Buoyed by successful deployments on long offshore cables with our 50km QuantX Interrogator Unit in early 2020, realizing there was still useful signal beyond 50km, OptaSense set out to push these ranges further and in late 2020 deployed a 100km monitoring mode to one of our assets in the Eastern Sierra region of California.
Deployed on a 100km / 20dB cumulative loss fiber, we were able to instrument a massive stretch of ground on a commercial internet dark fiber. Monitoring both high-frequency acoustic/strain data (thanks to the true Nyquist frequency range accessible on QuantX) as well as low -frequency seismic data, OptaSense demonstrated that high-quality phase and amplitude data could be continuously retrieved and harvested during extended periods over the entire measurement range.
OptaSense Head of Innovation, Martin Karrenbach, reports that “The extended-range QuantX system really helps with our understanding of the seismic wave field recording by allowing significantly more data to be harvested from a single system with a coherent baseline, thus making the job of maintenance, analysis and information extraction that much easier.” Initial results from the system were presented at the April Seismological Society of America meeting.
The 100km mode will be available in all future QuantX systems from early summer 2021 and can be retrofitted to existing units without hardware modification.
Magnitude 2.6 earthquake at ~90km offset from array visible over entire monitoring range, showing P (top) and S waves clearly.