9:30 AM - 9:45 AM
[STT35-03] Extending the Range of Fiber-optic DAS Systems For Seismicity Monitoring
Keywords:Distributed Fiber-optic Sensing, seismicity, earthquake, land-based
Recent years show increased use of fiber-optic distributed strain sensing based on Rayleigh scattering for earthquake and induced seismicity measurements. For earthquake monitoring and early-warning often existing fiber-optic cable is used that happens to be installed on existing infrastructure for data transmission purposes. While the sensitivity is lower than compared to purpose-installed dedicate fiber installation, the cost savings are large. Deploying tens of thousands of sensor with the installation of a DAS system at a fiber network location allows to create large-N sensor networks that can enhance sensitivity through beam-forming and other processing techniques.
Typical ranges of current DAS systems have been limited to 30-50km. However, for practical purposes we would like to have larger sensor array lengths with fine sensor spacing, so that we can adapt the sensing geometry to specific detection, warning and scientific measurement purposes. Range-extending DAS technology is an active field of research and applications with circulators or amplifiers have been proposed and being tested. While these are certainly applicable to solve specific range problems, we focus on improving the range an unmodified fiber-optic cable installation. This allows us measure without modification to the installed infrastructure.
In an effort to prove long-range DAS sensing, we acquired seismicity data with a DAS system on an internet data cable on land. We demonstrated that this long-range DAS system is capable of supporting a long and dense sensing array to 100km with a channel spacing of 10m. We show examples of small local and regional earthquakes that were recorded and detected on this ad-hoc 100km sensing array.
Typical ranges of current DAS systems have been limited to 30-50km. However, for practical purposes we would like to have larger sensor array lengths with fine sensor spacing, so that we can adapt the sensing geometry to specific detection, warning and scientific measurement purposes. Range-extending DAS technology is an active field of research and applications with circulators or amplifiers have been proposed and being tested. While these are certainly applicable to solve specific range problems, we focus on improving the range an unmodified fiber-optic cable installation. This allows us measure without modification to the installed infrastructure.
In an effort to prove long-range DAS sensing, we acquired seismicity data with a DAS system on an internet data cable on land. We demonstrated that this long-range DAS system is capable of supporting a long and dense sensing array to 100km with a channel spacing of 10m. We show examples of small local and regional earthquakes that were recorded and detected on this ad-hoc 100km sensing array.