Fig. 4: Evolution of the 2025 Santorini crisis.
From: Volcanic crisis reveals coupled magma system at Santorini and Kolumbo
a, The preparatory phase from June 2024 to January 2025. The influx of magma from a mid-crustal magma reservoir into the shallow magma reservoir beneath Santorini resulted in surface uplift and increased seismicity at the caldera. The green 3D body shows the locations of a low P-wave velocity anomaly L4 (21% lower νP). High-velocity anomalies H1 and H2 are interpreted as rheologically strong layers, whereas low-velocity anomalies L3 and L4 represent branches of a mid-crustal magma storage system at different depths (see refs. 30,31). b, Volcano–tectonic crisis: diking and faulting. Starting on 27 January 2025, a dike intrusion was initiated from a mid-crustal magma reservoir and propagated laterally upwards into the Anhydros block. Seismicity (coloured dots) occurred at the tip and boundaries of the dike rupture, and shallow crustal normal faults were activated by changes in stress and fluid pressure (black lines). The concurrent deflation of a shallower mid-crustal melt reservoir led to subsidence, which was measured at Santorini and Kolumbo. Scale bar, 10 km. VE, vertical exaggeration.
