To date, the infrasound community has avoided deployments in noisy urban sites because interests have been in monitoring distant sources with low noise sites. As monitoring interests expand to include low-energy urban sources only detectable close to the source, case studies are needed to demonstrate the challenges and benefits of urban infrasound monitoring. This case study highlights one approach to overcoming urban challenges and identifies a signal's source in a complex acoustic field. One 38 m and one 120 m aperture infrasound arrays were deployed on building rooftops north of downtown Dallas, Texas. Structural signals in the recorded data were identified, and the backazimuth to the source determined with frequency-wavenumber analysis. Fourteen days of data were analyzed to produce 314 coherent continuous-wave packets, with 246 of these detections associated with a narrow range of backazimuth directions. Analyzing the backazimuths from the two arrays identified the Mockingbird Bridge as the probable source which was the verified with seismic measurement on the structure. Techniques described here overcame the constraints imposed by urban environments and provide a basis to monitor infrastructure and its conditions at local distances (0-100 km).
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http://dx.doi.org/10.1121/1.5081714 | DOI Listing |
Sensors (Basel)
October 2024
Infrasound Laboratory, Hawai'i Institute of Geophysics and Planetology, School of Ocean and Earth Science and Technology, University of Hawai'i at Mānoa, Kailua-Kona, HI 96740, USA.
Explosion monitoring is performed by infrasound and seismoacoustic sensor networks that are distributed globally, regionally, and locally. However, these networks are unevenly and sparsely distributed, especially at the local scale, as maintaining and deploying networks is costly. With increasing interest in smaller-yield explosions, the need for more dense networks has increased.
View Article and Find Full Text PDFSensors (Basel)
June 2024
School of Electronics Information and Electrical Engineering, Yangtze University, Jingzhou 434023, China.
Dynamic liquid level monitoring and measurement in oil wells is essential in ensuring the safe and efficient operation of oil extraction machinery and formulating rational extraction policies that enhance the productivity of oilfields. This paper presents an intelligent infrasound-based measurement method for oil wells' dynamic liquid levels; it is designed to address the challenges of conventional measurement methods, including high costs, low precision, low robustness and inadequate real-time performance. Firstly, a novel noise reduction algorithm is introduced to effectively mitigate both periodic and stochastic noise, thereby significantly improving the accuracy of dynamic liquid level detection.
View Article and Find Full Text PDFSci Rep
May 2024
International Data Centre, Comprehensive Nuclear-Test-Ban Treaty Organization, PO Box 1200, 1400, Vienna, Austria.
The International Monitoring System (IMS), installed and maintained by the Comprehensive Nuclear-Test-Ban Treaty Organization (CTBTO) with the support of States Signatories, is a global system of monitoring stations based on four complementary technologies: seismic, hydroacoustic, infrasound and radionuclide. One of the IMS radionuclide stations is located in Spitzbergen, the largest island of the Norwegian Svalbard Archipelago, which borders the Barents Sea and the Northern Atlantic Ocean. It has been demonstrated that signs of climate change are particularly noticeable in that region.
View Article and Find Full Text PDFJ Acoust Soc Am
March 2024
Bundesanstalt für Geowissenschaften und Rohstoffe, B4.3, Hanover, Germany.
The International Monitoring System (IMS) has been established as part of the Comprehensive Nuclear-Test-Ban Treaty to monitor nuclear testing and is comprised of infrasound, hydroacoustic, seismic, and radionuclide stations; it is also used more widely by the scientific community for scientific and civilian applications. For the infrasound stations, on-site calibration provides an accurate measure of the sensor (microbarometer + wind-noise reduction system) frequency response, used to monitor that the sensor response remains within tolerance of the baseline established when the station is certified. However, this on-site calibration can also be used when there are issues/defects with the sensors.
View Article and Find Full Text PDFOn March 5, 2022, a 12 kg meteoroid crossed the sky above Central Italy and was observed by three different observational systems: the PRISMA all-sky camera network (10 stations), the Italian national seismic network (61 stations), and a 4-element infrasound array. The corresponding datasets, each with its own resolution, provided three independent assessments of the trajectory, size and speed of the meteoroid. The bolide traveled across central Italy with an azimuth of 102 degrees, becoming visible at about 91 km above sea level with a velocity of about 15.
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