Earth-prints repository, logo   DSpace

About DSpace Software
|earth-prints home page | roma library | bologna library | catania library | milano library | napoli library | palermo library
Please use this identifier to cite or link to this item: http://hdl.handle.net/2122/854

Authors: Castro, R. R.*
Gallipoli, M. R.*
Mucciarelli, M.*
Title: An attenuation study in Southern Italy using local and regional earthquakes recorded by seismic network of Basilicata
Issue Date: 2004
Series/Report no.: 47 (5)
URI: http://hdl.handle.net/2122/854
Keywords: seismic attenuation
Southern Italy
Q
Abstract: We determined a set of empirical functions that describe the spectral amplitude decay of S-waves with distance in Southern Italy. We analyzed 32 earthquakes with magnitudes ML 2.0-5.4 and hypocentral distances ranging between 12 and 216 km. We obtained attenuation functions for 14 frequencies(1.0< f<20.0 Hz). We compared these functions with average non-parametric attenuation functions reported by Castro et al. (1999) for different regions of Italy, and we observe that at low frequencies (f<5.0 Hz) the spectral amplitudes from earthquakes in Southern Italy decay faster than the average. However, at high frequencies ( f > 5.0 Hz), the spectral amplitudes are above the average. At higher frequencies ( f > 10 Hz), the attenuation functions obtained for Southern Italy are slightly above the standard deviation of the average attenuation functions. It is possible that in this frequency range (10-20 Hz) site effects may influence the amplitude decay. In order to quantify the attenuation of the S-waves, we estimated the quality factor Q modeling the empirical attenuation functions using the following parametric form: A( f , r)=10/r b·e- pfR/Q ß; where 1.6 = f = 10.0 Hz is the frequency band with minimum effect of instrument and site response, r = 120 km is the distance range where the rate of decay of the spectral amplitudes is approximately constant, R=(r-10) and ß=3.2 km/s. We found that the exponent b=1.0±0.2 in the frequency band analyzed and Q shows a frequency dependence that can be approximated by the function Q=32.1 f 1.7.
Appears in Collections:04.06.99. General or miscellaneous
Annals of Geophysics

Files in This Item:

File SizeFormatVisibility
07RamnCastro.pdf1.68 MBAdobe PDFView/Open


Items in DSpace are protected by copyright, with all rights reserved, unless otherwise indicated.


Share this record
Del.icio.us

Citeulike

Connotea

Facebook

Stumble it!

reddit


 

Valid XHTML 1.0! ICT Support, development & maintenance are provided by CINECA. Powered on DSpace Software. CINECA