To analyze the conditions leading up to the 2018 flank collapse at Anak Krakatau, Fiene Stopke—who is doing her PhD within the PRE-COLLAPSE project—combined direct shear experiments on volcanic ash and scoria with numerical models. The study, conducted in collaboration with colleagues, was just published in the Journal of Geophysical Research: Solid Earth. The results show that within the volcano there must have been a pre-existing "proto-shear plane" that lead to the slow deformation of the volcano prior to the collapse. Triggered by an external factor such as an earthquake or dike intrusion, the flank began to move faster. This accelerated movement weakened the volcanic material within the proto-shear plane, ultimately leading to the collapse. The study highlights the importance of monitoring the submarine part of the volcano, as it is likely that sliding originates at the foot of the volcano. It emphazises that studying material properties and modelling weak planes within the volcano are crucial for assessing flank collapse potential and hazard.

Many volcanoes around the world show signs of gravitational collapse—ranging from slow deformation at just a few millimetres per year to sudden, catastrophic landslides. In her Master thesis, Julia Knüppel used analogue modelling to study these slow-moving, gravity-driven processes that can eventually lead to large-scale volcanic collapse.

PRE-COLLAPSE Writing Retreat, Workshop, and Field Trip in the Eifel Volcanic Region

One year after the R/V SONNE cruise, GEOMAR researchers returned to the waters around Anak Krakatau to gain a deeper understanding of an intriguing discovery made during their previous expedition. This latest endeavour, part of an on-going collaboration with BRIN, Indonesia’s national research and innovation agency, aimed not only to collect geological samples but also to strengthen scientific ties between GEOMAR and Indonesian researchers.

Fiene Matthies wrote about her PHD studies, and her visit to Professor Julia Morgan at the Earth, Environmental and Planetary Sciences department at Rice University, where she selected samples from Kilauea’s submarine flank.

METEOR Expedition M198 explores flank instability

REconstructing VOLcanic erUptions and Tsunamis Of Krakatau VolcaNo

In August 2023 the PRE-COLLAPSE team and other international scientists visited Indonesian waters with research vessel R/V SONNE to decode the mechanisms behind the devastating volcanic events at Anak Krakatau in 1883 and 2018.

Marks imprinted in the Aegean seafloor help to better assess the hazards of volcanic tsunamis

With the French oceanographic research vessel N/O Téthys II Morelia Urlaub had the opportunity to download the most recent seafloor geodetic data from the GeoSEA network at Etna’s southeastern offshore flank.

Researchers from PRE COLLAPSE and accompanying projects are monitoring Etna’s southeastern flank that is slowly moving into the sea. To analyse the behaviour of the sliding blog, on land two creepmeters have been installed in July 2022 to complement the offshore GeoSEA array that has been running since 2016.