Near-surface variations captured by continuous DAS and surface orbital vibrators monitoring

This study explores the impact of near-surface property variations on seismic data collected using Distributed Acoustic Sensing (DAS) at the Otway International Test Centre in southeast Australia. Over a twenty-month period, continuous measurements were obtained from permanently deployed fibre-optic cables and Surface Orbital Vibrators (SOVs). By focusing on direct wave signatures, the research captures how daily and seasonal weather changes alongside dynamic changes in groundwater levels impact seismic data attributes, such as signal repeatability, travel time, and amplitude. The results emphasize the importance of continuous seismic monitoring for understanding the near-surface effects, which can vary considerably over short and long timescales. In addition to demonstrating the feasibility of autonomous data acquisition and remote monitoring, the study underlines the broader practical implications for exploration and permanent reservoir monitoring.