Electronic Theses and Dissertation

Tsunami Palu 2018 dipicu oleh gempa M_w 7,5 di sepanjang Sesar Palu-Koro, namun deformasi sesar mendatar tidak sepenuhnya menjelaskan tinggi gelombang di pesisir. Kondisi ini mengindikasikan adanya kontribusi signifikan dari sumber non-seismik seperti longsoran bawah laut (submarine landslide). Penelitian ini bertujuan menginvestigasi karakteristik morfologi dan morfometrik longsoran bawah laut di Teluk Palu menggunakan data batimetri resolusi tinggi pascatsunami 2018. Penelitian dilaksanakan dari Oktober 2025 hingga Januari 2026 menggunakan data survei Multibeam Echosounder (MBES) hasil kerja sama TDMRC Universitas Syiah Kuala dan STMKG. Data diolah dengan perangkat lunak Surfer untuk menghasilkan peta kemiringan lereng (slope map) serta mengekstraksi parameter geometri spesifik berdasarkan pendekatan Puga-Bernabéu et al. (2022). Interpretasi batimetri berhasil mengidentifikasi enam area longsoran bawah laut, yaitu PB1, PB2, MP1, PS1, PT1, dan PT2. Analisis morfometrik menunjukkan geometri yang dinamis dengan panjang longsoran berkisar antara 400–1.300 meter dan relief vertikal jatuh berkisar 60–145 meter. Tipologi longsoran terbagi menjadi tiga kategori Intra-slope Landslide (PB1) yang berkembang terbatas pada tubuh lereng; Slope-detached Landslide (PB2 dan PT1) berupa kegagalan tunggal dengan bidang gelincir planar; serta Landslide Complex (MP1, PS1, dan PT2) yang mendominasi kawasan teluk dengan karakteristik runtuhan multipase bertingkat dan acak (chaotic). Kesimpulan penelitian menunjukkan bahwa ketidakstabilan lereng bawah laut di Teluk Palu memiliki karakteristik geometri dan mekanisme pemicu yang beragam. Dominasi tipe landslide complex membuktikan terjadinya kegagalan lereng bertahap (retrogressive failure) akibat gangguan tektonik aktif yang berulang.

The 2018 Palu tsunami was triggered by an M_w 7.5 earthquake along the Palu-Koro Fault, yet the strike-slip fault deformation does not fully explain the observed wave heights along the coast. This condition indicates a significant contribution from non-seismic sources, such as submarine landslides. This study aims to investigate the morphological and morphometric characteristics of submarine landslides in Palu Bay using post-2018 tsunami high-resolution bathymetric data. The research was conducted from October 2025 to January 2026 utilizing Multibeam Echosounder (MBES) survey data acquired through a collaboration between TDMRC Universitas Syiah Kuala and STMKG. The data were processed using Surfer software to generate slope maps and extract specific geometric parameters based on the approach by Puga-Bernabéu et al. (2022). Bathymetric interpretation successfully identified six submarine landslide areas, namely PB1, PB2, MP1, PS1, PT1, and PT2. Morphometric analysis reveals dynamic geometry, with landslide lengths ranging from 400 to 1,300 meters and total vertical drop reliefs ranging from 60 to 145 meters. The landslide typology is classified into three categories Intra-slope Landslide (PB1), which develops restrictively within the continental slope body; Slope-detached Landslide (PB2 and PT1), characterized by a singular failure along a planar slip surface; and Landslide Complex (MP1, PS1, and PT2), which dominates the bay area with multi-fase, stepped, and chaotic failure features. In conclusion, the submarine slope instability in Palu Bay exhibits diverse geometric characteristics and triggering mechanisms. The dominance of the landslide complex type proves the occurrence of multi-stage retrogressive slope failures driven by recurrent active tectonic disturbances.