On 22 February 2018 landslide occurred in Pasir Panjang Village, Salem District, Brebes Regency of Central Java Province, Indonesia. About 8 people were died, 4 people were injured and several infrastructures were damaged due to this landslide. This research is carried out to understand geological-geotechnical condition and to study the initiation mechanism of the landslide. Field investigation and UAV mapping are carried out to detect slip surface and define slope geometry. The rainfall-induced pore-water pressure is estimated by using the Slope Infiltration Distributed Equilibrium (SLIDE) model. Then, limit equilibrium method is used to estimate the safety factor of the slope, while the shear strength parameters are determined by applying back analysis approach that compared with data from laboratory tests. The results show that landslide occurred in permeable layer of silty sand overlaid above impermeable andesitic breccia. Results from back analysis indicate that the shear strength parameters and rainfall intensity are strongly influence the stability of slope against landslide.

Abstrak - Kebutuhan masyarakat terkait dengan airtanah semakin meningkat. Penilaian kerentanan airtanah menjadi salah satu cara untuk melindungi sumber daya airtanah agar tidak tercemar. Penelitian ini bertujuan untuk melakukan tinjauan literatur sistematis dan analisis bibliometrik untuk penelitian kerentanan airtanah di Indonesia menggunakan basis data Scopus. Parameter yang dianalisis berupa jumlah terbitan, sumber jurnal/prosiding, kata kunci dan jumlah kutipan. Dari hasil pencarian didapatkan 26 artikel dari 74 penulis pada rentang 2013-2021. Kata kunci populer yang muncul pada penelitian diantaranya groundwater pollution, groundwater vulnerability, groundwater resources, aquifers, dan groundwater. Pengolahan data dan visualisasi menggunakan aplikasi Bibliometrix dan VOSviewer. Dari hasil analisis disusun peta tematik yang menggambarkan 4 kuadran berdasarkan tingkat kepadatan dan tingkat sentralitas. Peta tematik ini diharapkan bisa menjadi acuan untuk penelitian kerentanan airtanah di Indonesia.  Kata kunci: airtanah, analisis bibliometrik, Bibliometrix VOSviewerAbstract - The needs of the community related to groundwater are increasing. Assessing groundwater vulnerability is one way to protect groundwater resources from being polluted. This study aims to review systematic literature and bibliometric analysis for groundwater vulnerability research in Indonesia using the Scopus database. The parameters were analyzed through several publications, journals/proceedings, keywords and total citations. The search results found 26 articles from 74 authors in the range 2013-2021. Popular keywords that emerged in research include groundwater pollution, groundwater vulnerability, groundwater resources, aquifers, and groundwater. Data processing and visualization using the bibliometric and VOSviewer applications. The results of the analysis compiled a thematic map that describes 4 quadrants based on density and centrality levels. This thematic map is expected to be a reference for groundwater vulnerability research in Indonesia.Keywords: groundwater, bibliometric analysis, Bibliometrix VOSviewer

ABSTRAK - Pengamanan kegiatan penambangan bawah tanah dilakukan bertujuan untuk menjaga stabilitas dan keamanan lubang bukaan terowongan dari reruntuhan batuan. Pengamanan kegiatan penambangan bawah tanah diperlukan kajian rekayasa geologi teknik seperti pemetaan lapangan, perhitungan Rock Mass Rating (RMR), tinggi bukaan terowongan bawah tanah, waktu runtuh (stand-up time), serta dimensi keruntuhan (beban runtuh, tinggi runtuh, dan beban luas atap). Penelitian ini menggunakan data kondisi geologi secara umum, pemetaan lapangan, perhitungan Rock Mass Rating (RMR), waktu runtuh (stand-up time), dimensi keruntuhan (beban runtuh, tinggi runtuh, dan beban luas atap). Kondisi geologi secara umum di daerah produksi CBT_1106_RMU_NTH dan CBT_1106_RMU_STH berupa batuan porfiritik andesit dengan dominan mineral kuarsa, memiliki jenis tekstur kuarsa crusiform, terdapat beberapa kekar menerus dengan panjang 1-3 m yang terisi dengan mineral hard filling lebar 1-5 mm, kekuatan batuan termasuk medium strong, sebagian teralterasi oleh mineral silika. Nilai RMR untuk daerah CBT_1106_RMU_NTH lebih tinggi dibandingkan CBT_1106_RMU_STH karena adanya pengaruh kondisi air tanah dengan tingkat pelapukan yang berbeda. Waktu runtuh daerah CBT_1106_RMU_NTH dapat bertahan lebih lama dibandingkan CBT_1106_RMU_STH karena daerah tersebut lebih stabil. Dimensi keruntuhan CBT_1106_RMU_NTH lebih pendek dan lebih ringan dibandingkan daerah CBT_1106_RMU_STH. Penelitian ini memberikan rekomendasi tinggi bukaan efektif tanpa penguatan.Kata kunci: geologi teknik, RMR, waktu runtuh, tinggi runtuh, beban runtuh. ABSTRACT - Securing underground mining activities is done purposely to maintain the stability and safety of underground mining openings from rock debris. Securing underground mining activities requires geological engineering studies such as field mapping, calculation of Rock Mass Rating (RMR), underground tunnel height, stand-up time, and collapse dimensions (collapse load, collapse height, and roof area load). This study uses data on general geological conditions, field mapping, calculation of Rock Mass Rating (RMR), stand-up time, collapse dimensions (collapse load, collapse height, and roof area load). The general geological conditions in the CBT_1106_RMU_NTH and CBT_1106_RMU_STH production areas are porphyritic andesitic rocks with dominant quartz minerals, have a crusiform quartz texture type, there are several continuous joints with a length of 1-3 m filled with hard filling minerals 1-5 mm wide, rock strength including medium strong, partially altered by silica minerals. The RMR value for the CBT_1106_RMU_NTH area is higher than CBT_1106_RMU_STH due to the influence of groundwater conditions with different levels of weathering. The collapse time for the CBT_1106_RMU_NTH area can last longer than CBT_1106_RMU_STH because this area is more stable. The CBT_1106_RMU_NTH collapse dimension is shorter and lighter than the CBT_1106_RMU_STH region. This study provides a high recommendation of effective aperture without reinforcement.Keywords: engineering geology, RMR, stand-up time, collapse height, collapse load