Within the Tsunami_Risk project we want to investigate the occurrence of cascading geohazards. Two tsunami events that occurred in Indonesia in 2018 serve as a starting point. Although the early warning systems developed after the catastrophic tsunami in the Indian Ocean in 2004 have already proven themselves several times by successfully triggering warning processes, these two tsunamis were not detected and therefore claimed numerous victims from the unprepared population and produced high damage. The reason for this is the formation of the tsunami waves. While the early warning systems established in Indonesia were designed for detecting seismically induced tsunamis, it was a cascade of events that triggered the two tsunamis in 2018.
The 2018 tsunamis
On September 28, an earthquake occurred north of the city of Palu, inducing numerous mass movements in Palu Bay. Each of these mass movements triggered tsunami waves whose effects were superimposed and amplified within the bay, causing tsunami waves up to 9 m high that hit the city of Palu. Only three months later, on December 22, the flank of the Anak Krakatau volcano collapsed after a period of increased volcanic activity, and triggered another tsunami.
Objectives of Tsunami_Risk
The aim of the overall project is to identify unstable coastal slopes and to investigate potential tsunamigenic mass movements and their triggering mechanisms in order to detect them in advance and to integrate them into early warning processes.
Identification and investigation of mass movements on tsunamigenic coastal landforms
The research project of the Engineering Geology Department includes the modeling of tsunami-induced mass movements within Palu Bay and the identification of further coastal sections at risk in Indonesia.
Back analysis of the Palu landslides
In a back analysis of the Palu landslides, the relation between the mass movements and the earthquake as a triggering process will be investigated in order to establish critical thresholds for warning systems or hazard assessment. In addition, parameters will be obtained, which can be used for the subsequent calculation of tsunami propagation.
Application to other endangered areas
The knowledge gained from modeling the mass movements of Palu will be used to estimate the hazard to other coastal areas. Potentially affected areas are selected based on their coastal geometry, geology, morphology, seismic activity, and population density. Particularly at risk are narrow bays, straits, fjords, and reservoirs, as superposition and amplification of multiple tsunami waves is possible in these narrow and elongated waters.
Project scientists at the Engineering Geology Department are Katrin Dohmen, Anika Braun, and Tomas Fernandez-Steeger.
Project partners in Germany
Project partners in Indonesia