Earthquake vulnerability assesment for khartoum state using nakamura

Abstract

Abstract Earthquake is considered to be one of the most natural hazards affecting human being due to its sudden happening in addition to what finally result out of its occasional happening of human and artificial losses. Various deferent studies and field observations which took place for the site which was physically subjected to destructive earthquake that there is a different cfiect on the degree of influence in spite of the fact of its occurrence on the same site area out of the earthquake, and that there very clear relation between earthquake destructively percentage and the soil natureof same site. Generally the surface layers are normally exposed to vibration by natural forces (storm, sea wave) and artificial forces (human, trafiic, factory). Natural induce tremor of long period (2, 3 sec to 20), called microseismic, artificial force create tremors of shorter period, and is called microtremor. This technique is called Nakamura technique. The study area is located between longitude 430000-480000 casting and 1690000-1760000 northing in Khartoum state, being the capital of Sudan, and it is out of the basic center, for all strategic plans and important development projects in addition to existing and availability of many manufacturing as well as Khartomn refinery. The overall objective of this study is to determine the fundamental frequency, amplification and vulnerability for every measurement points. To enable both civil and architectural engineer to benefit out this study in strategic development project. The results shows two spectral amplitudes for site 2 and 7, on which the first peak is probably associated with the site response characteristics of sediments. The other sites show one peak of the spectral amplitudes which are obvious effects sediments. Specual ratios show different principle peak from 0.3 to 3.9 Hz for all sites. Site east Tebna, west El Sumra , which is located on high fractured granitic rocls, shows deferent values and shape of spectral ratio. A map that reflected the fundamental characteristic of possible side effects in the city. IV