First observations of seismic waves on an active-telecom network using the optical frequency signals of REFIMEVE

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In this seminar I will report on our first observations of seismic events using a coherent optical signal that is propagating in parallel of the data traffic of RENATER, the French national telecommunication network for education and research.
The observations are made with REFIMEVE, that aims at the dissemination of time and frequency signals over RENATER's network, and that compensates for the delay propagation fluctuations for this purpose. It happens so that seismic waves alter the propagation delay by several femto-seconds, that is measurable by our systems.
In this seminar, I will explain first the principle of operation of link stabilization and show examples of observation that can be made when the propagation delays are recorded. I will report on a catalog of tens of non-ambiguous seismic wave events detected by a fiber network for time and frequency metrology, in very good agreement with data recorded by force-balanced broadband seismometers.
I will report on a quantitative analysis of this catalog of events, and show dependency of the sensitivity of the fiber links comprising the network with the location of the event, and show that the position of the center of mass of the detector may vary. Finally I will report on a catalog of detected events built by a machine learning algorithm.