1 Murphy S 2 Klingelhoefer F 2 Barreca G 3 Gaillot 2 A Quetel L 4 Riccobene G 5 Aurnia S 15 Jousset P 6 Poitou C ID: 1019104
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1. Gutscher, M.-A. 1, Royer, J.-Y. 1, Murphy, S. 2, Klingelhoefer, F. 2, Barreca, G. 3, Gaillot2, A., Quetel, L. 4, Riccobene, G. 5, Aurnia, S. 1,5, Jousset, P. 6, Poitou, C. 1, Ciausu, V.2 Intro: Study area, strain cables Bathymetry and micro-bathymetryConnection, cable laying, geodetic networkIntroPreliminary BOTDR and DAS observationsThe orange ‘Home’ Button takes you to the section menuThe left/right arrowstake you to thenext pagePICO NavigationFirst deployment of a 6-km long fiber-optic strain cable and a seafloor geodetic network aross an active submarine fault (offshore Catania, Sicily) the FOCUS experiment1 - LGO Brest; 2 - Ifremer; 3 - Univ. Catania; 4 - IDIL, Lannion; 5 - INFN-LNS Catania; 6 - GFZ, Potsdam
2. Intro: Study areaOffshore Catania: East Sicily / Mt. EtnaFaults and CableRecently discovered strike-slip faultSeafloor observatory (TSS) 3 km from fault New 6-km long fiber optic strain cableCatania (urban region): 1 million inhabitants, devastating historical earthquakes (1908, 1693)
3. Intro: Strain cablesStructural health monitoring of large structures (bridges, dams, pipelines, tunnels, mines, etc.)Laser reflectometryBOTDR (Brillouin Optical Time Domain Reflectometry)50 mm resolution at10’s of km distance Rayleigh
4. Intro: ObjectiveObjective : to monitor an active submarine faultby fiber optics (laser reflectometry)and seafloor geodesyBathymetry, faults, cables and geodetic stations
5. Bathymetry, MicrobathymetryMicro-bathymetry (ROV Victor 6000)Bathymetric map (3-D view)(micro-bathymetry in color)Mt. Etna volcano
6. Bathymetry, MicrobathymetryMicro-bathymetry (w interpretation)Regional bathymetryThin black lines (left) = ship tracks, faults in red, slumps/scarps in green, gulleys/canyons in black
7. Connection, cable-layingShipboard operationsROV Victor 6000 (mapping and seafloor operations)
8. Connection, cable-layingDeep-sea plow (splash)(on board Pourquoi Pas)Y-junction box (hoist)(on board Pourquoi Pas)Shipboard operationsInstrument deployment from vessel
9. Connection, cable-layingCable connected(via cable-end-module to 6km cable)Connection to Y-junction box(using ROV Victor 6000)Seafloor operationsCable connection
10. Connection, cable-layingDeep-sea plow for cable laying(6 km of 9mm diameter fiber-optic cable)Plow and cable-end-moduleSeafloor operationsCable deployment
11. Connection, cable-layingRugged relief (scarp / cliff) and unburied cablePlow track - well buried cable(note small fish at right)Seafloor operationsCable deployment
12. Geodetic networkNetwork of 8 geodetic stations(numbers) and cable track (orange line)Canopus acoustic beacon(splash)Shipboard operationsSeafloor geodetic stations
13. Geodetic NetworkNetwork of 8 geodetic stations(yellow dots) and cable (red line)Canopus acoustic beacon(on the seafloor)Seafloor operationsSeafloor geodetic stations
14. Preliminary BOTDR and DASLaser reflectometry (in LNS Port Laboratory)Three interrogators (2 x BOTDR, 1 DAS)Silixa - DAS (Distributed Acoustic Sensing) (GFZ Potsdam)Febus - BOTDR(IDIL)Viavi - BOTDR(LGO)
15. Preliminary BOTDR and DASNew 6 km-long FOCUS cable (9 mm diameter) (Nexans construction)5 fibers (3 tightly bound in the core + 2 loosely bound in tube)2 optical paths:(6 km + 6 km)(6 km + 6 km + 6 km)with spool boxes at the ends (at the plow and in the cable end module)
16. Preliminary BOTDR and DASLaser ReflectometryBOTDR observationsabsolute baselines16 Oct. (pre-connection)21 Oct. (3 days post-deployment)16 Oct. (connection, cable on reel) loosetighttightloosetighttight29 km existing cable29 km existing cable29 km existing cablestrain: 28 Oct. to 8 Nov. (11 days)loosetighttight29 km existing cable6km6km6kmNew FOCUS cable
17. Preliminary BOTDR and DASLaser reflectometryPreliminary DAS observations19 Oct. 2020, 17:55 (UTC) small earthquake (~M3 about 70km away) (~2 weeks from 6 - 22 October)
18. Preliminary BOTDR and DAS17 October 2020(during plowing operations)Laser reflectometryPreliminary DAS observations29.6 km existing cable33.6 km plowing operations38.0 km plowing operations35.8 km reel and loop back(4 km of cable deployed, 2.2 km still on reel)
19. Preliminary BOTDR and DAS21 October, 2020 (3 days after cable deployment)Laser reflectometryPreliminary DAS observations29.6 km existing cablecable oscillations 135.8 km reel and loop backcable oscillations 2cable oscillations 2cable oscillations 1 (lost in the noise)