الفهرس | Only 14 pages are availabe for public view |
Abstract Seismological stations network are the main tool for earthquake studies and hazard assessment, So that it is very important to improve the network stations efficiency. The observed seismic signal is a combination of source, path and local site effect which could be the dominant factor The first stage is to Study the site effect (noise level and site response ) through direct observation in the field by installing temporal seismic station -recording for one hour- in the Egyptian National Seismological Network (ENSN) station sites in northern Egypt (39 station) and using this record for Peterson model to estimate noise level in each station site, then applying Nakamura H/V(Horizontal-to-Vertical) Ratio technique to find the site response for these stations (fundamental frequencies and the corresponding amplifications) by Geopsy Software. While in second stage, five seismic profiles were accomplished in five sites in greater Cairo and used for further estimation of site response by applying the Multi Channel Analysis of Surface waves (MASW) method using Surf-seis Software. Noise level estimation shows that stations in north Egypt are suitable for earthquake observation except three stations of Nubaa, Tur 2 and Zafarana which have moderate noise level. Nakamura technique enabled us to classify the station sites according to the amplification factor as follow: low (13 stations), moderate (11 stations) and considerable amplification (12 station) which should be considered in data handling. While the MASW technique correlated well with the results Nakamura method for estimating site response up to 30 meter depth and the two techniques differ only in Myaden Station values. |