Volcanologist Lukáš Krmíček from the Institute of Geotechnics travelled to Santorini in June to investigate how hydrothermal processes affect the strength, porosity and other mechanical properties of volcanic rocks, and how these changes may influence the long-term stability of volcanic complexes. During the field campaign, he collected samples of fresh lava from the 20th-century eruptions of Nea Kameni, as well as rocks strongly altered by sulphur-rich fumaroles. Sampling was carried out in coordination with Greek colleagues from the Institute for the Study and Monitoring of the Santorini Volcano (ISMOSAV) and the National and Kapodistrian University of Athens (NKUA).

Santorini is one of the most extensively studied volcanic regions in the world. It has been volcanically active for more than half a million years, and at least twelve Plinian eruptions have occurred over the past 350,000 years. These are exceptionally powerful explosive eruptions that propel volcanic ash and pumice tens of kilometres into the atmosphere. Several of these eruptions were so powerful that the central part of the volcano collapsed, forming a large circular depression known as a caldera.

This caldera is responsible for the distinctive shape of the Santorini archipelago today.

Major eruptions occur here at intervals of approximately 10,000–30,000 years. The current period is characterised by the growth of the Nea Kameni volcanic centre within the caldera and the gradual replenishment of the magmatic system. Lukáš Krmíček collected numerous samples in this area, focusing primarily on young volcanic rocks. These provide an opportunity to investigate the direct effects of hydrothermal alteration on the strength and stability of lava bodies.

In recent years, scientists have focused particularly on the relationship between Santorini and the submarine volcano Kolumbo, located approximately 15 km northeast of the centre of the Santorini caldera. Recent geological and geophysical studies indicate that the two volcanic systems are connected by a shared deep magmatic system. Its activity was also demonstrated by the seismic crisis in early 2025, when thousands of earthquakes led to the declaration of a state of emergency and the temporary evacuation of the island.

In addition to Nea Kameni, samples were collected from several other important geological sites on Santorini. These included the oldest volcanic rocks in the archipelago, dating back more than half a million years; lava from the Skaros volcanic neck, formed nearly 70,000 years ago; and deposits from the famous Minoan eruption approximately 3,600 years ago. This catastrophic eruption created the present-day Santorini caldera, buried the city of Akrotiri beneath tens of metres of pumice and ash, and significantly contributed to the decline of the Minoan civilisation in the eastern Mediterranean.

The results of laboratory testing will contribute to a better understanding of the processes affecting the long-term stability of active volcanoes and associated geological hazards. The research also opens up new opportunities for cooperation between researchers at the Faculty of Civil Engineering at BUT and leading Greek institutions involved in volcanic research and monitoring in the eastern Mediterranean. It builds on the long-standing research focus of the Institute of Geotechnics at the Faculty of Civil Engineering BUT on the mechanical properties of geomaterials and their importance in geological hazard assessment.