical angle, interact with the free surface of the half space.

Hydrogeology Groundwater See also: 941128, 941132, 941141, 941144, 941223 941021 Estimation of dispersion parameters for two-dimensional plumes Zou, S; Parr, A Ground Water V31, N3, May-June 1993, P389-392 Analytical methods are presented for determination of longitudinal and transverse dispersivities when a 2D plume is generated from slug injection of a tracer in a uniform groundwater flow field. One is for use when data are available from two