Article ID | Journal | Published Year | Pages | File Type |
---|---|---|---|---|
9642578 | Soil Dynamics and Earthquake Engineering | 2005 | 7 Pages |
Abstract
We evaluate the influence of topography on motions recorded at the base and crest of an approximate 3H:1V, 20Â m single-faced slope. The motions were recorded during the 1983 Coalinga earthquake mainshock and two aftershocks. Mainshock peak accelerations at the crest and base transverse to the slope face were 0.59 and 0.38Â g, respectively. The spectral amplification of crest motion occurred across Tâ0-2Â s. Differences between the crest/base motions are postulated to result principally from soil-structure interaction (base instrument is in a structure), variations in local ground response, and topography. Transfer functions quantifying soil-structure interaction (SSI) effects are evaluated and the base motion is modified at short periods to correct it to an equivalent free-field motion. The different levels of ground response at the crest and base are identified based on location-specific measurements of soil shear wave velocities. Differences between crest/base motions not accounted for by SSI or differential ground response are attributed to topographic effects. By these means, topographic spectral amplification (i.e. amplification relative to level ground conditions) is estimated to be about 1.2 at the crest and about 0.85-0.9 at the base across the period range Tâ0.4-1.0Â s.
Related Topics
Physical Sciences and Engineering
Earth and Planetary Sciences
Geotechnical Engineering and Engineering Geology
Authors
Jonathan P. Stewart, Shawn E. Sholtis,