Influence of Active Faults on the Site Characteristics at Suez Canal area, Egypt

Abstract

Faults represent the primary mechanical discontinuities of the elastic– brittle Earth's upper crust. Active faults are considered the reason for many earthquakes and tend to occur near tectonic plate boundaries. Earthquakes are one of the natural disasters that not only disturbed the life pattern, but also cause massive losses of life, property and interrupted the process of development. Therefore, earthquakes disaster prevention and reduction strategy are a global concern today. Seismic wave propagation in the upper layers of the earth's crust controls the spread of the earthquake disaster in an area (Aggarwal et al., 2003). The aim of seismic response analysis is to determine the effect of seismic waves on a particular site, as a seismic hazard or risk depends on the seismic source, the function of transfer media, local geology, type of structures and soil structure interaction (Okamoto et al. 1973). The main objectives of the present work are the mitigation of earthquake damages and anticipate the future healthy development of the buildings and structures in the Suez Canal area through the following main points: - Analysis of digital data with modern methods to determine the source mechanism of the moderate magnitude earthquakes that have been recorded recently by the Egyptian National Seismological Network (ENSN) depending on the polarity of the first motion of P-wave and amplitude ratios during the period from 2009 to 2015. - Estimation of fundamental frequencies and H/V amplitudes for different sites at Suez, Ismailia, and Port Said cities in the study area. Summary and Conclusions 135 - Estimation of Shear-wave velocity profiles at shallow depths using Multichannel Analysis of Surface Waves (MASW) method. - Determination of shear-wave velocity structure at much deeper layers using the array seismic technique. - Estimation of strong ground motion parameters such as peak ground acceleration at several sites depending on local site effect on the study area. The study area extends from latitudes 29˚90'N to 31˚30'N and longitudes 32˚00'E to 33˚80'E. This thesis consists of four chapters Chapter I presents an introduction, datasets, methodology, and the geologic and tectonic setting of the study interest area. They are summarized as she study area comprises three main cities: Suez, Ismail, and Port Said and includes a variety of anthropogenic activities such as power plants, tunnels, irrigation canal, industrial centers, agricultural lands and pipelines as well as new urbanization. The Suez Canal is the most commercially utilized and the longest excavated waterway in the world. The Suez Canal provides savings on distance, time of sailing and costs of transportation. The area around the Suez Canal selected for the current study due to the strategic importance and the significant investments that are carrying out at the present time and future. The Study area is affected by small to moderate earthquake activity. The most damaged earthquakes experienced surrounding area of Suez Canal are:- Shadwan earthquake in 1969 with magnitude Mw=6.9 (Maamoun and El-Khashab, 1978), Gulf of Aqaba earthquake on 22 November 1995 with Mw= 7.3 (Marzouk, et al., 1996), the very close two events occurred on 18 and 22 of July 2014 near Suez City, with local magnitude (ML=4.0) and (ML=4.3) (NRIAG, 2014) respectively, as well as Gulf of Aqaba earthquake in 2015 (ML=5.2) (NRIAG, 2015), Hagul earthquake (ML=3.8) in 2007 Summary and Conclusions 136 (Abou El-enean et al., 2010), and earthquakes of Mediterranean offshore (e.g., Alexandria earthquake in 1955, Ms=6.8 (Rothe, 1969) and Cyprus earthquake in 1996, Mw=6.8 (Abou El-enean, 2007).