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Session: An Innovative Photonic Vision of Volcanoes and Geothermal Systems

Type: Oral

Date: 10/10/2024

Time: 09:30 AM

Room: Stanley Park Ballroom

Imaging Magma Flow Migration Through a Dike Using Low-frequency DAS Measurements

Tracking the magma flowing pathways is critical to understanding the magmatic evolution, forecasting eruptions, and assessing volcanic hazards. In this study, we demonstrate the use of a telecommunication fiber cable as a dense array of strain meters to image the magma migration kinematics within a dike through low-frequency distributed acoustic sensing (LFDAS) recordings. On 10 November 2023, a 15-km-long dike formed below the Sundhnúkur crater row, crossing the town of Grindavík in the Reykjanes Peninsula of Iceland. Eleven days later, we deployed a DAS interrogator in the Peninsula, converting a 100-km-long telecommunication fiber cable crossing Grindavík into a dense array with 10,000 strain sensors. Since then, six intrusive events have occurred, four of which resulted in fissure eruptions. Clear LFDAS signals emerged tens of minutes to several hours before eruptions, showing consistent spatial strain response throughout these intrusive events. To image the dike opening evolution, we developed a joint finite-fault inversion using both LFDAS strain and GPS displacement. Our results show an ascending intrusion propagating to the surface, coinciding with surface lava fissures during eruptions. For the non-eruptive intrusion, our imaging reveals an intrusion trapped at depth. Our findings highlight the feasibility of using DAS as a dense array of strain meters to provide high-resolution, nearly real-time imaging of subsurface deformations, particularly in active volcanic regions.

Presenting Author: Jiaxuan

Additional Authors