Electronic Theses and Dissertation

Tsunami akibat longsoran bawah laut (submarine landslide) merupakan
salah satu bencana alam yang merusak, terutama di wilayah pesisir. Tujuan utama
penelitian ini adalah untuk mengevaluasi pengaruh titik awal pelepasan longsoran
(initiation point) terhadap tinggi gelombang (wave height) dan waktu kedatangan
gelombang (Estimated Time of Arrival / ETA). Penelitian dilakukan melalui
pemodelan fisik pada saluran flume menggunakan model batimetri yang diperoleh
dari peta BATNAS (Batimetri Nasional). Data longsoran diperoleh melalui
pelepasan massa padat pada beberapa variasi ketinggian. Data gelombang direkam
menggunakan sensor wave gauge, sementara kecepatan aktual longsoran dihitung
melalui analisis video pengujian secara frame-by-frame. Untuk meningkatkan
akurasi pembacaan data, dilakukan koreksi baseline berdasarkan rata-rata sinyal 9
detik awal dan pemulusan data menggunakan metode SMA (Simple Moving
Average) lima data, hubungan antara parameter longsoran dan respons gelombang
dianalisis menggunakan regresi linier untuk menghasilkan korelasi antara variabel
variabel serta divisualisasikan melalui grafik stockchart. Hasil analisis
menunjukkan bahwa semakin dekat titik awal pelepasan longsoran (initiation point)
dengan permukaan air, maka ketinggian gelombang yang dihasilkan semakin besar,
seperti di wave gauge 07 dengan persamaan regresi H = -0.0188P + 0.1302 untuk
P ≥ 17,5 serta nilai determinasi sebesar R² = 0.9301. Ketinggian gelombang
tertinggi yang tercatat pada simulasi S5X10B sebesar 0.8936 cm atau 4,91 m dalam
skala prototipe, sedangkan pengaruh antara initiation point dan waktu
kedatangannya tidak stabil dan lemah pada beberapa titik pengamatan. Hasil
penelitian ini diharapkan dapat menjadi masukan dalam pengembangan sistem
peringatan dini tsunami lokal, khususnya di wilayah dengan topografi dasar laut
yang curam, seperti Teluk Palu.
Kata Kunci : tsunami,submarine landslide, teluk palu, model fisik

Tsunamis generated by submarine landslides are among the most destructive natural disasters, particularly in coastal areas. The primary objective of this study is to evaluate the influence of the landslide initiation point on wave height and Estimated Time of Arrival (ETA). The research was conducted through physical modeling in a laboratory flume using a bathymetric model derived from the Indonesian National Bathymetry Map (BATNAS). Landslide events were simulated by releasing solid masses from various initial heights. Wave data were recorded using wave gauge sensors, while the actual landslide velocities were determined through frame-by frame analysis of video footage. To improve data accuracy, baseline correction was performed using the average of the first 9 seconds of the recorded signal, and the data were smoothed using a five-point Simple Moving Average (SMA) method. The relationship between landslide parameters and wave response was analyzed using linear regression, and the correlations between variables were visualized through stockchart graphs. The results indicate that the closer the landslide initiation point is to the water surface, the greater the resulting wave height, as observed at wave gauge 07 with a regression equation of H = -0.0188P + 0.1302 for P ≥ 17.5, and a coefficient of determination R² = 0.9301. The highest recorded wave height occurred in simulation S5X10B at 0.8936 cm equivalent to 4.91 m in prototype scale. Meanwhile, the relationship between initiation point and wave arrival time was found to be weak and inconsistent across several observation points. These research are expected to contribute to the development of localized tsunami early warning systems, especially in regions with steep underwater topography, such as Palu Bay. Keywords: tsunami, submarine landslide, Palu Bay, physical model