Electronic Theses and Dissertation

Peristiwa gempa bumi dan tsunami palu tahun 2018 menyebabkan perubahan morfologi dasar laut yang signifikan serta diduga memicu terjadinya longsor bawah laut pada beberapa lokasi di teluk palu. identifikasi karakteristik longsor bawah laut penting dilakukan untuk memahami proses geomorfologi bawah laut dan potensi bahaya geologi yang dapat terjadi di masa mendatang. penelitian ini bertujuan untuk mengidentifikasi karakteristik morfologi dasar laut dan menentukan tipe longsor bawah laut di teluk palu pasca tsunami 2018 menggunakan data multibeam echosounder (mbes). metode penelitian dilakukan melalui pengolahan data batimetri mbes untuk menghasilkan peta batimetri, peta kemiringan lereng, model tiga dimensi, dan profil morfologi dasar laut. identifikasi longsor dilakukan berdasarkan keberadaan headscarp, break of slope, area evakuasi material, hummocky deposit, dan toe, sedangkan analisis karakteristik longsor dilakukan menggunakan parameter morfometri berupa scar perimeter (sp), scar width (sw), evacuated length (el), deposit length (dl), total length (tl), headscarp slope gradient (hssg), slope gradient (sg), deposit width (dw), deposit thickness (dt), water depth (wd), dan volume longsoran. hasil penelitian menunjukkan bahwa morfologi dasar laut teluk palu didominasi oleh cekungan memanjang berarah utara–selatan dengan kedalaman sekitar 420–660 m dan lereng curam pada bagian barat serta timur teluk. interpretasi morfologi berhasil mengidentifikasi tujuh lokasi longsor bawah laut (ls1–ls7) dengan nilai sp berkisar antara 1.606–6.329 m, hssg antara 28,16°–73,39°, dan volume longsoran antara 1.295.000–74.406.375 m³. berdasarkan karakteristik morfologi dan parameter morfometri, longsor bawah laut dikelompokkan menjadi tipe singular slump, complex, dan singular translational, serta diklasifikasikan sebagai slump wedge dan slide. hasil penelitian menunjukkan bahwa kondisi lereng yang curam dan ketidakstabilan massa sedimen berperan penting dalam pembentukan longsor bawah laut di teluk palu serta dapat menjadi dasar dalam kajian mitigasi bahaya geologi bawah laut di wilayah pesisir. kata kunci: geomorfologi bawah laut, ketidakstabilan lereng, deformasi sedimen, karakteristik morfometri, mitigasi kebencanaan.

The 2018 Palu earthquake and tsunami caused significant changes to the seafloor morphology and are believed to have triggered submarine landslides at several locations within Palu Bay. Identifying the characteristics of these submarine landslides is crucial for understanding submarine geomorphological processes and potential future geological hazards. This study aims to identify seafloor morphological characteristics and determine the types of submarine landslides in Palu Bay following the 2018 tsunami using Multibeam Echosounder (MBES) data. The research methodology involved processing MBES bathymetric data to generate bathymetric maps, Slope gradient maps, three-dimensional models, and seafloor morphological profiles. Landslide identification was based on features such as headscarps, Slope breaks, material evacuation areas, hummocky deposits, and Toes. Morphometric analysis utilized parameters including Scar Perimeter (SP), Scar Width (SW), Evacuated Length (EL), Deposit Length (DL), Total Length (TL), Headscarp Slope Gradient (HSSG), Slope Gradient (SG), Deposit Width (DW), Deposit Thickness (DT), Water Depth (WD), and landslide volume. The results indicate that the seafloor morphology of Palu Bay is dominated by an elongated north-south trending basin with depths ranging from approximately 420 to 660 m, flanked by steep Slopes on the western and eastern sides of the bay. Morphological interpretation identified seven submarine landslide locations (LS1–LS7), with SP values ranging from 1,606 to 6,329 m, HSSG from 28.16° to 73.39°, and landslide volumes from 1,295,000 to 74,406,375 m³. Based on morphological characteristics and morphometric parameters, the submarine landslides were categorized into Singular Slump, Complex, and Singular Translational types, and classified as Slump Wedge and Slide. Research results indicate that steep Slope conditions and sediment mass instability play a significant role in the formation of submarine landslides in Palu Bay and can serve as a basis for assessing submarine geohazard mitigation in coastal areas. Keywords: submarine geomorphology, slope instability, sediment deformation, morphometric characteristics, disaster mitigation.