Research Article
Current Situation of Microseismic Monitoring and Vector Scanning
Beiyuan Liang,
Jianli Wang*
Issue:
Volume 13, Issue 3, June 2025
Pages:
39-45
Received:
23 March 2025
Accepted:
27 April 2025
Published:
14 May 2025
Abstract: The current situation of microseismic monitoring at home and abroad is not optimistic. The principles, data acquisition, data processing, and intepretation of many monitoring methods are far from the requirements of microseismic monitoring characteristics, and far from the level of analyzing specific microseismicity. We argue that the main technical reason for this situation is still the lack of understanding of microseismic characteristics and the corresponding monitoring characteristics, so that the development and application of microseismic monitoring are not based on strict seismology, geology, rock mechanics, a large number of reliable experiments, and mathematical statistics. Microseismic monitoring is even more difficult than monitoring stealth aircraft and navigators, in which the target and detector are separated by fluid, and there is always some way to test them. This paper first summarizes the characteristics of microseismic and its monitoring. Based on this, as well as the most basic requirements of seismometry, various monitoring methods are discussed, including their applicable conditions, limitations and development prospects. This discussion shows that the development and application of microseismic monitoring have to be based on the reality of low signal-to-noise ratio, even after avoiding strong noise sources as much as possible during data acquisition and effectively denoising during processing. This paper then reports that in the past two to three years, following the review ("Microseismic and its monitoring") in January 2023, our Vector Scanning (VS) for microseismic ground monitoring has been greatly improved, including an in-depth understanding of the VS principles, the refinement of the conditions necessary for the success of the VS application with a high probability, and their quantitative integration in the VS automated process of data processing and interpretation. A large number of cases are available for mathematical statistics, which provide a basis for analyzing the details of microseismicity. Finally, we describe the specific morphology of the Stimulated Rock Volume (SRV) induced by fracturing, the relationship between the corresponding deformation and the stress fields (equivalent microseismic focal mechanism), and the effect of production measures such as pump shutdown. The necessary conditions, monitoring output patterns, some analyses and questions described here also provide a basis for the test of the microseismic monitoring.
Abstract: The current situation of microseismic monitoring at home and abroad is not optimistic. The principles, data acquisition, data processing, and intepretation of many monitoring methods are far from the requirements of microseismic monitoring characteristics, and far from the level of analyzing specific microseismicity. We argue that the main technica...
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Research Article
Design and Simulation of Dielectric Load Ultra-Wide Band Corrugated Feed for FAST
Jinglong Yu*
,
Hongfei Liu,
Jianbin Li
Issue:
Volume 13, Issue 3, June 2025
Pages:
46-50
Received:
11 March 2025
Accepted:
17 May 2025
Published:
11 June 2025
DOI:
10.11648/j.sd.20251303.12
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Views:
Abstract: Five hundred-meter aperture spherical radio telescope (FAST) is a multi-disciplinary basic research platform that is used for a wide range of astronomy research. Currently, narrow-band multi-beam feed are primarily employed for observation. The development of ultra-wide broadband feed system is beneficial for covering more scientific objectives, while also giving full play to the advantages of the FAST huge reception area in wider frequency band. This paper focuses on the 0.5-3.3GHz feed design, which has better than 10 dB simulated return loss across the bandwidth with the method of using fitting curves and dielectric loading and adding corrugated structures to improve the performance of quad ridge flared horn (QRFH). A centrally positioned PTFE dielectric rod regulates electromagnetic wave phase velocity, enhancing radiation directivity and main lobe symmetry. The dielectric rod is formed by two concentric layers with the same dielectric constant but different structures. The outer layer is evenly slotted to reduce its dielectric constant. The addition of the above technical means ensures the symmetry of the E-plane and H-plane far-field patterns, making the aperture efficiency of the feed relatively balanced over 6.6:1 bandwidth. This kind of feed is designed with an emphasis on performance, ease of tuning and manufacturability compared to the case of multi-layer dielectric rods.
Abstract: Five hundred-meter aperture spherical radio telescope (FAST) is a multi-disciplinary basic research platform that is used for a wide range of astronomy research. Currently, narrow-band multi-beam feed are primarily employed for observation. The development of ultra-wide broadband feed system is beneficial for covering more scientific objectives, wh...
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