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Karakteristik Sistem Akuifer pada Formasi Endapan Permukaan di Daerah Sei Mati Kota Medan Berdasarkan Metode Geolistrik 2D Mutaqin, Deden Zaenudin; Mardiana, Undang; Alfadli, Muhammad Kurniawan; Mohammad, Febriwan; Yuniardi, Yuyun; Nur, Andi Agus
BERKALA SAINSTEK Vol 8 No 4 (2020)
Publisher : Universitas Jember

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.19184/bst.v8i4.18102

Abstract

Daerah Sei mati memiliki potensi sumber daya air yang baik, dikarenakan daerah yang termasuk Cekungan Air tanah Medan. Penelitian ini bertujuan untuk mengetahui potensi airtanah dengan menggunakan metode geolistrik 2D dengan konfigurasi wenner-schulumberger. Hasil penelitian menunjukan terdapat 2 lapisan akuifer yaitu akuifer dangkal dan dalam. Lapisan akifer dangkal berada pada kedalaman berkisar antara 0 – 50 meter, membentuk pola channel-channel yang menunjukan endapan fluvial dengan nilai tahanan jenis antara 5 Ω.m - 10 Ω.m, dengan litologi pasir lempungan, namun dibeberapa tempat dijumpai channel lempung yang bersifat akuiklud (tidak dapat menyimpan air). Lapisan akuifer dalam muncul pada kedalaman 50 meter hingga 100 meter dengan litologi pasir.
ANALYSIS OF LANDSLIDE CAUSES IN NANGGERANG VILLAGE, SUKASARI SUB DISTRICT, SUMEDANG REGENCY THROUGH IDENTIFICATION LANDSLIDE SLOPE MATERIAL CHARACTERISTICS Aruan, Immanuel Hareanto; Yuniardi, Yuyun; Khoirullah, Nur; Sophian, Raden Irvan
Journal of Geological Sciences and Applied Geology Vol 8, No 1 (2024): Journal of Geological sciences and Applied Geology
Publisher : Faculty of Geological Engineering, Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/gsag.v8i1.56627

Abstract

On February 3, 2024, a landslide occurred in Nanggerang Village, Sukasari District, Sumedang Regency, West Java Province. The landslide took place on the slopes of local farmland. This event was investigated through an analysis of the characteristics of the landslide material collected immediately after the landslide to determine its cause and mechanism. The landslide slope was divided into three units based on the type and degree of weathering: topsoil (OH), silt soil (MH), and weathered tuff rock. Three undisturbed samples were used in laboratory experiment to determine the materials’ physical characteristics. The physical characteristics of the two soil units, which included silt-sized grains, a specific gravity of roughly 2.6, a unit weight ranging from 21 to 45 kN/m3, and a plasticity index of 16 to 20, were not substantially different, according to the results of the laboratory tests. For the tuff rock, the unit weight was 17.31, water content 48.8, and specific gravity 22.7. The laboratory test results, and studio analysis found that the high water content in the soil due to rainfall caused the two soil units to exceed their liquid limit, resulting in a translational (arc) landslide. The presence of clay minerals due to weathering acted as a catalyst for the landslide. The addition of water from heavy rainfall made the material more fluid, changing the type of landslide to an earth flow.
FASIES BATUBARA FORMASI WARUKIN BERDASARKAN ANALISIS CORE DI DAERAH SUNGAI DIDI, KECAMATAN DUSUN TIMUR, KABUPATEN BARITO TIMUR KALIMANTAN TENGAH Yuniardi, Yuyun
Bulletin of Scientific Contribution Vol 3, No 2 (2005): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (472.644 KB) | DOI: 10.24198/bsc.v3i2.7451

Abstract

Research area layed on Sungai Didi, Dusun Timur District, Barito Timur Residence, KalimantanTengah Province. The border in geographically, 1150 11’ 1,22” – 1150 12’ 35” East Longitude and 20 2’27,93” – 20 3’ 28,74” South Latitude.Geology of research area consisted of two rock units, there were sandstone unit and claystone unit.Claystone unit consisted of claystone with alternated by coal, and then sandstone unit consisted ofsandstone which have coarse grain to fine grain. Both of those units were related with WarukinFormation, where formed at fluviatil environment with Middle Miosen of age.Research area facies would have four kinds and made into the group, there were MS (massivesandstone), FS (fining upward sandstone), CL (claystone) and Co (coal). Facies model which made haveconsisted of MS facies in lowers followed with FS facies, and then CL facies and Co in uppers.Keywords : Warukin Formation, Fluviatil, Facies
DEBIT ALIRAN (WATER YIELD) SUB-DAS CIGUMENTONG DAN CIMULU SUB-DAS CITARIK BAGIAN PALING HULU Haryanto, Edi Tri; Nur, Andi Agus; Haryanto, Iyan; Yuniardi, Yuyun
Bulletin of Scientific Contribution Vol 13, No 2 (2015): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (557.577 KB) | DOI: 10.24198/bsc.v13i2.8397

Abstract

Cigumentong and Cimulu sub-watersheds are growing at vokanik denudasional landform with geological formations of undeferienciated old volcanic product consists of tuff , breccia and lava of the uppermost of Citarik Sub-Catchment . Based on the order system according to Strahlaar both river is a river -order 4 , with the land cover of relatively dense forest vegetation with an area of 552 Ha respectively and 606 Ha . This study aims to investigate the flow discharge characteristics of the two rivers by measuring daily and daily rainfall during the period 20 December 2014 through to March 2015, or for 71 days . The research result is fluctuations in flow discharge rate between the River Cigumentong and Cimulu tend to be similar . Inlfiltration coefficient of Cimulu sub-watersheed was slightly larger (0.54)than that was Cigumentong sub-watersheed (0.53), with the infiltration thickness of 695 mm for Cimulu and 577 mm for Cigumentong. Runoff coefficient Cimulu sub-watersheed is larger (0.44) than Cigumentong (0.37) .
POTENSI DAN KUALITAS BATUBARA DAERAH LIPON-GENDANG KECAMATAN SUNGAI DURIAN, KABUPATEN KOTABARU, KALIMANTAN SELATAN -, Yuyun Yuniardi
Bulletin of Scientific Contribution Vol 4, No 1 (2006): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (622.959 KB) | DOI: 10.24198/bsc.v4i1.8113

Abstract

Location of research area was in Lipon-Gendang, Sungai Durian District, Kotabaru Residence, Kalimantan Selatan Province, there were into Tanjung Formation which had Coal Bearing Formation.Focused of subject this research was quality and potential of coal, and those have been coal distribution from several coal seam, resources prediction with used USGS methode, and analysis quality of coal from field research sample.There had been potential enough for coal from result of research. And that proved with have four seam were thickly between 0,2 – 3 m, and predicted of resources were 1.403.550 ton, and then quality of coal : calory average 5419,46 cal/gr and sulfur average 1,47 %.
STRATIGRAFI VULKANIK DI LERENG UTARA GUNUNG TANGKUBAN PARAHU, DAERAH CISALAK, KABUPATEN SUBANG, PROVINSI JAWA BARAT Yuniardi, Yuyun; Hendarmawan, .; Isnaniawardhani, Vijaya; Abdurrokhim, .; Ridwan, Panji
Bulletin of Scientific Contribution Vol 17, No 3 (2019): Bulletin of Scientific Contribution : GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2197.751 KB) | DOI: 10.24198/bsc.v17i3.24985

Abstract

AbstrakGunung Tangkuban Parahu adalah gunung api aktif di Provinsi Jawa Barat yang merupakan  fase termuda dari kelanjutan sistem vulkanisme Sunda-Tangkuban Parahu yang memiliki sejarah geologi yang cukup rumit dan komplek, khususnya daerah Cisalak dan sekitarnaya, Kabupaten Subang. Metode Fasies Gunungapi dapat digunakan untuk merekonstruksi peristiwa erupsi yang terjadi masa lampau dan juga dapat digunakan untuk memprediksi arah aliran apabila terjadi erupsi berikutnya. Stratigrafi vulkanik daerah penelitian dapat dibagi menjadi enam satuan yang diurutkan dari muda ke tua, yaitu: Aliran Piroklastik 1  Bukittunggul (Ba1) Holosen; Jatuhan Piroklastik Tangkuban Parahu (Tj) Holosen; Aliran Piroklastik Tangkuban Parahu (Ta) Holosen; Aliran Piroklastik 2 Bukittunggul (Ba2) Plistosen awal; Aliran Lava Bukittunggul (Bl) Plistosen awal; dan Aliran Lava Sunda (Sl) Plistosen tengah. Setelah dilakukan analisis fasies diperoleh fasies dengan endapan paling muda yang memiliki material berupa konglomerat dan fasies debris flow, pada fase selanjutnya didapatkan fasies endapan jatuhan piroklastik, kemudian dilanjutkan dengan fasies aliran prioklastik atau ignimbrit, dan fasies berikutnya adalah berupa block dan ash deposit, serta fasies terakhir dengan meterial tertua yang berlitologikan lava adalah fasies lava koheren. Dampak erupsi berupa aliran lahar, awan panas, dan material jatuhan yang terjadi di masa lalu masih sangat mungkin terjadi pada masa yang akan datang. Katakunci: Tangkuban Parahu, Fasies Gunungapi, Erupsi. AbstractTangkuban Parahu Volcano is an active volcano in West Java Province which is the youngest phase of the continuation of the Sunda-Tangkuban Parahu volcanism system which has a fairly complex and complex geological history, especially the Cisalak and surrounding areas, Subang Regency. The Volcanic Facies Method can be used to reconstruct eruption events that have occurred in the past and can also be used to predict the direction of flow when the next eruption occurs. The volcanic stratigraphy of the study area can be divided into six units which are sorted from young to old, namely: Pyroclastic Flow 1 Bukittunggul (Ba1) Holocene; Holocene Tangkuban Parahu (Tj) Pyroclastic Fall; Pyroclastic Flow Tangkuban Parahu (Ta) Holocene; Bukittunggul 2 Pyroclastic Flow (Ba2) Early Plistocene; Bukittunggul Lava Flow (Bl) Early Plistocene; and Sunda Lava Flow (SL) Middle Plistocene. After facies analysis, facies was obtained with the youngest sediment which had material in the form of conglomerates and debris flow facies, in the next phase obtained facies of pyroclastic fall deposits, then proceed with prioclastic flow facies or ignimbrite, and the next facies were blocks and ash deposits, and facies the last with the oldest meterial lava is the coherent lava facies. The impact of the eruption in the form of lava flow, hot clouds, and falling material that occurred in the past is still very likely to occur in the future. Keywords: Tangkuban Parahu, Volcano Facies, Eruption.
PENINGKATAN AKURASI PERHITUNGAN CADANGAN BATUBARA DI WILAYAH SEPARI - KALIMANTAN TIMUR BERDASARKAN DETEKSI KEMIRINGAN LUBANG BOR DENGAN SENSOR GYROSCOPE-ACCELEROMETER-HEADING DIJITAL Firmansyah, Gilang; Sukiyah, Emi; Yuniardi, Yuyun; Mardiana, Undang
Bulletin of Scientific Contribution Vol 14, No 1 (2016): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1129.941 KB) | DOI: 10.24198/bsc.v14i1.9786

Abstract

Penaksiran sumber daya dalam suatu proses penambangan batubara didapatkan melalui perhitungan dan analisis data eksplorasi detil. Data ini diperoleh dengan metode pemboran dan pemetaan geologi. Penaksiran sumber daya dilakukan untuk mengetahui taksiran jumlah tonase sumber daya batubara. Hasil taksiran selanjutnya digunakan untuk perhitungan stripping ratio pada lahan tersebut untuk mengetahui keekonomian bahan tambang. Hasil yang diperoleh dapat  menentukan kelayakan suatu tambang untuk di eksploitasi. Pada proses pengeboran terdapat istilah borehole deviation, yaitu deviasi atau simpangan miring dari suatu target lubang bor. Selama ini, pengeboran tegak lurus selalu dinyatakan memiliki kemiringan 90°. Asumsi tersebut sebenarnya tidak tepat. Kemiringan lubang bor yang dinyatakan tegak lurus ternyata memiliki nilai bervariasi. Oleh karena itu, survei kemiringan lubang bor perlu dilakukan untuk mengetahui kemiringian lubang bor secara akurat. Nilai dip dan azimut lubang bor turut berperan sebagai parameter penting dalam meningkatkan akurasi perhitungan cadangan. Berdasarkan hasil uji coba terhadap penggunaan sensor gyroscope-accelerometer-heading dijital pada pengeboran eksplorasi di wilayah Separi diperoleh adanya peningkatan hasil perhitungan cadangan batubara.
GEOMETRI AKUIFER BERDASARKAN DATA GEOLISTRIK DAN SUMUR PEMBORAN DI DAERAH JASINGA, KECAMATAN JASINGA, KABUPATEN BOGOR, JAWA BARAT Mohammad, Febriwan; Mardiana, Undang; Yuniardi, Yuyun; Alfadli, Muhammad Kurniawan
Bulletin of Scientific Contribution Vol 15, No 3 (2017): Bulletin of Scientific Contribution:GEOLOGY
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (598.522 KB) | DOI: 10.24198/bsc.v15i3.14700

Abstract

SARI            Daerah penelitian secara geografis terletak pada  106° 26’ 45” BT sampai 106° 29’ 15” BT dan -6° 26’ 00” LS sampai  -6° 28’ 30” LS. Secara administratif daerah penelitian berada di Desa Cikopomayak dan sekitarnya, Kecamatan Jasinga, Kabupaten Bogor, Provinsi Jawa Barat. Daerah penelitian terbagi menjadi 2 satuan batuan yaitu Satuan Batulanau dan Intrusi Andesit. Pengukuran geolistrik dan sumur pemboran digunakan untuk mengetahui kondisi geologi bawah permukaan secara vertikal maupun lateral. Daerah penelitian memiliki tiga kelompok nilai resistivitas dan litologi, yaitu batuan dengan nilai resistivitas rendah (0 – 60 Ω.m) dengan litologi batulempung – serpih dan batulanau, resistivitas menengah (61 – 130 Ω.m) dengan litologi batulempung pasiran, batupasir sedang, dan batupasir kasar, dan resistivitas tinggi (131 – 180 Ω.m) dengan litologi batupasir halus, batulempung pasiran, dan andesit. Keberadaan lapisan akuifer dibuktikan dengan adanya lapisan batupasir sedang – batupasir kasar pada kedalaman 10 dan kedalaman 20 meter dari sumur pemboran. Dari korelasi data geolistrik dan sumur pemboran,  dibuat penampang sistem akuifer yang melewati daerah penelitian yang selanjutnya di modelkan ke dalam diagram pagar geometri akuifer. Berdasarkan model geometri akuifer, daerah penelitian terbagi menjadi tiga jenis akuifer yaitu, akuifer bebas, akuifer semi tertekan, dan akuifer tertekan.Kata Kunci : geolistrik, sumur pemboran, geometri akuifer. ABSTRACTThe research area is geographically located at 106° 26’ 45” East up to 106° 29’ 15” East and 6° 26’ 00” South up to  6° 28’ 30” South. Administratively, area of research is in the Cikopomayak, Jasinga, Bogor District, West Java Province.  The research area is  divided into two rock units, Siltstone Unit and Andesite Intrusion. Georesistivity method and well drilling used to study subsurface geology. The research area have three kind of resistivity and lithology value, that is low resistivity (0 – 60 Ω.m) with shale and siltstone lithology, medium resistivity (61 – 130 Ω.m) with sandy clay and sandstone lithology, and high resistivity (131 – 180 Ω.m) with sandstone, sandy clay, and andesit lithology.  Presence of aquifer layer proved by sandstone in well drilling at depth of 10 – 20 meters. From the georesistivity and well drilling data correlation, made a cross section of aquifer system in the research area, then modelled to fence diagram. According to geometric model of aquifer, the research area divided to three aquifer configurations, unconfined aquifer, semi confined aquifer, and confined aquifer.Keyword : resistivity, geometry aquifer
Interpretasi Kondisi Geologi Bawah Permukaan Berdasarkan Data Geofisika Magnetotellurik Daerah Blora, Provinsi Jawa Tengah YUNIARDI, YUYUN; Mardiana, Undang; Nur, Andi Agus; Mohammad, Febriwan; Alfadli, Muhammad Kurniawan
Bulletin of Scientific Contribution Vol 19, No 3 (2021): Bulletins of Scientific Contribution : Geology
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24198/bsc.v19i3.37879

Abstract

Daerah penelitian berada di Kabupaten Blora, Jawa Tengah, termasuk kedalam zona Rembang Cekungan Jawa Timur bagian Utara, dan tersusun lima Formasi yaitu; Formasi Tambakromo, Formasi Selorejo, Formasi Mundu, Formasi Ledok, Formasi Wonocolo, namun penentuan batas-batas Formasi pada daerah penelitian belum ada yang dapat menjelaskan dan gambaran struktur bawah permukaan masih kurang, oleh karena itu penelitian ini bertujuan untuk memberikan informasi tambahan mengenai penentukan batas-batas formasi serta stuktur geologi bawah permukaan yang akan diperoleh dari hasil interpretasi korelasi data lapangan dengan menggunakan metoda geofisika  Magnetotellurik. Hasil  Pengukuran Magnetotellurik pada 40 titik, berdasarkan nilai resistiviti terdapat 5 zona keterpengaruhan struktur, yaitu: zona 1, pada titik pengukuran 35-36; zona 2, pada titik pengukuran 27-33; zona 3 pada titik pengukuran 16-17; zona 4 pada titik pengukuran 9-10; dan zona 5 pada titik pengukuran1-2 permodelan berdasarkan nilai-nilai resisitiviti berdasarkan kedalaman, terdapat 5 batasformasi, yaitu: 1)Formasi Wonocolo, Ledok, Mundu, Selorejo, Tambakromo dan Alluvium, 2) Formasi Wonocolo dan Ngrayong, 3) Formasi Tuban, 4) Formasi Kujung, dan 5) Formasi Ngimbang dan Batuan dasar. Struktur Geologi yang berkembang berupa lipatan, antiklin pada titik 26-36, dan titik 02, sinklin di tengah titik-titik pengukuran, Sesar Normal yang bersifat tumbuh pada titik antara MT26-MT27dan pada titik 30, yang masuk kedalam zona struktur 2, dan sesar normal pada titik MT 09 masuk kedalam zona 02. Sesar Naik pada titik MT 02 pada zona 05.
PETROLOGI DAN PETROGRAFI SATUAN BREKSI VULKANIK DAN SATUAN TUF KASAR PADA FORMASI JAMPANG, DAERAH CIMANGGU DAN SEKITARNYA, JAWA BARAT Verdiana, Puteri Rasdita M.; Yuniardi, Yuyun; Nur, Andi Agus
Bulletin of Scientific Contribution Vol 12, No 3 (2014): Bulletin of Scientific Contribution
Publisher : Fakultas Teknik Geologi Universitas Padjadjaran

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (677.627 KB) | DOI: 10.24198/bsc.v12i3.8378

Abstract

The research area is located at Cimanggu Region, Langkaplancar and Pamarican Subdistrict, Ciamis, Tasikmalaya, and Pangandaran District, West Java Province. Geographically, research area located at coordinate 07o27’35,7768” to 07o32’35,7768” South Latitude and 108 o23’,482” to 108 o28’1,4844” East Longitude. Broad of research area is + 100 km2. According to unofficial lithostratiraphy, research area divided into five unit, that is Volcanic Breccia Unit, Coarse Tuff Unit, Carbonateous Sandstone Unit, Tuffaceous Sandstone, and Fine Tuff Unit.Petrology and petrography analysis of Volcanic Breccia Unit and Coarse Tuff Unit (Jampang Formation) are based on megascopic description of hand specimen sample and microscopic description of thin section. Volcanic Breccia Unit consist of volcanic breccia that composed by porphyry andecite-porphyry basalt clast with trachitic texture and crystal tuff as matrix, also porphyry andecite lava with trachitic texture and altered because secondary minerals (chlorite and secondary quartz) was identified at thin section. Coarse Tuff Unit consist of interbedding coarse tuff and fine tuff, but coarse tuff was dominant. Based on petrography analysis, coarse tuff is crystal tuff that composed by volcanic glass as matrix, and quartz and plagioclase as mineral fragment.