Latest developments in measurement and geodetic monitoring techniques for shallow water volcanic areas subjected to vertical deformation phenomena (application on Campi Flegrei caldera).

The monitoring of seabed deformation in coastal areas within active volcanic systems can be achieved through various techniques. However, several challenges must be addressed when conducting measurements in shallow marine environments. For instance, biological factors, such as biofouling, can compromise the long-term operability of instruments, while human activities, including overfishing and dragging operations, may cause physical damage to seafloor equipment. Additionally, temporal variations in seawater properties further complicate data analysis and interpretation.

To address these limitations, novel methodologies have been developed for monitoring seabed deformation in the Campi Flegrei volcanic region (southern Italy). Since 2016, a permanent marine infrastructure, MEDUSA (Marine Equipment for the Detection of Underwater Seafloor Activities), has been deployed within the marine sector of the Campi Flegrei caldera. This system consists of four spar buoys equipped for real-time geophysical monitoring of volcanic activity.

The methodologies implemented in MEDUSA include high-precision pressure measurements at the seafloor, sea-level monitoring, and the integration of GPS receivers mounted on the buoys. These advancements have significantly enhanced the geodetic and geophysical monitoring capabilities in the area, contributing to a more comprehensive understanding of ground deformation patterns within the marine sector of the Campi Flegrei caldera.

The infrastructure is also able to accurately localize seismic events at sea, given the high seismic activity of the area, while simultaneously reducing the detection threshold.

To further improve covered area, we plan to deploy a network of cost-effective and autonomous seafloor instrumented modules, applying the new methodologies developed.

The presentation will cover the main techniques for measuring seafloor deformation, the solutions adopted in the Campi Flegrei region, the findings from nine years of continuous monitoring, and the planned advancements for future research.