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Abstrak :
Daerah Sukatani berada di Selatan Jawa memiliki potensi terjadi bencana tsunami yang diakibatkan oleh gempa bumi besar dari proses pergerakan di zona subduksi. Catatan sejarah kejadian tsunami di Selatan Jawa masih terbatas, sehingga perlu dilakukan penelitian identifikasi endapan paleotsunami. Daerah Sukatani dipilih sebagai lokasi penelitian karena belum ada penelitian mengenai paleotsunami di daerah ini. Penelitian ini dilakukan untuk mengetahui sejarah kejadian paleotsunami di daerah Sukatani yang masih sangat terbatas. Pengambilan sampel kode KRB 03 sepanjang 193 cm dilakukan di Pantai Karang Bolong, Kecamatan Surade, Kabupaten Sukabumi. Untuk mengetahui lapisan endapan paleotsunami dilakukan beberapa analisis laboratorium seperti analisis ukuran butir (granulometri), loss on Ignition (LOI), geokimia unsur jejak, dan analisis foraminifera. Dari analisis yang terlah dilakukan didapatkan satu lapisan endapan paleotsunami di kedalaman 164 hingga 186 cm. Hasil analisis ukuran butir diketahui lapisan endapan paleotsunami memiliki rata-rata ukuran butir antara kerikil halus hingga pasir halus, sortasi sedang hingga sangat buruk, kurtosis tipe very platykurtic hingga very leptokurtic, dan skewness tipe very fine skewed hingga very coarse skewed. Hasil analisis Loss on Ignition (LoI) diketahui lapisan endapan paleotsunami memiliki kandungan material organik yang rendah dan material karbonat yang lebih tinggi. Hasil analisis geokimia unsur jejak diketahui lapisan endapan paleotsunami memiliki kandungan unsur Ca dan Sr yang lebih tinggi. Hasil analisis foraminifera didapatkan foraminifera bentonik dengan lingkungan neritik tengah yang diperkirakan sebagai sumber endapan paleotsunami. ...... The Sukatani area in southern Java has the potential for a tsunami disaster caused by a large earthquake from the movement process in the subduction zone. The historical record of tsunami events in southern Java is still limited, so it is necessary to conduct research on the identification of paleotsunami deposit. The Sukatani area was chosen as the research location because there was no research on paleotsunami in this area. This research was conducted to determine the history of ancient tsunami events in the Sukatani area which is still very limited. Sampling code KRB 03 along 193 cm was carried out at Karang Bolong Beach, Surade District, Sukabumi Regency. To determine the paleotsunami sediment layer, several laboratory analyzes were carried out such as grain size analysis (granulometry), loss on Ignition (LOI), trace element geochemistry and foraminifera analysis. From the analysis that has been carried out, it is found that one paleotsunami deposit layer is at a depth of 164 to 186 cm. The results of grain size analysis show that the paleotsunami sediment layer has an average grain size of fine gravel to fine sand, moderate to very poor sorting, very platykurtic to very leptokurtic types of kurtosis, and very fine skewed to very coarse skewed types of skewness. The results of the loss on Ignition (LOI) analysis show that the paleotsunami sediment layer has a low content of organic material and higher carbonate material. The results of trace element geochemistry analysis show that the paleotsunami sediment layer has higher levels of Ca and Sr. The results of foraminifera analysis obtained bentonic foraminifera with middle neritic environments which are thought to be the source of paleotsunami deposits.

Abstrak :
Deposit paleotsunami telah ditemukan di berbagai lokasi di Indonesia, diantaranya ialah di kawasan Pacitan, Kulon Progo, Cilacap, Pangandaran, serta kawasan Lebak, Banten. Penelitian kali ini dilakukan dengan tujuan untuk mendapatkan model yang ideal dalam penentuan luasan zona inundasi paleotsunami di sepanjang kawasan pesisir selatan Malingping, Kabupaten Lebak, Provinsi Banten dengan metode pemodelan numerik finite difference melalui perangkat lunak ComMIT yang berbasis sistem MOST (Method Of Splitting Tsunamis). Kegiatan lapangan dilakukan guna mengidentifikasi keberadaan endapan paleotsunami pada kawasan lembahan atau swale. Beberapa skenario seperti peristiwa Pangandaran 2006, Aceh 2004, Tohoku 2011, serta gempa yang bersumber pada kawasan segmen megathrust Selat Sunda, dan megathrust sepanjang selatan Jawa digunakan dalam proses pemodelan untuk melihat karakteristik paleotsunami yang paling mungkin mengendapkan deposit di kawasan penelitian. Pemodelan dilakukan dengan berbagai macam skema yaitu dengan memanfaatkan unit source dengan bentuk segmen-segmen pada zona subduksi pada database ComMIT, serta menggunakan parameter sumber gempa yang dimasukkan secara manual untuk selanjutnya dilakukan pemodelan pada ComMIT. Hasil pemodelan menunjukkan skenario tsunami terburuk yang mungkin pernah terjadi di kawasan penelitian ialah peristiwa tsunami dengan nilai magnitudo mencapai 9.1Mw, dengan jangkauan inundasi maksimum sejauh 5,2 kilometer, serta amplitudo gelombang mencapai 32 meter, yang diperkirakan menjadi peristiwa tsunami yang mengendapkan deposit paleotsunami yang ditemukan di daerah penelitian. ......Paleotsunami deposits have been found in various locations in Indonesia, such as in the Pacitan area, Kulon Progo, Cilacap, Pangandaran, and Lebak, Banten. This research was conducted with the aim of obtaining an ideal model in determining the area of the paleotsunami inundation zone along the southern coastal area of Malingping, Lebak Regency, Banten Province with the finite difference numerical modeling method through ComMIT software based on the MOST (Method Of Splitting Tsunamis) system. Field activities were carried out to identify the presence of paleotsunami deposits in the swale area. Several scenarios such as the Pangandaran 2006, Aceh 2004, Tohoku 2011, as well as earthquakes originating in the Sunda Strait megathrust segment area, and megathrust along the south of Java were used in the modeling process to see the characteristics of paleotsunami that were most likely to produced the tsunami deposits in the study area. Modeling is carried out with various schemes, such as using the ComMIT database unit source in the form of segments in the subduction zone, as well as using earthquake source parameters that are entered manually for further modeling on ComMIT. The modeling results show that the worst tsunami scenario that may have ever occurred in the study area is the tsunami event with a magnitude value of 9.1Mw, with a maximum inundation range of 5.2 kilometers, and a wave amplitude of up to 32 meters, which is estimated to be a tsunami event that deposits paleotsunami deposits found in the study area.

Abstrak :
Pesisir selatan Jawa Timur memiliki potensi kebencanaan terutama tsunami yang cukup tinggi. Untuk tujuan mitigasi, selain memperingatkan warga mengenai bahaya tsunami, perlu juga dilakukan penelitian sejarah kejadian tsunami karena ada kemungkinan pengulangan kejadian. Catatan sejarah tsunami di Jawa Timur banyak mengambil tempat di Pacitan dan Banyuwangi, padahal Lumajang beserta beberapa kabupaten lain menjadi daerah yang sangat rawan tsunami juga. Maka dari itu, penelitian ini memilih daerah Lumajang, lebih tepatnya Kecamatan Tempeh sebagai lokasi penelitian. Penelitian ini bertujuan untuk mengidentifikasi endapan paleotsunami menggunakan empat metode, yaitu granulometri, XRF, Loss on Ignition (LOI), dan analisis mikrofauna. Dari pengamatan di lapangan dan karakter lapisan, berdasarkan pengamatan megaskopis, kandidat endapan paleotsunami pada sampel core JTM-11 terdapat pada kedalaman 142-150 cm. Berdasarkan analisis laboratorium yang berupa analisis granulometri, XRF, dan LOI, didapatkan bahwa karakter dari endapan kandidat paleotsunami tidak menunjukkan karakter endapan paleotsunami yang cukup signifikan dan representatif. Untuk analisis LOI sendiri juga menunjukkan angka yang sangat rendah baik di lapisan kandidat dan non kandidat. Selain itu tidak ditemukan adanya mikrofauna pada lapisan kandidat paleotsunami. ......The southern coast of East Java has quite high potential for disasters, especially tsunamis. For mitigation purposes, apart from warning residents about the dangers of tsunamis, it is also necessary to research the history of tsunami events because there is a possibility of recurrence. Historical records of tsunamis in East Java mostly take place in Pacitan and Banyuwangi, even though Lumajang and several other districts are areas that are very prone to tsunamis as well. Therefore, this research chose the Lumajang area, more precisely Tempeh District as the research location. This research aims to identify paleotsunami deposits using four methods, namely granulometry, XRF, Loss on Ignition (LOI), and microfauna analysis. From field observations and layer characteristics, based on megascopic observations, candidate paleotsunami deposits in the JTM-11 core sample are found at a depth of 142 – 150 cm. Based on laboratory analysis in the form of granulometry, The LOI analysis itself also shows very low numbers in both the candidate and non-candidate layers. Apart from that, no microfauna was found in the paleotsunami candidate layer.