埃及东部沙漠Gasco天然气公司工程场地大地构造参数和地震灾害评估(英文)

Geotectonical Parameters and Seismic Hazard Assessment for GASCO Site,Eastern Desert,Egypt

根据埃及Gasco天然气公司工程场地的现场调查资料、地震活动性和地震灾害评估结果,对该场地进行了评估。通过浅源地震波折射勘探,对8个地震剖面上的土壤和岩石的弹性动态常数进行了分析。场地地面模型包括两层,分析表明它们具有从中值到高值的弹性动态常数,说明场地有良好的土壤条件和基岩岩性。同时,我们搜集和分析了研究区周围150 km半径范围内的历史和仪器记录地震,从构造环境、地震活动性、地质构造和主要地震的断层面解等方面进行了研究,认为场地受4个震源区的影响:苏伊士中部海湾、开罗—苏伊士地区、开罗西南和Beni-Suef地区。我们采用地震活动性统计方法并结合专家判定,确定了这些震源区内最大地震的矩震级(MW)。另外,依据场地峰值加速度(PGA)和反应谱,用随机方法对场地进行了地震灾害评估。4个震源区中, Beni-Suef地区距离工程场地最近,其PGA最大值为9.34 cm/s2,但这个值很小,表明地震不会对工程场地产生破坏性影响。最后,我们还模拟了阻尼为1%、3%和5%时的伪加速度场地反应谱。

GASCO site has been evaluated on the basis of site investigation, seismic activity and seismic hazard assessment. Shallow seismic refraction survey has been carried out to estimate the elastic and dynamic constants for soil and rock materials throughout 8 seismic profiles. The ground model at the site consisting of two layers characterized by moderate to high values of elastic and dynamic constants indicates that the site has good soil and foundation rock. Both historical and instrumental earthquakes in a circle with radius of 150 km around the proposed site were collected and precisely analyzed. The site is affected by four seismic source zones： Central Gulf of Suez, Cairo-Suez District, Southwest Cairo and Beni-Suef, based on the tectonic setting, the seismicity, geological structures and fault plane solutions of major earthquakes. Maximum earthquake moment magnitudes （ Mw ） have been identified for these source zones using seismicity statistics together with expert judgment. In addition, the stochastic approach was applied for the seismic hazard assess- ment in terms of Peak Ground Acceleration （PGA） and response spectra. It is noticed that Beni-Suef .is the nearest source to the site and the maximum PGA value produced from this seismic source reaches 9.34 cm/s2. This value is small and reflects that there is no hazardous effect to be expected at GASCO site, which indicates its validity for civil engineering purposes. The response spectra at 1%, 3%, 5% and 10% damped Pseudo-acceleration （PSA） were also simulated at the GASCO site.