Master Thesis defense by Lana Zupancic

Title: Shallow Subsurface Imaging: A Geophysical Investigation using Integrated Methods

Abstract:
This study investigates the subsurface structure of a valley located in the northern segment of the Gulf of Aqaba (Arabian Peninsula) using seismic records from advanced seismometers (ZLand types) with 3-component nodes and onboard GPS timing. A long 7.2-kilometer seismic profile is acquired perpendicular to the Gulf shoreline in the currently under-development NEOM city. The main purpose is to map the underlying faults and gauge the depth of the basement underneath this locality.
The multichannel analysis of surface waves (MASW) technique is used for the analysis of surface waves and uses the dispersion of surface waves for the determination of a 2D shear-wave profile. In this study, surface waves were generated through a seismic source, which is a 950 kg weight drop.
MASW is used to focus on the relatively shallow subsurface sedimentary succession and basement structure in this region. After applying a quality control and dispersion analysis to the dataset, a 2D shear-wave tomogram (SWT) is generated and compared to a P-wave velocity tomogram (PWT) from a recent study.
Both the SWT and the PWT show that the sediments are thicker on the western side of the tomogram and get thinner as you move toward the east. The PWT shows four faults, while they are not that visible on the shear-wave tomogram. On the other hand, disruptions of and around dispersion curves occurred around shot gathers where faults were anticipated (and imaged by PWT), which may represent a new clue for the presence of the fault system. These findings provide insights into the geological structure of the NEOM area and have implications for future seismic hazard assessments.

Supervisor: Klaus Mosegaard