Comparison of Different Site Response Estimation Technique Using Synthetic and Real Data

YingRu Wang

Abstract

Earthquake recordings will be effected by Source, Path, Attenuation and Site Response. In particular, unconsolidated sediments overlying bedrock amplify seismic motion in specific frequency bands. Various site response estimationtechniques already have been studied through synthetic and real data to quantify this site effect. This report investigated the stability of two site response estimation techniques, the horizontal-to-vertical spectral ratio (HVSR) and the horizontal-to-vertical noise ratio (HVNR), at the Venosa station site by analyzing 244 triggered noise recordings and 44 earthquakes. This site lies over a layer of anthropogenic fill, a rigid layer of conglomerates, and a thick layer of clays above the seismic bedrock. The results obtained by the two data sets show different site response characteristics. Then they modeled both the triggered noise and the earthquakes, and found that the difference between triggered-noise- and earthquake-amplification function might be explained by the difference in composition and propagation of the seismic wave fields. Moreover, they show that the nonlinear behavior of the anthropogenic fill might explain the presence of the misfit of the resonance frequency attributed to this layer between triggered noise and earthquakes.

 

References

Giacomo, D. G., M. R. Gallipoli, M. Mucciarelli, S. Parolai, and S. M. Richwalski (2006). Analysis and Modeling of HVSR in the Presence of a Velocity Inversion: The Case of Venosa, Italy, Bull. Seism. Soc. Am. 95, 2364-2372.

(Abstract)(Full text)

Coutel, F., and P. Mora (1998). Simulation-Based Comparison of Four Site-Response Estimation Techniques, Bull. Seism. Soc. Am. 88, 30-42.

(Abstract)(Full text)