Detection of local site effects through the estimation of building damages

Abstract After the Umbria Marche seismic sequence of September–October 1997, an extensive microzoning study was conducted, from October 1997 to May 1998, to detect the zones where the ground motion was amplified because of local geological and geomorphological settings. The goal of the investigation was to return amplification coefficients to local authorities for the post-seismic reconstruction and repairing of pre-existing buildings, by examining the seismic behaviour of the most damaged 60 villages. The analysis consisted in the application of well known computer codes and the results were arranged as reference table, used to assign the amplification coefficients to the rest of damaged localities. The present study has the aim of evaluating the accuracy of that methodology, following a completely different approach. The actual damages, detected by an aerial photo interpretation, are compared to the theoretical damages estimated through empirical curves, obtained from the analysis of recent Italian earthquakes. This approach was reliable enough to calibrate the results of the microzoning study and appropriate when an immediate assessment of the damage is required, to assign funds and estimate the amplification zones, that need to be investigated in finer detail.

[1]  Charles A. Langston,et al.  Structure under Mount Rainier, Washington, inferred from teleseismic body waves , 1979 .

[2]  K. Campbell,et al.  NEAR-SOURCE ATTENUATION OF PEAK HORIZONTAL ACCELERATION FROM WORLDWIDE ACCELEROGRAMS RECORDED FROM 1957 TO 1993 , 1994 .

[3]  F. Calamita,et al.  Structural styles, chronology rates of deformation, and time-space relationships in the Umbria-Marche thrust system (central Apennines, Italy) , 1994 .

[4]  David M. Boore,et al.  SEA99: A Revised Ground-Motion Prediction Relation for Use in Extensional Tectonic Regimes , 2005 .

[5]  F. Pergalani,et al.  Seismic microzoning of the area struck by Umbria–Marche (Central Italy) Ms 5.9 earthquake of 26 September 1997 , 1999 .

[6]  W. B. Joyner,et al.  ESTIMATION OF RESPONSE SPECTRA AND PEAK ACCELERATIONS FROM WESTERN NORTH AMERICAN EARTHQUAKES: AN INTERIM REPORT PART 2 , 1993 .

[7]  F. Sabetta,et al.  Estimation of response spectra and simulation of nonstationary earthquake ground motions , 1996, Bulletin of the Seismological Society of America.

[8]  J. Lawrence Von Thun,et al.  Earthquake engineering and soil dynamics II : recent advances in ground-motion evaluation : proceedings of the specialty conference , 1988 .

[9]  George W. Housner,et al.  Spectrum Intensities of Strong-Motion Earthquakes , 1952 .

[10]  Analisi dei fenomeni franosi di crollo e del danneggiamento agli edifici indotti dalla sequenza sismica dell'Umbria - Marche (settembre - ottobre 1997) , 2001 .

[11]  Marco Menichetti,et al.  Seismotectonic zoning in east-central Italy deduced from an analysis of the Neogene to present deformations and related stress fields , 1994 .