Magma Displacement Triggered Tens of Thousands of Earthquakes, Santorini Swarm Study Finds
janrinok writes:
Magma displacement triggered tens of thousands of earthquakes, Santorini swarm study finds
Tens of thousands of earthquakes shook the Greek island of Santorini and the surrounding area at the beginning of the year. Now, researchers have published a comprehensive geological analysis of the seismic crisis in the journal Nature.
The researchers-from GFZ Helmholtz Center for Geosciences and GEOMAR Helmholtz Center for Ocean Research Kiel, together with international colleagues-integrated data from earthquake stations and ocean bottom instruments deployed at the Kolumbo underwater volcano seven kilometers away from Santorini and used a newly developed AI-based method for locating earthquakes.
This enabled reconstructing the processes in the underground with unique detail, revealing that around 300 million cubic meters of magma rose from the deep crust and came to rest at a depth of around four kilometers below the ocean floor. During its ascent through the crust, the molten magma generated thousands of earthquakes and seismic tremors.
Santorini is located in the eastern Mediterranean and forms part of the Hellenic volcanic arc, a highly active geological zone. This world-famous island group forms the rim of a caldera, which was created by a massive volcanic eruption around 3,600 years ago.
The active underwater volcano Kolumbo lies in the immediate vicinity. In addition, the region is crossed by several active geological fault zones, which are the result of the African Plate pushing northeast against the Hellenic Plate. Earth's crust beneath the Mediterranean region has broken up into several microplates that shift against each other, and in some cases subduct and melt, thus sourcing volcanic activity.
Santorini has produced multiple eruptions in historic times, most recently in 1950. In 1956, two severe earthquakes occurred in the southern Aegean Sea, only 13 minutes apart, between Santorini and the neighboring island of Amorgos. These had magnitudes of 7.4 and 7.2 respectively, triggering a tsunami.
The earthquake swarm that initiated in late January 2025 took place in exactly this region. During the crisis, more than 28,000 earthquakes were recorded. The strongest of these reached magnitudes of over 5.0. The severe shaking caused great public concern during the seismic crisis, partly because the cause was initially unclear, being potentially either tectonic or volcanic.
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