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.