Figure 1. The TDMRC USK and STMKG team visited IRIDeS, Tohoku University, for a benchmarking study and to consult experts on physical and numerical testing. The TDMRC USK team was represented by Prof. Syamsidik, Dr. Haikal Haridhi, and team, while STMKG was represented by its Chairman, Dr. Deni Septiadi, M.Si, and team
Banda Aceh, September 2024 — The Tsunami and Disaster Mitigation Research Center (TDMRC), Universitas Syiah Kuala (USK), in close collaboration with the Sekolah Tinggi Meteorologi Klimatologi dan Geofisika (STMKG), has successfully conducted a series of physical modeling experiments to investigate the complex tsunami phenomenon that devastated Palu, Central Sulawesi, in 2018. This research activity is carried out under the Indonesia Disaster Resilience Initiative Project (IDRIP) 2024, funded by the World Bank, and aims to strengthen Indonesia’s scientific capacity in tsunami hazard mitigation.
On 28 September 2018, Palu was struck by a 7.5 Mw earthquake followed by a destructive tsunami. The disaster was further compounded by submarine landslides and widespread liquefaction on land, making it one of the most complex and devastating natural catastrophes in recent Indonesian history. While numerical and physical modeling studies, including those by Pakoksung (2019), suggested that submarine landslides may have been responsible for generating significant tsunami waves, the exact triggering mechanisms remain a matter of scientific debate. Understanding this process is crucial not only for solving outstanding scientific questions but also for enhancing Indonesia’s disaster preparedness and resilience.
To deepen the scientific understanding of landslide-generated tsunamis, a joint research team from TDMRC-USK and STMKG conducted benchmarking studies at Irides, Tohoku University, Japan, consulting directly with international experts in physical and numerical tsunami modeling. The Indonesian delegation was led by Prof. Syamsidik and Dr. Haikal Haridhi (TDMRC-USK), along with STMKG’s Chairman, Dr. Deni Septiadi, M.Si.
This collaboration provided valuable input and methodological refinement, which were then applied in large-scale experiments at the TDMRC-USK Tsunami Wave Flume Laboratory, one of Indonesia’s most advanced experimental facilities for tsunami research.
Figure 2. Tsunami flume facility at TDMRC USK
The physical modeling utilized a scaled-down model of Palu Bay, generated from official bathymetric data. The flume, measuring approximately 60 meters in length and 2.5 meters in width, was equipped with a 9-meter Palu Bay model and advanced sensors to measure wave height, velocity, and hydrodynamic parameters.
For the landslide scenarios, semi-elliptical blocks with varying volumes were released at four different locations individually, as well as simultaneously, to replicate potential submarine landslide events. Observation stations were strategically placed to represent key coastal locations around Palu, including:
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Pantoloan Port
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North Taipa
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Tondo-Tadulako
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Lere (West Palu)
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Tipo
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Watusampu (West Palu)
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Banawa (Donggala)
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Donggala Port
Figure 3. Illustration of landslide locations S1, S2, S5, and S6; station locations
The results revealed several critical insights:
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Wave Height Correlation: The height of tsunami waves at observation points was strongly correlated with the depth of the initial landslide location. Landslides occurring at greater depths generated lower surface wave heights, while shallower landslides produced stronger tsunamis.
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Water Accumulation: Significant accumulation of wave energy was observed in the eastern section of Palu Bay, opposite the location of the modeled landslide (Tipo, West Palu).
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Resonance Effects: The experiments detected resonance (seiche) within Palu Bay. The natural frequency of the bay was found to amplify tsunami wave energy, worsening the impact.
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Nonlinear Dynamics: The findings confirm the nonlinear nature of landslide-induced tsunamis, highlighting their complex behavior compared to earthquake-generated tsunamis.
“These results represent an important step forward in understanding the destructive dynamics of the 2018 Palu tsunami,” explained Prof. Syamsidik of TDMRC-USK. “By simulating landslide scenarios in a controlled environment, we can better identify the factors that amplify tsunami impacts and use this knowledge to improve future disaster preparedness.”
Dr. Deni Septiadi, Chairman of STMKG, emphasized the practical value of the research: “This collaboration bridges advanced science with disaster risk reduction policy. The lessons from Palu will not only benefit Indonesia but can also contribute to global understanding of multi-source tsunami hazards.”
Figure 4. Bathymetry model of Palu Bay
The outcomes of this research are expected to directly inform disaster mitigation strategies, early warning systems, and coastal resilience planning. By addressing unresolved scientific questions about the Palu tsunami, the study strengthens the foundation for multi-hazard risk reduction across Indonesia’s vulnerable coastal regions.
The project also highlights the importance of sustained international collaboration and investment in research infrastructure, ensuring that Indonesia remains at the forefront of tsunami science and disaster resilience initiatives.
Figure 5. (a) Monitoring of tsunami wave height measurement process (b) Tsunami landslide simulation process
The research project is also part to implement Sendai Frameworks for Disaster Risk Reduction (SFDRR) where this research attempts to increase risk understanding. Furthermore, this would help to implement Sustainable Development Goals (SDGs), especially Goal No. 11 (Sustainable Cities and Communities), No. 14 (Life Below Water), and No. 17 (Partnership for Goals).
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