Writers : ghafouri,Mohammad;lashkaripour,Gholamreza;Hafezi Moghadas,Naser;Yazdanfar,Rouzbeh;Akbari,Majid
Refference : 11th Symposium Of Geological Society Of Iran - Mashhad, Ferdowsi University
Publishing Year : 1386

Abstract :

Soil Type strongly affects earthquake hazards, soils may amplify or de-amplify ground motions.
Therefore, the actual level of ground shaking experienced at a given site from a given earthquake varies with Soil Type. The average of shear wave velocity in the first 30 m was accepted as a factor which identifies the sites potential in amplifying or de-amplifying of the seismic waves. The major building codes in throughout the world classify the sites on the basis of this factor. Therefore in the north of Mashhad by using available boreholes with more than 28.5 depth N-SPT data first a relation was established between SPT value and shear wave velocity, then from available boreholes in the area those which had more than 28.5 depth were selected for this study. For selected boreholes shear wave velocity was calculated in different depths and vs30 values were obtained by using of vs30=ndi/ndi/vi formula for every borehole. Soils in this area were classified according to Iranian Code of Practice for Seismic Resistance Design for Buildings: Standard No: 2800-5. Therefore three types of soil were identified in the study area. The most parts of this area are covered by type II soils with 88 percent extent. Vs30 zonation map was plotted and its variation is considered along three selected scan lines.