Date of Award

2026

Degree Type

Thesis

Degree Name

Master of Science in Ocean Engineering

Department

Ocean Engineering

First Advisor

Aser Abbas

Abstract

Elevated ground motion amplitudes at individual stations are commonly observed in earthquake datasets, yet the physical causes of these residuals are often not explicitly identified. This study investigates two seismic monitoring stations in southeastern New York that recorded amplified motions during the 2024 Mw 4.8 Tewksbury, New Jersey earthquake. A consistent set of established geophysical methods -- including multichannel analysis of surface waves (MASW), passive ambient noise arrays (MAM), stochastic inversion, horizontal-to-vertical spectral ratio (HVSR) analysis, and directional spectral ratio techniques -- was applied to directly characterize site conditions and identify the mechanisms contributing to amplification.

Results show that elevated amplitudes can arise from different physical processes depending on site conditions. At one site, amplification is associated with resonance within a thick sedimentary column, while at another, amplification occurs in a shallow bedrock environment and is controlled by topographic geometry and directional wavefield interaction. These findings demonstrate that similar residual behavior can be produced by distinct mechanisms that are not uniquely represented by simplified site parameters.

The study highlights a practical framework for interpreting ground motion residuals through site-specific characterization. By linking observed amplification patterns to underlying physical controls, the results provide insight into how additional site descriptors, such as sediment thickness, resonance frequency, or topographic metrics, may be used to refine representation of site effects in future ground motion prediction equations.

Share

COinS
 
 

To view the content in your browser, please download Adobe Reader or, alternately,
you may Download the file to your hard drive.

NOTE: The latest versions of Adobe Reader do not support viewing PDF files within Firefox on Mac OS and if you are using a modern (Intel) Mac, there is no official plugin for viewing PDF files within the browser window.