Volcanic unrest as seen from the magmatic source: Reyðarártindur pluton, Iceland

• Published in: Scientific Reports
• Main Authors: Emma Rhodes, Steffi Burchardt, Sonja H. M. Greiner, Tobias Mattsson, Freysteinn Sigmundsson, Tobias Schmiedel, Abigail K. Barker, Taylor Witcher
• Format: Article in Journal/Newspaper
• Language: English
• Published: Nature Portfolio 2024
• Subjects: Medicine; R; Science; Q; Reyðarártindur; Iceland
• Online Access: https://doi.org/10.1038/s41598-023-50880-0; https://doaj.org/article/5cf43c3d07f84bbcbe3f91a6f89631c7

Abstract How the Earth’s crust accommodates magma emplacement influences the signals that can be detected by monitoring volcano seismicity and surface deformation, which are routinely used to forecast volcanic eruptions. However, we lack direct observational links between deformation caused by magma emplacement and monitoring signals. Here we use field mapping and photogrammetry to quantify deformation caused by the emplacement of at least 2.5 km3 of silicic magma in the Reyðarártindur pluton, Southeast Iceland. Our results show that magma emplacement triggered minor and local roof uplift, and that magma reservoir growth was largely aseismic by piecemeal floor subsidence. The occurrence and arrangement of fractures and faults in the reservoir roof can be explained by magmatic overpressure, suggesting that magma influx was not fully accommodated by floor subsidence. The tensile and shear fracturing would have caused detectable seismicity. Overpressure eventually culminated in eruption, as evidenced by exposed conduits that are associated with pronounced local subsidence of the roof rocks, corresponding to the formation of an asymmetric graben at the volcano surface. Hence, the field observations highlight processes that may take place within silicic volcanoes, not accounted for in widely used models to interpret volcanic unrest.