The Great Gulf of Aqaba 1995 Earthquake Design Response Spectra over Sinai Peninsula and Some Jordanian Soils

Mohamed A Gamal,Ahmed Abdelwahed

doi:10.4236/ijg.2019.104027

Abstract

The Gulf of Aqaba area is considered one of the most terrific touristic areas in the Middle East. The aim of the present work is to determine the amount of seismic hazards that the constructions may suffer due to seismic activities. This is done by determining the design response spectrum for this area from available earthquake response spectra, then taking into consideration the soil response for some Egyptian and Jordanian soils. The main shock of the November 22, 1995, the Gulf of Aqaba and its aftershocks were mainly used in producing the design response spectrum. This earthquake was considered as the biggest earthquake that hit this area since 160 years. Its magnitude was determined as Mw = 7.2. Thousands of aftershocks with intermediate magnitude followed the main shock, such as the aftershock that occurred on November 23, 1995 with a local magnitude of ML = 5.4. The best estimate of the focus location was determined in the area between Dahab and Nuweiba cities. This great earthquake was felt in Lebanon, Syria and Israel in the North and Egypt, Saudi Arabia and Sudan in the South. The touristic areas surrounding the Gulf of Aqaba were mostly affected. Different accelerograms for this great earthquake were collected and soil responses spectra for Sinai Peninsula and some Jordanian soils were calculated. The design response spectrum shows an average spectral acceleration of about 250 cm/sec2 for frequency range between 1 - 10 HZ. Soil Amplifications were then calculated using Microtremors site response technique and maximum spectral accelerations filtered by the soil were in range between 120 - 450 cm/sec2 for the study area. The analysis presented here is intended to be used in the future to allow reducing the seismic risk, help in proper structural design and detailing of buildings and structures to account for beam-column connections and shear reinforcement.

Highlights

It is well known that after the earthquake occurs, the areas that experienced the maximum peak ground acceleration (PGA) are not necessarily showing the maximum damage
This is done by determining the design response spectrum for this area from available earthquake response spectra, taking into consideration the soil response for some Egyptian and Jordanian soils
The present work is very important for two reasons: one is that it uses the spectral acceleration which is very rare in this area to accurately show acceleration values carried on which frequencies, second to make soil frequency analysis to know the amount of energy that will enter this soil and the structures

Summary

Introduction

It is well known that after the earthquake occurs, the areas that experienced the maximum peak ground acceleration (PGA) are not necessarily showing the maximum damage. The fundamental natural frequency of the soils and structures is very important in seismic hazard assessment For this reason, the concept of the response spectra was introduced. The concept of the response spectra was introduced This important engineering quantity is determined from the original earthquake ground motion by using narrow band-pass filters that acts like simple oscillators or structures [1]. The response spectrum is very useful in the design of buildings, because we can deal with structures like simple damped harmonic oscillators and show the maximum corresponding acceleration response that the structures will suffer during earthquakes, based on its natural frequency, and determine the magnitude of force that will affect these structures during earthquake excitation [2] [3]. A final maximum spectral acceleration map was introduced by filtering the spectral acceleration by soil taking into consideration the amplification values for each soil

Objectives

Methods

Conclusion