Monitoring underwater volcano degassing using fiber-optic sensing

Area of Science:

• Geophysics
• Volcanology
• Environmental Monitoring

Background:

• Continuous monitoring of volcanic gas emissions is vital for eruption prediction.
• Underwater volcanic degassing is poorly understood and quantified.
• Fiber-optic based Distributed Acoustic Sensing (DAS) offers high-resolution vibration detection.

Purpose of the Study:

• To explore the potential of DAS technology for monitoring underwater volcanic degassing.
• To detect and analyze acoustic signals associated with underwater bubble emissions.
• To classify bubble events and understand gas seepage patterns.

Main Methods:

• An experiment was conducted at Laacher See volcano, Germany.
• A fiber-optic cable was deployed in the lake and interrogated using a DAS system.
• Acoustic signals were detected, analyzed, and classified using clustering algorithms.

Main Results:

• Numerous acoustic signals correlated with underwater bubble emissions were detected.
• Three distinct bubble types with characteristic waveforms were identified.
• Bubble events were classified into four clusters based on temporal and spectral features.
• Gas seepage patterns and their temporal evolution were elucidated.

Conclusions:

• DAS technology shows significant potential for revolutionizing underwater degassing monitoring.
• The study provides valuable data for understanding volcanic processes and estimating gas emissions.
• DAS is applicable to other environmental monitoring, including carbon capture and methane leak detection.