The increasing availability of strong-motion accelerograms, and the relative ease with which they can be obtained compared to synthetic or artificial records, makes the use of real records an ever more attractive option for defining the input to dynamic analyses in geotechnical and structural engineering. Guidelines on procedures for the selection of appropriate suites of acceleration time-series for this purpose are lacking, and seismic design codes are particularly poor in this respect. Criteria for selecting records in terms of earthquake scenarios and in terms of response spectral ordinates are presented, together with options and criteria for adjusting the selected accelerograms to match the elastic design spectrum. The application of both geophysical and response spectral search criteria is illustrated using compatible scenarios, and the selected records are analysed and adjusted to produce suites of acceleration time-series suitable for dynamic analyses. The paper concludes with suggestions for mak...

The use of real earthquake accelerograms as input to dynamic analysis

First European Conference on Earthquake Engineering and Seismology

The aim of this work is to check the stability of the horizontal-to-vertical spectral ratios (HVSRs) calculated at the Venosa station site (Italy). This site lies over a layer of anthropogenic fill (4 m thick), a rigid layer of conglomerates (15 m thick), and a thick layer of clays (about 300 m thick) above the seismic bedrock. The velocity inversion, which takes place at the conglomerates-clays interface, is of main importance for the amplification behavior of this site. We have analyzed nearly 2 years of data, composed of 244 triggered noise records and 44 earthquakes. The results obtained by the two data sets show different site-response characteristics. In particular, the earthquake HVSR is not deamplified in the frequency range 1-8 Hz like the triggered noise HVSR. To find out the origin of this difference, we modeled both the triggered noise and the earthquakes, taking advantage of an improved ver- sion of the Thompson-Haskell propagation matrix method. The differences between triggered-noise- and earthquake-amplification functions might be explained by the difference in composition and propagation of the seismic wave fields. Moreover, we 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.

http://basin.earth.ncu.edu.tw/download/courses/seminar_MSc/2006/1005-2_Analysis%20and%20Modeling%20of%20HVSR%20in%20the%20Presence%20of%20a%20Velocity%20Inversion_The%20Case%20of%20Venosa,%20Italy%20.pdf

Analysis and Modeling of hvsr in the Presence of a Velocity Inversion: The Case of Venosa, Italy

Seismic response of structures and infrastructure facilities during the Lefkada, Greece earthquake of 14/8/2003

Stiff soil amplification effects in the 7 September 1999 Athens (Greece) earthquake

Evidence of nonlinear site response in horizontal-to-vertical spectral ratio from near-field earthquakes

On 15 June 1995, an earthquake of moment magnitude M w =6.4 occurred in the western part of Corinthiakos Gulf, Greece, causing the loss of 26 human lives and inflicting considerable damage mainly in the northern part of Peloponnessus. Particularly damaged was the town of Aigio with its environs. The only strong motion instrument in operation at the time of the mainshock in the town of Aigio recorded a horizontal acceleration as high as 0.54 g—the highest ever recorded in Greece—in the vicinity of a collapsed building. The main characteristic of the recorded strong ground motion is the pulse-like shape of its most intensive part, with a period of about 0.45 sec. The macroseismic observations are in good agreement with the distribution of the peak horizontal acceleration—recorded at epicentral distances from 18 km to 78 km, and both sets of data imply anisotropic radiation of seismic waves by the source. The tremor and its largest aftershock (M w =5.6), which followed about 15 minutes later, caused total or...

P. P. Dimitriu

Papers

Evidence of nonlinear site response in horizontal-to-vertical spectral ratio from near-field earthquakes

The aigio (greece) seismic sequence of june 1995: seismological, strong motion data and effects of the earthquakes on structures