Fiber sensing, also known as distributed fiber sensing (DFS), falls into three primary sensing capabilities, Bausor explained: Temperature, strain, and vibration. These can be applied across a wide variety of use cases. Each one requires a slightly different underlying. If 5G is the neural conduction of the digital age and AI the super brain, fiber sensing serves as the quietly growing peripheral nerves. In 2023, a group from California Institute of Technology, collaborating with Google, achieved the world's first commercial submarine cable-based second-level. Distributed and quasi-distributed fiber optic sensors are systems that connect opto-electronic interrogators to an optical fiber (or cable), converting the fiber to an array of distributed sensors. Fiber optics replace traditional copper sensor cabling and sensors with low-profile, lightweight optical fiber and uses light interacting with that fiber to measure physical characteristics. We present here the recent advance in exploring new detection mechanisms, materials, processes, and applications of fiber optic sensors. Introduction In this Special Issue, we aim to focus on all aspects of the recent. Despite an ever‐growing library of ground‐breaking studies, questions remain about the potential of fiber‐optic sensing technologies as tools for advancing if not revolutionizing earthquake‐hazards‐related research, monitoring, and early warning systems.