HR: 0830h
AN: S41D-06    [Abstracts]
TI: Effects of Topography on Earthquake Ground Motions Observed During the 2004 Parkfield Earthquake
AU: * Wang, G
EM: gwang@ncat.edu
AF: Applied Geophysical Science Laboratories, North Carolina A&T State University, 1020 East Wendover Ave., Greensboro, NC 27411 United States
AU: Tang, G
EM: gtang@ncat.edu
AF: Applied Geophysical Science Laboratories, North Carolina A&T State University, 1020 East Wendover Ave., Greensboro, NC 27411 United States
AU: Burbach, G N
EM: burbach@ncat.edu
AF: Applied Geophysical Science Laboratories, North Carolina A&T State University, 1020 East Wendover Ave., Greensboro, NC 27411 United States
AU: Jackson, C R
EM: cjackson@ncat.edu
AF: Applied Geophysical Science Laboratories, North Carolina A&T State University, 1020 East Wendover Ave., Greensboro, NC 27411 United States
AU: Lin, Q
EM: qlin@ncat.edu
AF: Applied Geophysical Science Laboratories, North Carolina A&T State University, 1020 East Wendover Ave., Greensboro, NC 27411 United States
AB: During recent earthquakes such as 1994 Northridge, 1999 Izmit, 1999 Chi-Chi events, unusually large ground motions were recorded near the crests of ridges. Some concentrated patterns of structural damage relative to topography were also observed. These observations have suggested that surface topography significantly affect ground motions. However, the effects of topography often mix with the effects of path and geologic conditions. In order to properly quantify the topographic effects, crest motions must be evaluated relative to comparable free-field motions under same site conditions. The September 28, 2004 Parkfield earthquake (M_w 6) supplied an unprecedented opportunity of studying the topographic effects. It is an anticipated event that came 15 years later than predicted date. Very densed instruments had been installed in this region to capture the anticipated event. A large number of records are available from instruments installed on hills close to the epicenter. We will study the effects of topography on strong ground motions in this work. The main purpose of this study is to isolate the influence of the topographic effects from the effects of wave propagation, geologic amplification, as well as soil-structure interaction.
DE: 7212 Earthquake ground motions and engineering
DE: 7223 Seismic hazard assessment and prediction
DE: 7260 Theory and modeling
DE: 7294 Instruments and techniques
SC: Seismology [S]
MN: 2005 Joint Assembly