Early and accurate detection of seismic events It is crucial in volcanic areas like the Canary Islands, where activity associated with magmatic movements and eruptions is a constant. Scientific institutions and authorities have traditionally relied on land-based seismometer networks to monitor these phenomena, but the island's geographical characteristics limit their reach and precision, especially in the underwater environment.
In the face of these challenges, Marine hydrophones emerge as a promising tool to improve seismic monitoring in island areas. This is reflected in various studies led by teams from the University of La Laguna, the National Geographic Institute (IGN), the Spanish Institute of Oceanography (IEO-CSIC), and the University of Concepción in Chile, which highlight the usefulness of these sensors in monitoring volcanic islands like the Canary Islands.
How do hydrophones work in seismic monitoring?
Deployment of hydrophones in shallow waters around the islands allows record underwater acoustic signals associated with seismic movements. These devices, located near the seafloor but out of reach of the strongest currents, capture changes in water vibrations generated by volcanotectonic earthquakes. The method It is less expensive and easier to operate and maintain than the installation of seismometers directly on the seabed, which represents a clear advantage for monitoring in remote or difficult-to-access areas.
During the Tajogaite volcano eruption in 2021, the experts carried out an experiment consisting of installing a hydrophone at a depth of 77 meters and about 7 kilometers from the volcanic mouth, in order to Analyze the underwater soundscape coinciding with the eruptive activity. The aim was to test whether hydroacoustics could provide significant information about seismic phenomena in real time.
Results and correlation of acoustic and seismic signals
The study compared the acoustic data collected by the hydrophone with those from a ground-based seismic station located 12 kilometers from the volcano and with the IGN archive. In total, 712 impulsive acoustic signals were identified. that coincided temporally with seismic events recorded on land. Analyzing both independent data sets, the researchers concluded that Hydrophones floating near the seafloor are capable of capturing volcanotectonic signals. as effective as conventional seismometers on land.
In addition, it was possible to demonstrate a direct correlation between the sound pressure level of the acoustic signals recorded by the hydrophone and the magnitude of the earthquakes calculated by the ground equipment. This relationship indicates that Acoustic energy captured in the marine environment accurately reflects the intensity of seismic events occurred near the islands.
Advantages of hydrophones and practical applications
Among the main benefits of this technology are: Hydrophones are more affordable and manageable compared to expensive ocean-bottom seismometers. They also allow for broader and more flexible coverage, effectively complementing ground stations and improving the location of epicenters in areas where physical access is limited or the distribution of ground-based sensors is restricted by island topography.
Experts propose the integration of marine passive acoustic monitoring with the land seismic network to optimize monitoring and analysis in volcanic archipelagos. This would facilitate faster and more coordinated response to eruptions and more detailed information would be obtained to investigate the evolution of seismic episodes, supporting civil protection and volcanic risk management decisions.
Implications for risk management on volcanic islands
La shallow water hydroacoustics It is presented as a valid alternative to improve the detection and quantification of earthquakes in island areas. Results have been published in scientific journals such as Scientific Reports They reinforce surveillance against eruptive phenomena and help anticipate possible emergencies, always in coordination with ground monitoring methods and established institutional protocols.
Currently, collaboration between technological innovation, research and citizen preparation, which includes training and drills coordinated with European civil protection agencies, allows the Canary Islands have more robust systems to address volcanic and seismic threats.
Advances in the detection and analysis of underwater seismic signals increase the safety and responsiveness of island communities to the challenges posed by the oceanic volcanic environment, providing more comprehensive knowledge and preventing potential natural disasters.
