De Caro, Mariagrazia. (2019). Gravimeter dataset (IFSI (INAF) Prototype #2 @ 1 Hz) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

A prototype of gravity meter built at the Istituto di Fisica dello Spazio Interplanetario (IFSI) of the National Institute of Astro-Physics (INAF) was installed on the GEOSTAR deep-sea multidisciplinary observatory in the Gulf of Cadiz (Portugal). The dataset contains relative values of gravity acceleration measured with sensitivity close to 10^-9 g/sqrt(Hz) in the range from 10^-5 to about 1 Hz. The instrument performs measurements of the Earth gravity acceleration due to low ground movements (tides) and fast ground movements (seismic wave propagation)

De Santis, Angelo. (2019). Vector Magnetometer dataset (Fluxgate #1 @ 1 sample / 4 sec) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

This sensor provides the three components of the magnetic induction vector in the directions N-S, E-W and Z (vertical). It is a fluxgate prototype developed at INGV laboratories equipped with an inertial platform for levelling control. It provides continuous seafloor magnetic data which are important for two main reasons: a) they extend the magnetic observations from land to the seafloor, improving the spatial distribution in the Italian territory; b) these data are important for the study of short and long magnetic field time variations. The variational data allow us to estimate the resistivity structure underneath the area of observations and possibly to detect some magnetic variations related to some geo-hazards, such as earthquakes and tsunamis. The main aim is the continuous and almost real-time measurement of the three components of the Earth?s magnetic field in a very peculiar environment which in fact has a favorable impact on the quality of the measurements: first, the temperature is more stable at the sea bottom, especially in deep sea sites, so the instrumental drift due to temperature variations is absent or negligible. Second, the water column acts as a natural "shield" to the highest frequencies of the iono- and magnetosphere inducing fields

Giovanetti, Gabriele. (2019). DACS dataset (SMO NEMO-SN1 DACS @ 1 Hz) from /NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

The Data Acquisition and Control System is the set of hardware used to acquire and transfer to shore scientific data. It provides power to all the underwater instrumentation. The data generated by DACS are used to monitor the operativity of the system, in order to signal possible malfunctioning, and ease to find their reasons. In the data can be also found information about the status of the platform, that can be useful for scientific data users (i.e. heading and tilt). Data are used mostly for engineering tasks, thus their precision and quality is not a relevant issue

Monna, Stephen. (2019). Seismometer dataset (Guralp CMG-1T @ 100 Hz) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

This digital database comprises seismological data recorded during the SMO project by a 3 component broadband seismometer. The sensor was installed on the the NEMO-SN1 (Neutrino Mediterranean Observatory - Submarine Network 1) seafloor observatory, offshore of the Eastern coast of Sicily (Southern Italy) at a depth of 2036 m. The seismometer is installed in a dedicated vessel integrated in a separate structure connected to the observatory via a special mechanical release. To guarantee a good coupling with the sea bottom, the structure is disconnected just after the observatory touch-down and kept linked to the frame by a slack rope (Favali et al., 2006). The sensor is connected to a 24 bit digitizer on the observatory. The GPS signal is transmitted underwater to the digitizer, so that the data packages are time-stamped locally. This project is a continuation of GNDT 1, GNDT 2 and SMO 1 where the main objective was to establish a multiparameter seafloor observatory off-shore eastern Sicily. One of the main aspects of SN1 2019 remains long-term geophysical monitoring and broad-band seismic measurements from this site is of great interest given its proximity to the Etna volcano (~ 50 km) and to offshore seismogenic structures where some of the most destructive earthquakes in Italy took place (some of them generated tsunamis). For this reason a tsunami detection systems is implemented on-board the observatory and the seismometer is an important component

De Santis, Angelo. (2019). Scalar Magnetometer dataset (Marine Magnetics Sentinel (3000 m) @ 1 sample / hour) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

This sensor is used to measure the total intensity of the magnetic induction vector. The model used is an Overhauser proton magnetometer supplied by GEM. Associated with the SMO 1 - Vector Magnetometer on-board SN1, the Overhauser proton magnetometer completes the magnetic measurement system ensuring reliability of vector data. The main aim of this scalar sensor is the calibration of SMO 1 - Vector Magnetometer data

Chierici, Francesco. (2019). Pressure gauge dataset (Paroscientific 8CB-4000-I @ 1 sample / 15 sec) from INAF/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

This sensor measures the hydrostatic (water column) pressure exerted on the sensor resulting from the pressure of water above its position and the atmospheric air pressure acting on the sea surface. Whether it is not possible to use a vented reference to equalise the offset due to atmospheric pressure, the true water level is obtained from the APG by measuring and subtracting the atmospheric pressure at the sea surface from the APG measurement

Lo Bue, Nadia. (2019). CTD dataset (SBE 37-SM @ 1 sample / 5 min) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

The dataset contains sea bottom Conductivity, Temperature and Pressure data (about 1 m above the bottom) acquired through a SBE 37-SM installed on SN-1 station. CTD is used in order to monitoring possible variations of bottom sea water masses in the area

Monna, Stephen. (2019). DPG dataset (SCRIPPS-UCSD DPG prototype v6.0 @ 100 Hz) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

This sensor measures the hydrostatic (water column) pressure variation with respect to the pressure value resulting from the pressure of water above its position and the atmospheric air pressure acting on the sea surface

Lo Bue, Nadia. (2019). ADCP dataset (RDI WorkHorse 600 KHz @ 2 profile / hour) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

The Acoustic Doppler Current Profiler measures the water velocity using the physical Doppler shift principle. The transducer generates a pulse of sound at a known frequency that travels through the water and is reflected in all directions by particulate matter (e.g., sediment, biological matter, bubbles). Some portion of the reflected energy travels back at the transducer where the processing electronics measure the change in frequency. The Doppler shift measured by the transducer reflects the velocity of the water along the axis of the acoustic beam. The ADCP operates using three transducers generating beams with different orientations relative to the water flow then the measured velocity by each ADCP transducer is the projection of the 3D velocity onto the axis of its acoustic beam

Embriaco, Davide. (2019). Hydrophone dataset (SMID DT-405D(V)1 @ 2 kHz) from INGV/NEMO-SN1 seafloor platform during EMSO-MIUR project in TestSite site (East Sicily), part of network.

The dataset contains seafloor pressure data acquired by the seismic hydrophone installed on NEMO-SN1 observatory in the frequency band 50mHz - 1kHz. Pressure is sampled at 2kHz rate by two A/D converter (12 bit) which supply two data channel (with low, 30dB and high, 60 dB gain). Pressure data are stored in counts units; 1 count corresponds to 0.546 Pa and 0.0172 Pa for low and high gain channel respectively. Absolute time reference is available thanks to GPS data embedded in each packet of data and distributed from land station to seafloor. The wide frequency range allows to study acoustic ambient noise in the deep water, detect sperm whale and cetaceans and detect seismic signals. It was designed to be able to detect also low frequency hydroacustic signal generated by a tsunami in case this was generated by large seismic event on the seafloor