Within the framework of the EU funded FOCUS project, we have established BOTDR (Brillouin Optical Time Domain Reflectometry) time series spanning up to 3 years on academic and commercial fiber-optic cables. Offshore Catania a 6-km-long dedicated fiber-optic cable (connected to a 29-km-long electro-optical cable), recorded natural and man-made strain signals of 40 - 250 microstrain at the seafloor (in 1800 - 2000 m water depths). The strongest natural signal (40 microstrain elongation) developed from 19 - 21 Nov. 2020, where the cable crosses a mapped submarine fault in the first of 4 locations. However, a network of 8 seafloor geodetic stations (acoustic beacons mounted on tripods) recorded no baseline changes, thus ruling out a tectonic movement. A simultaneous positive-negative strain doublet (+40 to -20 microstrain) observed 6 km from shore (in 300 m water depth), suggests a downslope current affected the shallow and deep portions of the fiber-optic cable path length. The 6-km long FOCUS cable includes a redundant, triple-loop, consisting of 1 loose and 2 tight optical fibers. (A second double-loop, consisting of 1 tight and 1 loose fiber is being monitored by a second BOTDR interrogator.) The tightly bound fibers typically record a strain signal twice as high as the loose fibers (40 vs 20 microstrain for the natural signal). Weight bag drops created man-made signals along four 120-m-long segments, with amplitudes of 80 - 250 microstrain (in the tight fibers), which gradually decay in the following months / years.

Baseline measurements were repeatedly taken on the 100-km-long Capo Passero (SE Sicily) electro-optical cable in Oct. 2022, March 2023, and Nov. 2023. The main purpose of the monitoring is to test the maximum range attainable with commercially available BOTDR interrogators. While no significant strain development has been measured on the optical path, we report that with an acquisition time of 2+ hours it is possible to extend the measurement range up to 80 km. This represents a benchmark for future BOTDR measurements over long distances.

In June 2022, in collaboration with the “Conseil Regional” of Guadeloupe and Orange, we began long-term monitoring of a network of unrepeated submarine telecom cables that links the islands of the Guadeloupe archipelago. We repeated the measurements of the same fiber segments (30 - 70 km length), in Dec. 2022, June 2023, Nov/ Dec. 2023, and finally May 2024 in order to identify strain or thermal signals along the cable during the 2-year period. We confirm that using the BOTDR technique, we detect significant shifts in the Brillouin frequency (2 - 5 MHz), which could represent substantial strain signals  (40 - 100 micro-strain in amplitude) in several locations along the cable network. These signals, which can be positive (elongation) or negative (shortening) occur typically in areas of steep seafloor slopes (e.g. the shelf break) or in submarine valleys/canyons. Our preliminary interpretation is that stretching and shortening of the cable (representing about 1 cm over a few hundred meters) is occurring, most likely due to sea-bottom currents. 

How to cite: Gutscher, M.-A., Quetel, L., Cappelli, G., Riccobene, G., Aurnia, S., Nativelle, C., Philippon, M., and Lebrun, J.-F.: Observing seafloor processes by distributed Fiber Optic Sensing: examples from academic cables offshore East Sicily (Italy) and a commercial telecom network in the Guadeloupe archipelago (Lesser Antilles)., Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-58, https://doi.org/10.5194/egusphere-gc12-fibreoptic-58, 2024.

Active seismic experiments during the Apollo missions characterized the lunar regolith and crust, while passive monitoring suggested a thermal stress origin for the high-frequency lunar seismic noise. Deploying Distributed Acoustic Sensing (DAS) instruments, capable of withstanding the extreme lunar conditions, would allow to examine various lunar environments including permanently shadowed regions, which trap water ice due to their extremely cold temperatures. Benefiting from high spatial and temporal resolutions, DAS surveys would allow analyzing wave propagation, constructing 2D wave velocity sections, and potentially identifying ice-related velocity variations. How the DAS technology positions in terms of self-noise with respect to Apollo and modern sensors? We estimate the strain noise level of geophones to be around 1 pε/sqrt(Hz). For a 5-km long optic fiber with 10 meters gauge length, the typical self-noise of current DAS systems is around 1 pε/sqrt(Hz). This indicates that DAS instruments may achieve a low noise level on par with the best current geophysical technologies, which is crucial for precise and reliable exploration of lunar structure. We will discuss experiments that would be necessary for qualifying such an instrument for space applications.

How to cite: Tauzin, B., Lognonné, P., Kawamura, T., Panning, M., Jousset, P., Lanticq, V., Mercerat, D., Metaxian, J.-P., Hibert, C., De Raucourt, S., Coutant, O., and Almoric, E.: DAS system for the Moon, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-47, https://doi.org/10.5194/egusphere-gc12-fibreoptic-47, 2024.

Optical fiber sensors constitute the biggest revolution in geophysical and environmental sensor technology since digitization.  Although traditional sensors have been refined through decades of incremental progress, optical fiber sensors provide an entirely new lens with which to study fundamental processes. These sensors are particularly advantageous for systems that require high spatial and temporal resolution (i.e., on the order of 1-10m spatial scale and 100 s to 100 kHz sampling rate).  The UW Fiber Lab has deployed these technologies in Antarctica, Greenland, Alaska, New Zealand, and at a dozen sites in Europe and the lower United States.  The main focus of this research has been on studying Earth's cryosphere, submarine, urban, and otherwise difficult-to-instrument environments. This talk will focus specifically on use cases where basic knowledge has been gained regarding the calving front of large, ocean-terminating glaciers in Greenland, paleoclimatic history of the Antarctic ice sheet, monitoring of clean energy systems, and earthquake detection and ground motion hazard characterization.  The presentation will conclude with a forward looking discussion regarding the rapid pace of development of basic optical physics and engineering, and the prospects for future growth at the intersection of optical fiber sensor technology and basic geoscience research.

How to cite: Lipovsky, B., Abadi, S., Denolle, M., Gaete Elgueta, V., Gräff, D., Manos, J.-M., Ni, Y., Shi, Q., Sprinkle, P., Wilcock, W., and Williams, E.: New Earth and Planetary Science Discoveries Enabled by the Optical Fiber Sensing Revolution, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-95, https://doi.org/10.5194/egusphere-gc12-fibreoptic-95, 2024.

I present the results of the Suboptic working group formed during the Suboptic 2023 conference to create a synergy between submarine cable owners and government institutions to improve safety for coastal communities. 

Since discovery of sensing capabilities of operational submarine cables, a perfect storm of smart optical spectroscopic techniques enabled enhancement of cable security and environmental protection. We are looking for synergy between cable owners and government institutions to improve safety for coastal communities. In high seas, Subsea Environmental Sensing with Operational Submarine Cables (SESOSC) has a target to create industry wide collaboration to enable early warning of tsunami. As awareness of the importance and complexity of the ocean environment becomes increasingly clear, the need for improved sensing, with better spatial resolution and increased temporal coverage, is now pressing. Submarine cables developed to transmit information between continents can be used as sensors. Sensing with submarine cables was a topic of active discussion at the SubOptic 2023 Conference, where two dozen authors presented results convincing that sensing is a powerful tool to improve cable safety but also provides opportunities for environmental monitoring.  Enormous opportunities of sensing with submarine cables are clear to many today, and need to be addressed from juridical and security perspectives. Fiber optic networks, both terrestrial and subsea, are a growing part of the information revolution. It is clear that sensing with telecom optical fibers creates a base for multiple applications, including earthquake and tsunami early warning. We discuss the next step for the submarine industry to improve cable safety and enhance environmental monitoring worldwide.

This paper contains a summary of Working Group results dedicated to DAS technology for coastal areas cable safety and environmental surveillance and sensing with trans-continental operational cables.  We discuss the strategy to facilitate applications of operational submarine cables for sensing of earthquakes, water waves, and improvement of security of submarine cables. We also plan to provide a consolidated industry viewpoint on the considerations and opportunities afforded by existing and emerging cable-based technologies for sensing the marine environment. The Working Group envisions international cooperation between cable owners and government agencies to provide low frequency data to tsunami warning centers with an early alarm threshold established based on the research project. We are working on the development of the platform  to summarize industry position on the technologies in the field of submarine cable-based environmental sensing. The Working Group does not cover the SMART submarine cables program as the Working Group deals with fiber as a sensor technologies that do not require modification of the wetplant. Optical transmission fibers are excellent sensors and operational submarine cables can provide additional value to submarine cable owners.

How to cite: Kamalov, V.: Subsea Environmental Sensing with Operational Submarine Cables, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-19, https://doi.org/10.5194/egusphere-gc12-fibreoptic-19, 2024.

Geothermal reservoirs require reliable well-completion techniques to reach well integrity. Well, integrity means there are no flow paths behind the casing at all. While constructing the well, the drilling mud must be fully displaced by uncontaminated cement, measured in displacement efficiency. Conventional real-time measurements show average pumping parameters to control the cement job's success. However, studies show issues with well integrity worldwide. We aim to improve well integrity by closing an information gap within the construction phase using continuous distributed fiber-optic sensing with dense spatial sampling.

This study investigated the primary cementing of an 874 m surface casing in Munich, Germany. A fiber optic cable deployed behind the casing enabled the measurement of distributed dynamic strain rate (DDSS or DAS) and distributed temperature (DTS) during cement placement. We used field data from the cementing service, developed a fluid displacement model, and compared the results with those of the fiber optics.

While we can trace only the rise of a cold front in the temperature data, the combined interpretation of DAS data shows features that allow comprehensive insights into the subsurface displacement process. We observed two rising velocities at a constant pumping rate. We were able to correlate them to the rise of different fluid interfaces. We conclude that the freshwater spacer does not displace the drilling mud but the first arrival of cement. Once the breakouts are filled, the succeeding cement seeks the path of least resistance without displacing cement in the breakouts again.

Our findings suggest the possibility of tracking the rise of different fluids and the stability of their interfaces in real-time with distributed dynamic strain sensing. Having sensors along the borehole to track the displacement efficiency enables on-site reactions to ensure the cement jobs' success.

How to cite: Hart, J., Polat, B., Schölderle, F., Ledig, T., Lipus, M., Wollin, C., Reinsch, T., and Krawczyk, C.: Closing an Information Gap in Geothermal Well Construction: Continuous Distributed Fiber-Optic Sensing for Improved Displacement Efficiency, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-22, https://doi.org/10.5194/egusphere-gc12-fibreoptic-22, 2024.

We present the results and current challenges of an experiment with Distributed Acoustic Sensing (DAS) on Grímsvötn volcano in Iceland, and its potential for improvements in source characterization using Full-Waveform Inversion (FWI).

We deployed a 12 km long fibre-optic cable for one month (May 2021) on Grímsvötn, Iceland’s most active volcano on a centennial time scale, which is covered by the Vatnajökull ice cap. The cable was trenched 50 cm into the ice, following the caldera rim and ending near the central point of the caldera on top of a subglacial lake.

We discover previously undetected levels of microseismicity, and we locate these events with first-arrival times and a probabilistic inversion using the Hamiltonian Monte Carlo algorithm. The ~2000 detected events have local magnitudes between -3.4 and 1.7, and their locations indicate clear clusters of activity. These appear near surface expressions of the caldera fault, such as fumaroles, and cauldrons. We use the results, combined with an initial velocity model, to set up an FWI workflow, that takes the complex topography and subsurface into account. We create the initial velocity model for the firn-ice transition by inverting a dispersion curve of the snow cat driving along the cable, and we combine this with homogeneous media for the bedrock, ice layer, and subglacial lake. We perform an initial forward modelling study for a selection of ~600 events in the frequency range of 1.5 – 3 Hz, combined with a least-squares inversion to obtain the moment tensor components of each event. Finally, we assess the resulting moment tensors and their resolution matrix in order to evaluate the potential to invert for source characteristics.

This research shows the results and potential of DAS on active subglacial volcanoes, and we hope that this research will contribute to the fields of volcano monitoring and DAS modelling.

How to cite: Klaasen, S., Noe, S., Thrastarson, S., Cubuk-Sabuncu, Y., Jónsdóttir, K., and Fichtner, A.: Moment Tensor inversion with Full-Waveform Inversion and Distributed Acoustic Sensing on a subglacial volcano: Grímsvötn, Iceland., Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-25, https://doi.org/10.5194/egusphere-gc12-fibreoptic-25, 2024.

Scientific infrastructures cover areas worldwide to monitor Earth system processes.  Most of these are installed on land, but land masses make up only about 30% of the Earth's surface.  The oceans and particularly the ocean floor are difficult to access, and thus are not adequately instrumented and monitored.  Since they play a critical role in regulating climate as a heat and carbon store, and are the site of deadly natural disasters including strong earthquakes, tsunamis, and volcanic eruptions, we are faced with a substantial gap in the monitoring of critical physical parameters in the near-coast and offshore domains.  For seismology and geohazard assessment the global coverage is as essential as for oceanography and climate studies.  Using a combination of established and novel technologies implemented in telecommunication infrastructure on the sea-floor and coastal areas will, without a doubt, prove to be a game changer in geosciences and Earth system understanding.

In recent years, three different and complementary fiber-optics-based technologies have gained at-tention as valuable tools for investigating Earth system processes: Distributed Fiber-Optic Sensing (DFOS), State of Polarization (SoP), and Science Monitoring and Reliable Telecommunications (SMART) cable systems. The first two technologies use the fiber-optic cable as the sensing element, while in the third technology type (SMART cable systems), independent sensors are integrated into fiber-optic cable repeaters, and the cable is used for power and data transmission. These technologies and their application to geoscientific problems are at different levels of maturity, and combining them with a FAIR data infrastructure into a demonstrator is the vision of the planned infrastructure project SAFAtor (see presentation by Cotton et al., this meeting).

We want to present and discuss in the framework of our planned SAFAtor initiative (SMART Cables And Fiber-optic Sensing Amphibious Demonstrator) the first experiments we performed in the testbeds foreseen at Mt. Etna, in the Marmara Sea, and in Chile.  While Etna’s volcano-tectonic setting is complex (Jousset et al., Currenti et al.) and origin and spatial-temporal evolution of the volcanism and its relationship with the tectonic dynamics are still a matter of debate, its unstable eastern flank stretches far into the Ionian Sea with an average flank movement of 2-3 cm/yr.  In the Marmara Sea, critical data on offshore fault structure and seismicity will enable efficient investigation of structure and seismic hazard underneath densely populated areas along the coast, especially in Istanbul where the major earthquake is overdue.  This also holds for Chile, where ongoing subduction erosion and mature seismic gaps should be complemented by new monitoring efforts.  Developing our SAFAtor activities in terms of adapted fibre-optics sensing and monitoring will thus help areas exposed to hazard at active plate boundaries and volcanic systems in coastal zones.

How to cite: Krawczyk, C., Cotton, F., Tilmann, F., Wallace, L., and Team, S.: Closing the Ocean Data Gap: near-coast fibre-optics sensing to monitor tectonic and volcanic events, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-41, https://doi.org/10.5194/egusphere-gc12-fibreoptic-41, 2024.

The INFN-LNS (Istituto Nazionale di Fisica Nucleare – Laboratori Nazionali del Sud) operates two deep-sea cabled infrastructures in Eastern Sicily.

The first infrastructure connects a shore laboratory in the port of Catania to two underwater sites in the Gulf of Catania. This connection is made through an electro-optical submarine cable, approximately 25 km long, which hosts 10 optical fibers. At a distance of 20 km from the shore laboratory, the cable splits into two branches via a Y-junction to reach two different cable termination frames: TSN (Test Site North) and TSS (Test Site South), both located at a depth of 2100 m.

The second infrastructure is situated 100 km southeast of Portopalo di Capo Passero at a depth of 3500m. The underwater site is connected to the shore laboratory in the harbor of Portopalo via two underwater electro-optical cables. These cables carry 20 and 48 optical fibers, respectively. The second cable, funded by the IDMAR PO-FESR project, was deployed between November 2020 and November 2022. Thanks to a Y-branching unit, the cable is split underwater into two different branches.

These two LNS fiber optic infrastructures have hosted several Italian and European projects, including Geoinquire, EMSO-ERIC, IPANEMA/ECCSEL-ERIC, and FOCUS-ERC in Catania; KM3NeT and EMSO in Portopalo di Capo Passero.

Specifically, within the FOCUS-ERC and Geoinquire projects, DAS (Distributed Acoustic Sensing) and BOTDR (Brillouin Optical Time Domain Reflectometer) measurements were acquired over a long period.

The optical network of the two deep-sea infrastructures and the available assets for geoscience will be described.

How to cite: Pulvirenti, S. and Viola, S.: The INFN-LNS Fibre optic infrastructure, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-10, https://doi.org/10.5194/egusphere-gc12-fibreoptic-10, 2024.

Distributed Acoustic Sensing (DAS) technology is a new photonic method that can convert several tens of kilometer-long seafloor fiber-optic telecommunication cables into dense arrays of strain sensors. With such spatial and temporal resolution, DAS appears as a potential future alternative to in-situ oceanographic measurements. Nevertheless, the DAS measurement needs to be calibrated because several factors can induce modifications to the measurements such as the structure of the cable or the level of burial in the sediments. In addition, the mechanisms through which the external stresses are conveyed to the fiber are still not well understood. An initial strategy involves analyzing the response of the DAS data to surface gravity waves as these are continuously present and well-characterized signals, that can be readily measured at shallow depth. From December 2020 to January 2021, an in-situ campaign was performed which involved deploying a pressure sensor at a depth of 15 meters for nearly 2 months next to the 50 km-long LSPM (Laboratoire Sous-marin Provence Méditerranée) seafloor cable in the bay of Les Sablettes, South of France. In the frequency band of surface gravity waves, we identify a remarkable linear correlation between the energy of the pressure sensor and that of the colocated DAS sensor, for various sea conditions. This result implies that the significant wave height can be reconstructed from DAS data at all points along the telecom cable, from the coast down to the cut-off depth of linear wave theory (roughly 100 meters in that region). From the linear wave potential theory, we derive an analytical transfer function linking the cable deformation and wave kinematic parameters. Even though this transfer function provides a first quantification of the effects related to waves and the cable response, it does not allow to distinguish between the different components of the wave spectrum (long-period, infragravity, surface gravity, ultra-gravity waves...), nor acknowledge the potential contribution of temperature variations. Also, the coupling processes between water, cable, and sediment remain to be included in this transfer function. In 2023, along the same telecom cable, we deployed 6 instrumented stations along the LSPM cable for 3 months. In particular, we installed instruments to measure seafloor pressure and temperature, the velocity components in the water column, as well as variations in the depth of sediments relative to a reference. These measurements will enable us to refine the analysis of the processes involved in the DAS response. 

How to cite: Mohammedi, A., Sladen, A., Meulé, S., Pelaez-Quiñones, J., Bouchette, F., Ponte, A., and Ampuero, J.-P.: Reconstruction of nearshore surface gravity waves from Distributed Acoustic Sensing data, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-79, https://doi.org/10.5194/egusphere-gc12-fibreoptic-79, 2024.

Distributed Acoustic Sensing (DAS) offers unprecedented meter-scale spatial sampling of strain/strain-rate wavefields, enabling unaliased seismic event observations. DAS technology utilizes fiber optic cables (FOCs), extending seismological observations to extreme environments, including ocean floors. Given the logistical difficulties in deploying and maintaining traditional seismic stations in these contexts, seismological data near oceanic earthquake sources remain limited. On a positive note, telecommunication FOCs are often deployed on the ocean bottoms to connect urban areas on land, potentially bridging this observational gap.

Traditional seismological monitoring, which aims to locate earthquake sources, typically relies on phase picking and subsequent data inversion. In a standard seismometer network, automatically-retrieved arrival times can be manually validated by expert operators; however, this task becomes practically impossible with DAS due to the unprecedented data density it offers, which can easily reach tens of thousands channels, considering the current capabilities of interrogating cables up to 100 km. For the purpose of leveraging both data measurements close to the source (DAS) and the improved azimuthal coverage by land stations, DAS data flows must be automated. Potential solutions include accurately tuning automatic pickers for the specific FOC and/or employing data selection and weighing procedures. Recently, pickers based on machine learning have been tested for DAS as substitutes for standard pickers, offering promising results and efficient arrival time measurements. Despite these advancements, challenges persist in accurately estimating onsets due to spatial variability in DAS waveforms, arising from a) uniaxial signal polarization, b) sensitivity to site conditions, and c) heterogeneities in FOC coupling. These data uncertainties, in turn, affect event location accuracy.

We address this problem by conducting a preliminary comparison of two standard pickers (based on the actual amplitude-frequency content of each channel) with a machine-learning-derived picker. We focus on DAS recordings of six local earthquakes located on the ocean bottom between Fuerteventura and Gran Canaria islands during an experiment from November 2022 to April 2023. Each earthquake is provided with a reference location from the regional network of seismometers. Kurtosis and FilterPicker (standard pickers) and Phasenet-DAS (machine-learning picker) onsets are inverted for event location, with a focus on statistically comparing the solutions' uncertainty (scattering). To achieve this, we employed a Markov chain Monte Carlo method to estimate the Posterior Probability Densities (PPDs) of hypocentral parameters.

In a second stage, we test a data-weighing approach on absolute arrival times based on specific channel properties. The aim is to assess its effects on location PPDs, in comparison to the “not-weighed” inversion. We repurpose the same algorithm, previously used for the location comparison, to modify each entry of the covariance matrix in the Bayesian inversion scheme, thus enabling a differential weighting of the arrival times. These preliminary comparisons of the efficiency of automatic pickers and data weighting procedures are commonly employed for the evaluation of standard seismological networks. With DAS arrays, these approaches become even more crucial, given the reduced space for manual validation by experts.

How to cite: Bozzi, E., Piana Agostinetti, N., Ugalde, A., Latorre, H., Cubas Armas, M., Ventosa, S., Villaseñor, A., and Saccorotti, G.: Comparing location uncertainties with automatic pickers on DAS data: case studies from Canary Islands, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-17, https://doi.org/10.5194/egusphere-gc12-fibreoptic-17, 2024.

The IPANEMA project, funded under the ECCSEL-ERIC activity, aims at studying the natural emissions of carbon dioxide in the Mediterranean region via acoustic detection. In the framework of IPANEMA INFN-LNS has designed two underwater stations equipped with hydrophones and CO2 sensors: a shallow water (20 m depth) autonomous and retrievable observatory, deployed offshore the Island of Panarea (Aeolian Islands, Tyrrhenian Sea) and a cabled deep sea observatory, to be deployed in offshore the Coast of Catania at 2000 m depth (Sicily, Western Ionian Sea). Both detectors are capable to monitor the sea soundscape from a few Hz to just under 100 kHz.

In this context, INFN is investigating the possibility to use Distributed Optical Fiber sensing (DOFS) to enable the measurement of biological and anthropogenic acoustic signals along the entire length of underwater electro-optical cables. Unlike conventional sensors that measure at specific points, DOFS systems provide distributed measurements along the fiber length with high spatial sampling, allowing for dense monitoring of large structures or environments in real time. In this work, we will focus on the application of DOFS in the monitoring of biological sounds emitted by fin whales, as demonstrated by recent researches in Isfjorden Sea, Norway.

During a campaign of measurements between November 9th and 16th, 2023, IFREMER interrogated with an ASN OptoDAS two seafloor electro-optical cables of the INFN-LNS marine infrastructure in Eastern Sicily. The Distributed Acoustic Sensor (DAS) system was first connected to the LNS-INFN electro-optical cable, extending 25 km from the port of Catania to its end at approximately 2100 m water depth. Another set of measurements was carried out at the LNS-INFN Capo Passero site, using a cable extending 100 km to the shore, reaching depths of around 3500 m. In this area a research study conducted by INFN-LNS between 2012 and 2013, using hydrophones on seafloor showed the presence of fin whales.

In this work we will present the analysis of DAS signals: custom codes for data reduction, noise filtering and search for the typical fin whale calls (20 Hz intermittent pulses) will be presented and results discussed.

How to cite: Idrissi, A., Aurnia, S., Di Mauro, L. S., Pulvirenti, S., Riccobene, G., Diego-Tortosa, D., Viola, S., Sanfilippo, S., Bonanno, D., Le Pape, F., Ker, S., Murphy, S., Cappelli, G., Quetel, L., and Gutscher, M.-A.: Search for fin whale calls and shipping noise in Western Ionian Sea using Distributed Acoustic Sensor, Galileo conference: Fibre Optic Sensing in Geosciences, Catania, Italy, 16–20 Jun 2024, GC12-FibreOptic-85, https://doi.org/10.5194/egusphere-gc12-fibreoptic-85, 2024.