Quick Search:    advanced search

GSW Home   GeoRef Home   My GSW Alerts   Contact GSW   About GSW   Journals List   Help

This Article Figures Only Full Text Full Text (PDF) Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (2) Citing Articles via Google Scholar Google Scholar Articles by Barnaba, C. Articles by Romanelli, M. Search for Related Content GeoRef GeoRef Citation

Site Effect of the Strong-Motion Site at Tolmezzo-Ambiesta Dam in Northeastern Italy

¹ Istituto Nazionale di Oceanografia e di Geofisica Sperimentale
Dip. C.R.S. Via Treviso, 55 - C.P.1, Cussignacco (Udine), Italy
cbarnaba{at}inogs.it
epriolo{at}inogs.it
avuan{at}inogs.it
mromanelli{at}inogs.it

A spectral analysis of strong-motion data and ambient noise at the Tolmezzo-Ambiesta dam accelerograph (TLM1) site is performed to explain the high horizontal peak acceleration of 0.36g recorded during the M_w 6.4, 6 May 1976 Friuli (northeastern Italy) earthquake. The spectral response of the accelerographic site is estimated from the mainshocks and aftershocks of the 1976 seismic sequence by different techniques. In addition, new seismic data are used to characterize the near- surface S-wave velocity distribution versus depth at TLM1 by means of an analysis of the phase-velocity dispersion of Rayleigh waves. An average, spectral amplification curve is computed for TLM1, whose mean value is at about 1.5. It features two main lobes of amplification with peaks at 2–3.5 Hz and 6–7 Hz that are explained, by the horizontal-to-vertical spectral ratio (HVSR) of noise measurements, as the effects of the vibration of a nearby relief and the dam-reservoir system, respectively. When the site response is evaluated from earthquake recordings, the frequency of resonance due to near-surface S-wave velocity profile at about 5 Hz is strongly attenuated in comparison with the 6–7 Hz peak due to the dam-reservoir system. Finally, by filtering the site effects of the 1976 record, the acceleration peak is reduced from the original value of 349.99 cm/sec² to 188.76 cm/sec².

This article has been cited by other articles:

				M. Massa, P. Morasca, L. Moratto, S. Marzorati, G. Costa, and D. Spallarossa Empirical Ground-Motion Prediction Equations for Northern Italy Using Weak- and Strong-Motion Amplitudes, Frequency Content, and Duration Parameters Bulletin of the Seismological Society of America, June 1, 2008; 98(3): 1319 - 1342. [Abstract] [Full Text] [PDF]

				P. L. Bragato, G. Laurenzano, and C. Barnaba Automatic Zonation of Urban Areas Based on the Similarity of H/V Spectral Ratios Bulletin of the Seismological Society of America, October 1, 2007; 97(5): 1404 - 1412. [Abstract] [Full Text] [PDF]