Investigasi Volume Gelembung Emisi Gas Menggunakan Water Column Data Multibeam Echosounder (Studi Kasus: Laut Adriatik)

Adriyanti, Syalsabila Eka (2024) Investigasi Volume Gelembung Emisi Gas Menggunakan Water Column Data Multibeam Echosounder (Studi Kasus: Laut Adriatik). Other thesis, Institut Teknologi Sepuluh Nopember.

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Abstract

Dalam survei hidrografi, multibeam echosounder sering digunakan. Penelitian ini menggunakan multibeam echosounder untuk memetakan volume gelembung emisi gas dasar laut di Laut Adriatik, Italia, dengan memanfaatkan data kolom air. Survei dilakukan pada area seluas 1,5 km² di sekitar platform gas berkaki empat pada kedalaman 77 meter, dan melibatkan sepuluh transek paralel sepanjang 1,5 km dengan kecepatan antara 2 s.d. 2,6 m/s dan jarak antar transek 100 meter untuk mencapai tumpang tindih 50%. Data yang diperoleh pada 12 September 2018 dari National Research Council, Institute of Marine Biological Resources and Biotechnologies di Italia, menggunakan Kongsberg EM2040CD sepanjang 6.132,664 km, menunjukkan kemampuan multibeam echosounder untuk mengidentifikasi karakteristik yang tidak terdeteksi di permukaan air dan dasar laut. Visualisasi data kolom air mengungkap gelombang akustik dari seepage dasar laut, dengan intensitas pantulan bervariasi antara -63,5 dB hingga 29 dB, mencerminkan reflektansi akustik dari berbagai material dasar laut. Filtering dan pengelompokan menggunakan metode point weight memungkinkan pemisahan gelembung gas dari noise dan gelembung air, menghasilkan ambang batas yang lebih akurat. Digital Terrain Model (DTM) yang dihasilkan menunjukkan konsistensi dengan data kolom air yang telah difilter, memperlihatkan konsentrasi gelembung gas pada area permukaan DTM yang tidak rata, mengindikasikan adanya emisi gas. Volume gelembung gas dihitung dengan memvisualisasikan titik-titik dalam format 3D menggunakan data ASCII berkoordinat XYZ di Python, menghasilkan volume sebesar 651,123 m³, 108,300 m³, 42,00 m³, 167,20 m³, 186,00 m³, 287,81 m³, dan 45,00 m³.melalui teknik interpolasi dan analisis volumetrik 3D. Penelitian ini memiliki signifikansi yang tinggi karena memberikan tantangan terhadap metode Carbon Capture and Storage (CCS) dengan mengkaji pelepasan karbon kembali ke laut. Selain itu, penelitian ini berkontribusi dalam mengidentifikasi sumber emisi, mengkuantifikasi volume gas yang dilepaskan, serta memahami distribusi kedalaman emisi, sehingga menyediakan data berharga untuk evaluasi CCS laut. Penggunaan sistem data kolom air dari multibeam echosounder terbukti menjadi alat yang efektif dalam menyelidiki emisi gas dasar laut, membantu dalam mengidentifikasi sumber emisi dan mengkuantifikasi volume gas yang diemisikan.
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In hydrographic surveys, multibeam echosounders are frequently employed. This study utilized a multibeam echosounder to map the volume of seabed gas bubble emissions in the Adriatic Sea, Italy, leveraging water column data. The survey covered a 1,5 km² area around a four-legged gas platform at a depth of 77 meters, involving ten parallel transects spanning 1.5 km each, with speeds ranging from 2 to 2.6 m/s and transect spacing of 100 meters to achieve 50% overlap. Data collected on September 12, 2018, from the National Research Council, Institute of Marine Biological Resources and Biotechnologies in Italy, using the Kongsberg EM2040CD over 6.132,664 km, demonstrated the multibeam echosounder's capability to identify characteristics not detectable at the water surface and seabed. Visualization of the water column data revealed acoustic waves from seabed seepage, with reflection intensities varying between -63,5 dB to 29 dB, reflecting acoustic reflectivity from various seabed materials. Filtering and clustering using point weight methods allowed separation of gas bubbles from noise and water bubbles, yielding more accurate threshold boundaries. The Digital Terrain Model (DTM) generated showed consistency with filtered water column data, indicating gas bubble concentrations in uneven DTM surface areas, suggesting gas emissions. Gas bubble volume was calculated by visualizing points in 3D ASCII XYZ coordinate format using Python, resulting in volumes of 651,1225 m³, 108,30 m³, 42,00 m³, 167,20 m³, 186,00 m³, 287,81 m³, and 45,00 m³ through interpolation and 3D volumetric analysis techniques. This research is highly significant as it challenges Carbon Capture and Storage (CCS) methods by studying carbon re-release into the sea. Moreover, it contributes to identifying emission sources, quantifying emitted gas volumes, and understanding emission depth distributions, providing valuable data for marine CCS evaluations. The utilisation of water column data systems from multibeam echosounders has proven to be an efficient technique for investigating seafloor gas emissions, assisting in the identification of emission sources and quantifying emitted gas amounts.

Item Type:	Thesis (Other)
Uncontrolled Keywords:	Water Column Data, Multibeam Echosounder, Threshold Determination, Gas Seepage, Bubble Volume, Data Kolom Air, Multibeam Echosounder, Penentuan Ambang Batas, Rembesan Gas, Volume Gelembung
Subjects:	G Geography. Anthropology. Recreation > GC Oceanography G Geography. Anthropology. Recreation > GC Oceanography > GC1018.5 Ocean zoning. T Technology > TC Hydraulic engineering. Ocean engineering
Divisions:	Faculty of Civil, Planning, and Geo Engineering (CIVPLAN) > Geomatics Engineering > 29202-(S1) Undergraduate Thesis
Depositing User:	Syalsabila Eka Adriyanti
Date Deposited:	29 Jul 2024 08:52
Last Modified:	29 Jul 2024 08:52
URI:	http://repository.its.ac.id/id/eprint/109840

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