Integrated marine magnetics of the Naples Bay - from old to new data: examples from Naples and Pozzuoli Gulfs (Southern Italy)

The integrated marine magnetics of the Naples Bay, coming from the old to the new data is here tentatively resumed and discussed, focussing on some examples from Naples and Pozzuoli Gulfs (Southern Italy). Significant correlations between geophysical data come from the comparative analysis of seismic and magnetometric datasets. A magnetometer usually measures the strength or direction of the Earth's magnetic field. This last can vary both temporally and spatially for various reasons, including discontinuities between rocks and interaction among charged particles from the sun and the magnetosphere. Most technological advances dedicated to measure the Earth's magnetic field have taken place during World War II. The most common are: the fluxgate, the proton precession, Zeeman-effect, sensor-suspended magnet and satellite magnetometers. The fluxgate and the proton precession magnetometers are effectively the most used for marine surveys, they are both cable drown. The fluxgate magnetometer was the first ship-towed instrument, and it can measure vector components of the magnetic field. Its sensor consists of two magnetic alloy cores that are mounted in parallel configuration with the windings in opposition. The proton precession magnetometer consists of a sensor containing a liquid rich in protons surrounded by a coil conductor. The sensor is towed from the vessel through an armoured coaxial cable whose length depends on vessel length and seafloor depth. Circulating current within the coil generates a magnetic field of approximately two orders of magnitude the Earth's field. In this way, one proton each ten will follow the coil positioning. Stopping the induced magnetic field, the protons will align according to the Earth's magnetic field through a movement of precession.