High Performance Optical Seismometer – HIPERSIS

We propose the development and demonstration of an innovative, high resolution, low-cost optical (laser) seismometer aimed at improving the real-time monitoring for regions with high telluric hazard (earthquakes, volcanoes, landslides, tsunmais...), as well as for areas of industrial underground exploration, production and storage (geothermy, oil, gas, deep mines, CO2 and nuclear waste storage,..), for safety as well as production objectives. In the LINES (2009-2012) ANR project, we successfully developed a high resolution optical seismometer prototype on a 3 km long optic cable, based on a 2 Hz commercial geophone and on Fabry-Pérot interferometry. However, further R&D is requested, for entering the industrial market of seismometers, with the ambitious objective of combining miniaturization (<4 cm), resistance to high temperature (250°), average floor noise at less than 2 nanog/sqrt(Hz) in the 1-20 Hz range, omnidirectional (no requested levelling), low cost, and low power. Such an instrument is not yet proposed by the geophysical indutry. This requires new coupled designs in the mechanics, optics, and algorithmics.

HIPERSIS is proposing the Research and Development above, involving two partners of the former LINES ANR project: IPGP, with experts in seismology and seismometry, which will develop the mechanical oscillator and the integration of the optical part; and ESEO, a private engineering school and research institute, with experts of signal processing and electronics, which will design new algorithms and in particular integrate and correct for specificities of the mechanical device (resonance, damping, non linearities). At IPGP, several prototypes will be designed, constructed and tested, aiming at an optical and mechanical amplification of the signal of at least a factor of 5. In particular, the efficiency of a double measurements for common mode rejection will be studied, as well as the sensitivity of the fiber itself to vibration. A first qualification of the integrated sensor will be done in the low-noise underground laboratory of LSBB (Southern France).

Valorization will start after the first year, with the preparation of application projects for microseismic monitoring in the industrial and academic sector, and possibly with the deposition of patents, in coordination with SATTs “idfinnov” and “Ouest valorization” . Concerning the applications, IFREMER will be contacted for testing offshore installations, and geothermal industries will be contacted for testing the sensor in deep, hot boreholes. Also, the results will be presented to industries potentially interested by the instrument for further development and market production.

The 495 ke of ANR contribution are mainly distributed as  about 233 ke of the expenses are related to the development of the mechanical sensor (IPGP and ESEO), and about 262 ke for the personal requested for this development (hired at IPGP ; 50 % permanent at ESEO).