KETEBALAN ENDAPAN SEDIMEN PASIR LAUT BERDASARKAN DATA SEISMIK DANGKAL SALURAN TUNGGAL DI PERAIRAN TAKALAR, SELAT MAKASSAR

Abstract

Ketebalan dan jenis sedimen dasar laut di suatu lokasi penelitian dapat diketahui dari pengambilan data geologi permukaan dan bawah permukaan dasar laut. Metoda yang digunakan untuk mendapatkan data tersebut di atas antara lain geofisika laut (batimetri, seismik refleksi), geologi (pengambilan contoh sedimen dasar laut). Kegiatan penelitian ini berada di perairan Selat Makassar, di muara sungai sekitar pantai Takalar sebagai sumber sedimen pasir ke arah lepas pantai. Sumber sedimen pasir tersebut diketahui dari hasil pengamatan di lapangan ternyata dipengaruhi oleh energi gelombang, arus sejajar pantai (longshore current) dan arus pasang surut (tidal current). Data geologi bawah permukaan (sub bottom profiling) didapat dengan menganalisa rekaman seismik pantul dangkal untuk mengetahui ketebalan dan luasan sebaran sedimen pasir. Dari analisis data tersebut dilakukan pendekatan perhitungan secara kualitatif sehingga diketahui deposit endapan pasir dengan luas area kurang lebih 9,764 km², dengan asumsi ketebalan rata-rata 3,84 meter maka deposit kurang lebih 224 juta meter³.

Kata Kunci : Seismik refleksi, sedimen pasiran, Takalar, Selat Makasar

The thickness and type of seabed sediments at a research location can be known from surface and subsurface geological data collection. The methods used to obtain the above data include marine geophysics (bathymetry, seismic reflection), geology (sampling of sea floor sediments). This research activity was located in the Makassar Strait waters, at the mouth of the river around the Takalar coast as a source of sand sediment towards the offshore. The source of the sand sediment known from observations in the field was influenced by wave energy, longshore currents and tidal currents. Sub-bottom profiling is obtained by analyzing shallow reflected seismic records to determine the thickness and sand deposition distribution. From the analysis of the data the qualitative calculation approach is carried out so that it is known that the deposition of sand deposits with an area of approximately 9,764 km², assuming an average thickness of 3,84 meters, the deposit reserves of approximately 224 million meters³.

Keyword : seismic reflection, sandy sediment, Takalar, Makasar strait