## 1 Introduction
### Brief Explanation of DAS  
The adoption of fiber optic technology to address subsurface monitoring problems has gained significant traction across various industries, including the petroleum sector. While most studies published using DAS as fiber optic technology have focused on fibers deployed in wells, several studies have explored oil and gas production and CO\({}_{2}\) sequestration. The implementations reported in these studies were designed for microseismic monitoring during hydraulic fracturing [20; 21], repeatable VSP imaging [10; 22; 23], or fluid flow monitoring through production [10]. A notable discovery from this research indicates the significance of installation techniques; cables securely clamped to the well's side exhibited superior performance compared to loosely laid straight fibers, and cables embedded in cement outperformed clamped cables [22]. Ideally, geophysicists should be able to use a dense array of high-resolution, multi-component receivers. However, the deployment and sustainable maintenance costs of such an array might be difficult, particularly in crowded areas where permitting permission is more challenging to maintain and theft and damage to sensors are more significant concerns. In terms of these objectives, the fiber optic cable deployment methods exhibited substantial variation, with less emphasis on standardizing installation techniques for diverse near-surface and shallow seismic recording objectives due to the high-spatial-resolution advantage compared to more concerted efforts among geoscientists engaged in downhole seismic recording [24]. Fiber optic cables can be effectively buried within a trench or even placed within an existing telecommunications conduit, mitigating potential permitting issues. Trenching burial for surface DAS measurement is the most common deployment of fiber optic cables to increase coupling with the ground due to its measurement sensitivity [7]. DAS applications for subsurface imaging have undergone great development due to the improvements in geophysics exploration, starting from the year of 2000, when the author of [25] introduced fiber optic seismic sensors to conduct field experiments. A summary of research applying DAS for geophysics exploration throughout years is illustrated in Figure 1 below. Furthermore, DAS fiber optic cables were initially deployed within the wellbore; utilized for well monitoring [26]; and deployed in unconventional reservoirs for hydraulic fracturing monitoring [27], trials of DAS VSP [23], microseismic detection [21], and DAS for the assessment of CO\({}_{2}\) storage [28]. The latest progress of DAS techniques has also been described with respect to ML [29], including a study of the application of ML algorithms in pipeline surveillance systems based on DAS measurement. Further research activity within the scope of ML in the coming years is expected to be applied to DAS data with a robust grounding in the utilization of thorough methodologies. DAS employs a single-laser interrogator unit powered by a single source to investigate data acquired through fiber optic cables. This probing process derives an axial strain-rate profile along the fiber over time, transforming it into an array of numerous seismic sensors with a density spanning only a short distance. Subsequently, an interrogator unit linked to one end of the fiber consistently emits brief laser pulses through the fiber, as depicted in Figure 2. Reflected photons are then subjected to interferometry with the transmitted reference pulse, resulting in a quasi-linear phase shift proportionate to the total strain along the fiber's direction. A laser repeatedly pulses a short distance into the cable; then, an optical interferometry sensor captures the backscattered light and gates that signal into short segments in time, correlating changes in the backscattered light signal at the two-way travel time of light in the fiber to a location in the fiber. Changes from one ping of the fiber to the next are converted into changes in the strain-rate profile [22].