On the generation mechanisms of fluid‐driven seismic signals related to volcano‐tectonics. Issue 2 (21st January 2017)

• Record Type: Journal Article
• Authors: Fazio, Marco; Benson, Philip M.; Vinciguerra, Sergio
• Is Part Of: Geophysical research letters. Volume 44:Issue 2(2017)
• Page Start: 734
• Page End: 742
• Publication Date: 2017-01-21
• Subjects: acoustic emissions -- triaxial experiments -- decompression experiments -- fluid‐induced seismicity -- fluid phases -- tremor; Geophysics -- Periodicals; Planets -- Periodicals; Lunar geology -- Periodicals; 550
• DOI: 10.1002/2016GL070919
• Languages: English
• ISSNs: 0094-8276

Abstract

Abstract: The generation mechanics of fluid‐driven volcano seismic signals, and their evolution with time, remains poorly understood. We present a laboratory study aiming to better constrain the time evolution of such signals across temperature conditions 25 to 175°C in order to simulate a "bubbly liquid." Simulations used pressures equivalent to volcanic edifices up to 1.6 km in depth using a triaxial deformation apparatus equipped with an array of acoustic emission sensors. We investigate the origin of fluid‐driven seismic signals by rapidly venting the pore pressure through a characterized damage zone. During the release of water at 25°C broadband signals were generated, with frequencies ranging from 50 to 160 kHz. However, the decompression of a water/steam phase at 175°C generated a bimodal spectrum of different signals, in the range 100–160 kHz. These new results are consistent with natural signals from active volcanoes, such as Mount Etna, and highlight the role of fluid and gas phases (such as bubbly liquids) in generating different types of volcano‐tectonic seismicity. Key Points: Fluid decompression tests in triaxially deformed Etna basalt test Use of acoustic emission sensors to monitor fluid‐induced microseismicity Characteristic spectra of fluid‐driven seismic activity controlled by the number of phase and pore pressure evolution