Application‑level segmentation of the Fiber Optic Distributed Acoustic Sensing market reflects a diversified demand profile. In Oil & Gas, DASS enables leak detection, flow assurance, and perimeter security for extensive pipeline networks, representing the largest revenue slice at approximately 30 % of the market. Transportation—principally railway and highway monitoring—leverages high‑resolution acoustic signatures to detect intrusions, track integrity, and support predictive maintenance, contributing about 25 % of total sales. Security deployments, including critical‑infrastructure perimeter surveillance and border monitoring, account for roughly 20 % as governments and enterprises adopt DASS for its low‑visibility, long‑range detection capabilities. The Energy segment—covering power‑line health monitoring and substation condition assessment—captures near 15 % of market value, driven by the need for grid resilience and outage prevention. Finally, Environmental applications such as seismic activity tracking, landslide warning, and wildlife migration studies comprise the remaining 10 %, reflecting emerging research‑driven adoption. This application taxonomy illustrates how each vertical sustains distinct growth vectors within the overall market.