Iranian Journal of Geophysics

Iranian Journal of Geophysics

Investigating the Impact of Gauge Length on Distributed Acoustic Sensing (DAS) Data and the Processing: A Case Study in the Nevada Region Using the PoroTomo Array Data

Articles in Press

Document Type : Research Article

Authors
Mona Ali Akbar Khan Afjeh 1
Hosein Hashemi 2
Mohamad Reza Hatami 2
1 Ph.D. Student, Institute of Geophysics, University of Tehran, Tehran, Iran
2 Associate Professor, Institute of Geophysics, University of Tehran, Tehran, Iran
10.30499/ijg.2025.542244.1722
Abstract
In distributed acoustic sensing (DAS) systems, the gauge length parameter plays a crucial role in determining the accuracy and efficiency of recorded data. Gauge length refers to the segment of the optical fiber used for sampling and has a direct impact on the spatial resolution and sensitivity of the recorded signals. Selecting an appropriate gauge length is essential for optimizing the performance of DAS-based seismic monitoring systems. This study investigates the effects of different gauge lengths on the quality of DAS data and the performance of signal processing algorithms. By analyzing data collected from the Brady Hot Springs in Nevada, USA, and comparing the results obtained for various gauge lengths, we aim to explore the challenges and opportunities associated with optimizing this parameter. The findings provide insights into how different gauge lengths influence data clarity, spatial resolution, and overall system performance.
    Our analysis includes gauge lengths of 10, 20 and 30 meter , examined in both the time domain and the frequency domain using Fourier transform. Each of these lengths has distinct implications for the recorded signals. A shorter gauge length typically offers higher spatial resolution but may introduce higher noise levels. In contrast, longer gauge lengths may enhance signal stability but at the cost of reduced spatial resolution. Finding the optimal balance between these trade-offs is key to improving DAS data quality and maximizing its usability in seismic studies. To further refine the recorded data, we apply Wiener deconvolution to the signals corresponding to the selected gauge lengths. This technique helps to mitigate distortions and improve signal clarity, making it easier to extract meaningful seismic information. The effectiveness of this deconvolution process is assessed by evaluating the signal-to-noise ratio (SNR) for each gauge length. The implementation of data processing is carried out using Python-based algorithms, which enable efficient handling and analysis of large datasets. The results obtained through these computational techniques are discussed in detail in the results section, where we compare the impact of different gauge lengths on seismic data interpretation. The ultimate goal is to determine the optimal gauge length that maximizes SNR while preserving spatial accuracy. Our findings indicate that selecting an appropriate gauge length significantly enhances the quality of DAS data and improves the accuracy of seismic event detection. While shorter gauge lengths provide finer spatial resolution; they may require additional noise filtering techniques to ensure reliable data interpretation. On the other hand, longer gauge lengths can improve the overall signal strength but may compromise detailed spatial resolution. The results of this study provide valuable guidelines for designing and implementing high-performance DAS systems tailored to specific seismic monitoring applications. By systematically analyzing the impact of gauge length and employing advanced data processing techniques, this study contributes to the optimization of DAS-based seismic monitoring. The insights gained from this research can assist in refining DAS system configurations to achieve enhanced accuracy and reliability in seismic data acquisition.
 
Keywords
Brady&‌rsquo؛ s hot springs
Distributed Acoustic Sensing
Gauge Length

Subjects

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Iranian Journal of Geophysics

Articles in Press, Accepted Manuscript
Available Online from 26 November 2025