TY - JOUR T1 - Magma Chamber Detected Beneath an Arc Volcano With Full-Waveform Inversion of Active-Source Seismic Data JF - Geochemistry, Geophysics, Geosystems Y1 - 2022 A1 - Chrapkiewicz, K. A1 - Paulatto, M. A1 - Heath, B. A. A1 - Hooft, E. E. E. A1 - Nomikou, P. A1 - Papazachos, C. B. A1 - Schmid, F. A1 - Toomey, D. R. A1 - Warner, M. R. A1 - Morgan, J. V. KW - full-waveform inversion KW - Kolumbo volcano KW - magma chamber KW - magmatic system KW - Santorini volcanic field KW - volcano tomography AB - Arc volcanoes are underlain by complex systems of molten-rock reservoirs ranging from melt-poor mush zones to melt-rich magma chambers. Petrological and satellite data indicate that eruptible magma chambers form in the topmost few kilometres of the crust. However, very few chambers have ever been definitively located, suggesting that most are too short-lived or too small to be imaged, which has direct implications for hazard assessment and modeling of magma differentiation. Here we use a high-resolution technology based on inverting full seismic waveforms to image a small, high-melt-fraction magma chamber that was not detected with standard seismic tomography. The melt reservoir extends from ∼2 to at least 4 km below sea level (b.s.l.) at Kolumbo—a submarine volcano near Santorini, Greece. The chamber coincides with the termination point of the recent earthquake swarms and may be a missing link between a deeper melt reservoir and the high-temperature hydrothermal system venting at the crater floor. The chamber poses a serious hazard as it could produce a highly explosive, tsunamigenic eruption in the near future. Our results suggest that similar reservoirs (relatively small but high-melt-fraction) may have gone undetected at other active volcanoes, challenging the existing eruption forecasts and reactive-flow models of magma differentiation. VL - 23 UR - https://onlinelibrary.wiley.com/doi/abs/10.1029/2022GC010475 N1 - _eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2022GC010475 ER - TY - JOUR T1 - Relationship Between Active Faulting/Fracturing and Magmatism Around Santorini: Seismic Anisotropy From an Active Source Tomography Experiment JF - Journal of Geophysical Research: Solid Earth Y1 - 2021 A1 - Heath, B. A. A1 - Hooft, E. E. E. A1 - Toomey, D. R. A1 - Paulatto, M. A1 - Papazachos, C. B. A1 - Nomikou, P. A1 - Morgan, J. V. KW - anisotropy KW - faulting KW - magmatism KW - seismology KW - tectonism KW - tectono-magmatism AB - In extending volcanic arcs such as the Aegean, tectonic processes exert a significant control on magmatism. Spanning scales from 1 to 10s of km, volcanic vents, edifices, and eruptive centers follow the orientation of, and are located near, fault zones. Whether this tectonic control on magmatism results from individual faults/fractures weakening the crust or because regional stresses control magma input into the crust is debated. Here we investigate the scales of tectonic and magmatic interactions, specifically focusing on the role of local-scale (<10 km) faults/fractures in controlling magmatism. We infer local-scale fault/fracture orientations from anisotropic active-source P-wave travel-time tomography to investigate tectonic and magmatic interactions in the upper crust of Santorini Volcano, Greece, and the actively deforming region to the east. We use the anisotropy magnitude and seismic velocity reduction to model the relative distribution of both consistently oriented and randomly oriented faults/fractures. Our results show that oriented faulting/fracturing resulting from regional-scale (>10 km) tectonic stresses is distributed broadly across the region at 2–3 km depth, approximately paralleling volcanic/magmatic features. On a local-scale, magmatism is neither localized in areas of higher oriented fault/fracture density, nor is it accommodating enough extensional strain to inhibit oriented faulting/fracturing of host rock. The alignment of magmatic features shows strong tectonic control despite the lack of correlation with local oriented fault/fracture density. These results suggest that magmatic processes are strongly influenced by regional-scale, not local-scale, tectonic processes. We infer regional processes have a greater impact on magmatism than local features due to their greater effect at depth. VL - 126 UR - https://onlinelibrary.wiley.com/doi/abs/10.1029/2021JB021898 N1 - _eprint: https://agupubs.onlinelibrary.wiley.com/doi/pdf/10.1029/2021JB021898 ER - TY - JOUR T1 - Tectonism and Its Relation to Magmatism Around Santorini Volcano From Upper Crustal P Wave Velocity JF - Journal of Geophysical Research: Solid Earth Y1 - 2019 A1 - Heath, B. A. A1 - Hooft, E. E. E. A1 - Toomey, D. R. A1 - Papazachos, C. B. A1 - Nomikou, P. A1 - Paulatto, M. A1 - Morgan, J. V. A1 - Warner, M. R. VL - 124 UR - https://onlinelibrary.wiley.com/doi/abs/10.1029/2019JB017699 ER -