Rayleigh wave H/V amplitude ratio inversion for one-dimensional elastic Earth structure

Abstract

This thesis delves into the utilization of Rayleigh wave H/V amplitude ratios for subsurface property inversion. Elastic Earth properties and their influence on seismic wave propagation are of great interest in various scientific and societal studies related to engineering, groundwater research, environmental studies, and even hazard definition and mitigation. The Rayleigh wave H/V amplitude ratio is inherently frequency-dependent and sensitive to subsurface properties, such as S-wave velocity, P-wave velocity, density, and thickness. Thus, the inversion of Rayleigh wave H/V ratio data at di↵erent frequencies can be employed to retrieve Earth’s subsurface properties, which is achieved here using the Gauss-Newton inversion scheme. The core of this research revolves around synthetic tests, e↵ectively resolving S-wave velocity, primarily focusing on simple geological models. Our experiments underscore the robustness of the Gauss-Newton inversion method for one-dimensional H/V inversion. However, it is essential to acknowledge the code’s limitations in handling noise and its reliance on assumptions of perfect knowledge. Promising future directions include adapting the code for real-world data and exploring simultaneous inversion for P-wave velocity, S-wave velocity, and density, along with investigating joint phase velocity and H/V amplitude ratio inversion. This research not only enhances our understanding of subsurface property exploration but also bridges the gap between synthetic experiments and practical applications.