TDMRC Conducted Bathymetric Survey Campaign along the Palu Bay of Central Sulawesi

Palu, Indonesia – Under Indonesia Disaster Resilience Initiative Project (IDRIP) managed by Indonesia Climate, Geophysics and Meteorological Agency (BMKG) funded by World Bank, Tsunami and Disaster Mitigation Research Center (TDMRC) Universitas Syiah Kuala (USK) sent a team of surveyors to the Palu Bay of Central Sulawesi. The team was aimed at conducting a series of bathymetric surveys along the Palu Bay. The team consisted of five persons led by Dr. Haekal Azief Haridhi.  The team members were Nadri Pratama Putra, M Zawil Kiram, Haddad Rahmat, and Fahrur Rozi.

The campaign was conducted started from September 29 until October 8, 2024. The team carried the surveys using Multi-Beam Echo-sounder (MBES) accompanied by a set of navigation system. Figure 1 and 2 show the installation of the equipment on the boat during the surveys. Figure 3 shows the tracks of the surveys conducted by the team. The equipments are able to measure detailed bathymetric data until ~200 m deep. The surveys were aimed at collecting a series of updated bathymetric data around nearshore of the bay and at calculating sediment accumulations after several years of the 2018 Palu Tsunami.

Figure 1. The installation process by TDMRC Team at the Palu Bay.

Figure 1. The installation process by TDMRC Team at the Palu Bay.

Figure 2. The MBES and Naviagation System Sensors have been installed at the boat.

Figure 2. The MBES and Naviagation System Sensors have been installed at the boat.

Figure 3. The tracks of the MBES surveys along the Palu Bay (blue lines).

Figure 3. The tracks of the MBES surveys along the Palu Bay (blue lines).

A temporary result can be seen in Figure 4. In 2018, a tsunami was generated by combination between earthquake and coastal landslides. The sources of the landslides were identified by a number of publications.

Figure 4. Results of the bathymetric surveys, as in October 2024.

Figure 4. Results of the bathymetric surveys, as in October 2024.

The bay is characterized by its long and deep channel spanning the north to the south direction divided the Central Sulawesi into two parts. Along the bay, there are number of active river mouths with rich sources of inland sediment. After about 6 years from the event, there has not been any study conducted to measure the accumulation of sediment around the nearshore of the bay. Previous surveys have been done to identify the sources of the landslide tsunami. They were performed about 2 years after the tsunami.

The team also attended a focus group discussion (FGD) before conducting the surveys. The FGD was coordinated by Dr. Dimas Salomo J. Sianipar from STMKG-BMKG. The FGD was intended to consolidate the campaign as part of the project titled Development of Formulation of Modeling Parameters for Multi-Source Tsunami. During the FGD, resource persons and participants discussed about the survey planning, integration of data, and earlier similar research conducted along the Palu Bay. Figure 5 shows a photo session with the FGD participants.

Figure 5. The offline participants of the FGD in Palu.

Figure 5. The offline participants of the FGD in Palu.

TDMRC USK also will conduct a series of physical modeling using Tsunami-Wave Flume facilities at TDMRC. The models will use a simplified shape and bathymetry of the bay. Both of the studies, physical model and field surveys, will be integrated to the IDRIP Project in due time. Providing early warning information for non-seismic tsunami events is still among challenging issues in the global context. Therefore, this study will look into more specific information for the Palu Bay area that could support to the development of non-seismic tsunami early warning system for the area.

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