1 Department of Civil Engineering, Technical University of Denmark 2 Section for Structural Engineering, Department of Civil Engineering, Technical University of Denmark 3 University of California at Berkeley
Spatial variability of near-fault strong motions recorded by the US Geological Survey Parkfield Seismograph Array (UPSAR) during the 2004 Parkfield (California) earthquake is investigated. Behavior of the lagged coherency for two horizontal and the vertical components is analyzed by separately examining the decay of coherency with frequency and distance. Assumptions, approximations, and challenges that are involved in estimation of the coherency from recorded data are presented in detail. Comparison of the UPSAR coherency estimates with coherency models that are commonly used in engineering practice sheds light on the advantages and limitations of different approaches to modeling the coherency, as well as on similarities and differences in the spatial variability exhibited by seismic ground motion arrays at different sites. © 2013 John Wiley & Sons, Ltd.
Earthquake Engineering and Structural Dynamics, 2014, Vol 43, Issue 5, p. 641-659
Coherency estimation; Ground motion array; Lagged coherency; Spatial variability
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