Using the submarine cable dedicated to telecommunications, the researchers were able to monitor the seismic events associated with the awakening of the island of Vulcano.
By analyzing low-frequency recordings of dynamic deformations acquired using Distributed Acoustic Sensing (DAS) technology on the island of Vulcano in Italy, a team of researchers from the National Institute of Geophysics and Volcanology (INGV), the GeoForschungsZentrum of Potsdam (GFZ) and the University of Catania (UniCT) have demonstrated that optical fiber telecommunication cables, in association with innovative artificial intelligence algorithms, they can contribute to the understanding and monitoring of hydrothermal systems in volcanic areas.
These are the results of the study "Distributed dynamic strain sensing of very long period and long period events on telecom fiber-optical cables at Vulcano, Italy”, recently published in the journal Scientific Reports.
Seismic signals of a volcanic nature are useful for understanding the state of the volcano and therefore can provide valuable information for estimating the danger level of the volcano itself. By interrogating through a DAS device an on-shore and off-shore fiber optic telecommunications cable linking the island of Vulcano to Sicily, the team was able to automatically detect seismic-volcanic events. During the 1-month acquisition, the researchers detected 1488 events with a large variety of waveforms composed of two main frequency bands (0,1 to 0,2 Hz and 3 to 5 Hz) with various relative amplitudes.
Volcanic risk assessment requires geophysical, geochemical and geological information which is acquired through scientific instrumentation installed on the sides and tops of volcanoes. In particular, the nature of very long period (VLP) and long period (LP) seismic signals in volcanoes has been the subject of scientific debate for several decades.
Understanding the mechanisms of origin of the LP and VLP signals is, therefore, a fundamental component for assessing the state of volcanic activity and thus contributing to the definition of the correct alert level.
Broadband seismometers have so far been the main tools for studying the signal origin processes in volcanoes and are usually installed on the volcanic edifice to capture the events and estimate their source. However, in the small volcanic islands, the underwater environment requires the installation of particularly expensive and difficult to manage and maintain instrumentation.
Thanks to the ability to interrogate submarine cables even at long distances, up to tens of km, the DAS devicestransform the fiber into a dense array of distributed sensors that are easier to manage than traditional sensors. This ability allows you to intervene easily and quickly to acquire useful signals to give rapid responses to volcanic crises.
The acquisition of DAS signals produces a huge amount of data and presents an IT challenge to store, access and process it. During the experiment at Vulcano, approximately 20 Terabytes of data were continuously acquired.
Therefore, the team developed new IT solutions to collect, manage and analyze the huge volumes of data using recent technological advances in High Performance Computing (HPC) and artificial intelligence.
The study demonstrated that the interrogation of the fiber optic submarine cable which connects the island of Vulcano to Milazzo,associated with dedicated processing algorithms, can effectively contribute to seismic monitoring and understanding the origin of low-frequency seismic signals generated by hydrothermal activity.
Link to the study: https://www.nature.com/articles/s41598-023-31779-2
Useful links: National Institute of Geophysics and Volcanology (INGV)
