Evaluation of site response characteristics of King Abdulaziz City for Science and Technology, Saudi Arabia using microtremors and geotechnical data

Abstract

Microtremor measurements become one of the widely accepted tools to evaluate the site response characteristics since the last two decades. These measurements have been conducted at four sites inside King Abdulaziz City for Science and Technology (KACST), Riyadh city, Saudi Arabia to estimate the resonance frequency and the associated amplitude of sediments. Microtremor measurements have been recorded for 24 h with a sampling frequency of 100 Hz in the range from 0.2 to 25 Hz band-pass filter. Origin of the identified peaks has been tested. The estimated peaks are correlated with borehole geotechnical data: (1) the first peak with an average frequency of 8.25 Hz that reflects the impedance contrast between the uppermost surface soil and the underlying completely weathered limestone and (2) the second peak of 1.43 Hz which corresponds to the impedance contrast between the completely weathered limestone and the underlying limestone rocks. In addition, the relation between sediment thickness and resonance frequency has been assessed. Based on the results of this study, it can be stated that microtremor measurements are capable to estimate thickness of sedimentary overburden. These results will support for seismic safety in case of civil engineering constructs in KACST area.

A Quantitative Site-Specific Classification Approach Based on Affinity Propagation Clustering

“…Many researchers utilized the microtremor measurements in many parts of Saudi Arabia for estimating the site response, in terms of predominant frequency and concluded that the technique is very promising particularly for the densely populated areas like the new urban planning and reducing the vulnerability on the existing civil constructions (Al-Malki et al, 2015;Alyousef et al, 2015). Hence, this study would be the rst indispensable step, which will provide insights into the seismic site response of the KSU campus for designing and implementing phases of new and development expansions.…”

“…Panah et al (2002), obtained classi cation based on the HVSR method and validate the application for site dominant frequency estimation and site classi cation. In spite of its limitations, many researchers (e.g., Qaisar et al, 2008;Wallinget al, 2009;Fnais et al, 2010) have proved from the research that HVSR method is a robust technique and preliminary step toward site characteristics estimation and microzonation in the areas of interest (Ibs-von Seht and Wohlenberg, 1999;Choobbasti et al, 2013;Moustafa, 2015;Al-Malki et al, 2015;Alyousef et al, 2015;Hellel et al, 2019;Clementeet al, 2019;Tian et al, 2019;Anbazhagan et al, 2019).…”

A Quantitative Site-Specific Classification Approach Based on Affinity Propagation Clustering

“…These activities intensified the need for site response evaluation. Many researchers utilized the microtremor measurements in many parts of Saudi Arabia for estimating the site response, in terms of the predominant frequency and concluded that the technique is very promising particularly for the densely populated areas like the new urban planning and reducing the vulnerability on the existing civil constructions [25], [26]. Hence, this study would be the first indispensable step, which will provide insights into the seismic site response of the KSU campus for designing and implementing phases of new and development expansions.…”