Febri Hirnawan
Universitas Padjadjaran

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A Measure of Intense in West and Central Java Through Manifestation of River Basin Morphometry Development on Quaternary Volcanic Deposits Hirnawan, Febri
Indonesian Journal on Geoscience Vol 4, No 4 (2009)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1781.335 KB) | DOI: 10.17014/ijog.v4i4.88

Abstract

DOI: 10.17014/ijog.v4i4.88Indications exhibiting active tectonic movements in Java occur in many places, characterized by unstable regions, such as active faults, earthquakes, volcanic eruptions, etc. The results of researches conducted at several areas in West and Central Java on tectonic morphometry developments of river basins both in Quaternary deposits and Tertiary sediments exhibit a degree of active tectonic intensity. Such the researches are very important regarding to the spatial development design that is related to a region of active tectonism that should be well understood by planners for decision making mainly through comprehensive approach, in which the phenomena involved explaining the characteristics of the region as part of an active plate margin. Statistic approach as the chosen methodology had been utilized to gain meaningful conclusions through the verification of hypotheses, which are based on valid and reliable tested data obtained from the fields and satellite imagery. Results of regression-correlation tests between azimuths of river segment and lineaments in both chronostratigraphic systems mentioned earlier are significant with several large values of correlation coefficients r of no less than 0.9. On the other hand, results of t-tests are not a significant difference of means of bifurcation ratio (Rb) and drainage density (Dd) from many to river basins. The results of all tests have verified the effect of active tectonic control on the morphometry development process regarding to river segments and density of drainage patterns development in Tertiary and Quaternary deposits.
Similarity of Drainage Basin Morphometry Development on Quarternary and Tertiary Rock Deposits as a Measure of Neotectonic Intensity in Bumiayu Area, Central Java Hirnawan, Febri
JURNAL RISET GEOLOGI DAN PERTAMBANGAN Vol 19, No 1 (2009)
Publisher : Indonesian Institute of Sciences

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (2023.674 KB) | DOI: 10.14203/risetgeotam2009.v19.18

Abstract

ABSTRAK Batuan Tersier dan endapan volkanik Kuarter yang tidak selaras di atasnya sebagai produk Gunung Slamet, yang terdeformasi, menentukan perkembangan morfometri Daerah  Aliran Sungai Pemali di Kecamatan Bumiayu, Jawa Tengah dan sekitarnya. Dalam riset ini, morfometri  di daerah penyebaran kedua satuan batuan itu dipelajari sebagai gejala morfometri tektonik dalam artian pengaruh neotektonisme, yang mengakibatkan kerusakan infrastruktur.Hasil-hasil uji regresi-korelasi antara azimuth segmen sungai dan kelurusan di kedua satuan batuan yang berlainan usia tersebut adalah signifikan, yang menunjukkan nilai-nilai tinggi dari koefisien korelasi masing-masing r1 = 0.999 dan  r2 = 0.998, yang memberikan kesimpulan kuat bahwa tektonik sangat berperan dalam mengontrol proses perkembangan morfometri.Selanjutnya, uji beda rata-rata terhadap kedua variabel itu dan juga terhadap nisbah percabangan sungai (Rb) dan kerapatan pengaliran (Dd) dari dua DAS yang berkembang pada masing-masing satuan batuan tidak berbeda secara signifikan. Hasil uji ini memberikan kesimpulan bahwa perkembangan DAS tidak dipengaruhi oleh jenis batuan tetapi lebih oleh pengaruh pola deformasi. Fenomena ini menunjukkan bahwa tektonik masa kini aktif sehingga menghasilkan pola-pola kekar yang sama pada Formasi Halang dan Formasi Kumbang,  dengan  pada  endapan  volkanik sama pada Formasi Halang dan FormasiKumbang, dengan pada endapan volkanik Kuarter, yang secara menerus deformasi itu telah memotong bidang ketidakselarasan antara kedua formasi dan endapan Kuarter tersebut.
Gold mineralization in the Neo-Tectonic Region of Honje Formation and Cipacar Formation Usman, Dudi Nasrudin; Sulaksana, Nana; Hirnawan, Febri; Haryanto, Iyan
Journal of Geoscience, Engineering, Environment, and Technology Vol 3 No 4 (2018): JGEET Vol 03 No 04 : December (2018)
Publisher : UIR PRESS

Show Abstract | Download Original | Original Source | Check in Google Scholar | DOI: 10.24273/jgeet.2018.3.4.1852

Abstract

The gold ore mineralization region is a zone of mineralization which is inseparable from the role of geological structures, one of which is fracture. The Cibaliung and surrounding areas are epithermal gold mineralization zones, in this region there are two main mineralized zones, namely Cibitung Zone and Cikoneng Zone. It has almost the same characteristics where the fractures formed are quite large so that it influences the class of rock mass, but the other side is the presence of many fractures which make it easier for scattered mineralization to fill the fracture so that the formed vein is thick enough. This study aims to analyze the relationship of Rock Mass Rating (RMR) and Rocks Quality Design (RQD) to tectonic movements in the region to prove the neo-tectonic phenomena in the Honje Formation and Cipacar Formation using surface mapping methods. The methods used are rock type mapping, rock structure mapping, mapping and RQD measurements, rock descriptions and rock sample collection. All the data obtained are then verified and validated before processing and statistical tests. Statistical tests are carried out to ensure an analysis with a basis that is recognized by all parties. Both formations above have different ages, which is for the Honje Formation (Andesite Lava) with the final Miocene age and Cipacar Formation (tuff) at the age of Pleistocene. The findings of this study are the two formations measured by RQD and RMR on rock cracks and surrounding conditions; the RMR observation station made around 125 points in the Honje Formation and 117 points in the Cipacar Formation. The R2 value of the RMR value of the Honje Formation and the Cipacar Formation shows a positive relationship of 67%; The biggest RMR value is in Tuff rock. In addition, the relation between RMR Andesite Lava Value and RMR Tuff Value is done with T-Test between Andesite Lava and Tuff where the result shows no difference of mean between RMR Andesite Lava and RMR Tuff Value. Therefore, the tectonic processes that occur in the Honor Andesite Lava Unit of Honje Formation with the preceding position are formed, and the older age at the end of the Miocene age that is blocked by the field of unconformity experienced Continuity on Cipacar Formation Tuff Unit with the upper position that is formed after Honje Formation and younger age in Pleistocene. The continuation of the tectonic process proves the existence of active tectonic activity better known as Neo-tectonic.
A Measure of Intense in West and Central Java Through Manifestation of River Basin Morphometry Development on Quaternary Volcanic Deposits Hirnawan, Febri
Indonesian Journal on Geoscience Vol 4, No 4 (2009)
Publisher : Geological Agency

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (1781.335 KB) | DOI: 10.17014/ijog.4.4.285-300

Abstract

DOI: 10.17014/ijog.v4i4.88Indications exhibiting active tectonic movements in Java occur in many places, characterized by unstable regions, such as active faults, earthquakes, volcanic eruptions, etc. The results of researches conducted at several areas in West and Central Java on tectonic morphometry developments of river basins both in Quaternary deposits and Tertiary sediments exhibit a degree of active tectonic intensity. Such the researches are very important regarding to the spatial development design that is related to a region of active tectonism that should be well understood by planners for decision making mainly through comprehensive approach, in which the phenomena involved explaining the characteristics of the region as part of an active plate margin. Statistic approach as the chosen methodology had been utilized to gain meaningful conclusions through the verification of hypotheses, which are based on valid and reliable tested data obtained from the fields and satellite imagery. Results of regression-correlation tests between azimuths of river segment and lineaments in both chronostratigraphic systems mentioned earlier are significant with several large values of correlation coefficients r of no less than 0.9. On the other hand, results of t-tests are not a significant difference of means of bifurcation ratio (Rb) and drainage density (Dd) from many to river basins. The results of all tests have verified the effect of active tectonic control on the morphometry development process regarding to river segments and density of drainage patterns development in Tertiary and Quaternary deposits.
Identifikasi prospek panas bumi berdasarkan Fault and Fracture Density (FFD): Studi kasus Gunung Patuha, Jawa Barat Bujung, Cyrke A.N.; Singaribun, Alamta; Muslim, Dicky; Hirnawan, Febri; Sudrajat, Adjat
Jurnal Lingkungan dan Bencana Geologi Vol 2, No 1 (2011)
Publisher : Badan Geologi

Show Abstract | Download Original | Original Source | Check in Google Scholar | Full PDF (4749.663 KB) | DOI: 10.34126/jlbg.v2i1.17

Abstract

SARIPenelitian ini bertujuan untuk mengidentifikasi struktur permukaan daerah panas bumi berdasarkan densitas kelurusan, anomali magnetik, dan manifestasi panas bumi di permukaan. Struktur permukaan dianalisis melalui kerapatan lineament di permukaan dengan metode FFD. Lineament ini diasumsikan berasosiasi dengan fracture atau fault di daerah panas bumi yang umumnya tertutup oleh manifestasi permukaan sehingga sulit teridentifikasi. Fault dan fracture ini diasumsikan sebagai bidang lemah yang menjadi jalur pergerakan fluida termal sehingga dapat menjadi petunjuk bagi lokasi daerah permeabel atau reservoir. Berdasarkan metoda FFD yang dikompilasikan dengan data geomagnetik,diketahui bahwa daerah prospek panas bumi berada di daerah Cibuni, Kawah Putih-Kawah Ciwidey.Kata kunci: struktur, lineament, FFD, Panas bumiABSTRACTThis research aims to identify the surface structures of geothermal area based on lineament density, magnetic anomaly and surface manifestation. The surface structures were analyzed through the density of lineaments on the surface with FFD method. The lineaments are assumed associated with fractures or faults found in geothermal areas those are generally covered by surface manifestation which are difficult to be identified. These faults and fractures were assumed as weak plane that act as fluid thermal movement, thereby it can be used as guidance for the location of permeable area or a reservoir. Based on FFD method which was compiled with magnetic data, it is known that the prospect of geothermal area is located at Cibuni, Kawah Putih-Kawah Ciwidey.Keywords: structure, lineament, FFD, Geothermal
KESTABILAN LERENG TAMBANG TERBUKA BATUBARA DI DAERAH DESA PURWAJAYA, KECAMATAN LOAJANAN, KABUPATEN KUTAI KARTANEGARA, PROVINSI KALIMANTAN TIMUR Sulaeman, Sulaeman; Sophian, Rd. Ivan; Dipatunggoro, Geni; Hirnawan, Febri
Buletin Sumber Daya Geologi Vol 9, No 2 (2014): Buletin Sumber Daya Geologi
Publisher : Buletin Sumber Daya Geologi

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Abstract

Pertambangan batubara pada 10 tahun terakhir mengalami peningkatan. Kegiatan pertambangan tidak terlepas dari kegiatan eksplorasi dan eksploitasi. Tambang terbuka maupun tambang bawah permukaan erat hubungannya dengan kajian geoteknik dan menjadi persyaratan dalam mengajukan izin kegiatan penambangan. Lokasi administrasi daerah penelitian terletak di daerah Desa Purwajaya, Kecamatan Loajanan, Kabupaten Kutai Kartanegara, Provinsi Kalimantan Timur. Dalam kegiatan di lapangan dilakukan pemetaan geologi teknik dan pengeboran geoteknik. Dari hasil kegiatan tersebut data diolah dilaboratorium dan menghasilkan sifat fisik dan mekanik tanah dan batuan untuk dapat mengetahui kekuatan massa batuan. Analisis laboratorium menghasilkan data sifat fisik dan mekanik tanah dan batuan. Hasil analisis tersebut digabungkan dengan hasil deskripsi pengeboran geoteknik yang kemudiandigunakan untuk menentukan kekuatan massa batuan (RMR) di setiap titik bor. Pada titik bor GT 01 dengan RMR kisaran 37 termasuk dalam kelas IV (poor rock) dan kelas III (fair rock). Titik bor GT 02 dengan kisaran RMR 35 termasuk kelas IV (poor rock) dan 68 untuk kelas II (good rock). Titik bor GT 03 dengan kisaran RMR 30 termasuk kelas IV (poor rock) dan 73 untuk kelas II (good rock). Simulasi kestabilan lereng dilakukan dengan menggunakan data hasil analisis laboratorium pada kedalaman dan sudut lereng tertentu dan menghasilkan nilai FS 1,265 untuk highwall dan 1,311 untuk lowwall.
RESPONSE OF STABLE OVERALL SLOPE GEOMETRY OF OPEN PIT COAL MINE IN WARUKIN FORMATION TO DEWATERING AND PEAK GROUND SEISMIC IN SOUTH KALIMANTAN, INDONESIA Oscar, Agus W; Muslim M.Sc., Ir. H. Dicky; Sulaksana, Nana; Hirnawan, Febri
Buletin Sumber Daya Geologi Vol 11, No 1 (2016): Buletin Sumber Daya Geologi
Publisher : Buletin Sumber Daya Geologi

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Understanding of the response of the mine slope stability is very important regarding the safety of life and investment / productivity / environment, as anticipation of landslide prevention based on the latest research. Mine slope behavior previously discussed widely in terms of the response due to dewatering and seismic (Peak Ground Acceleration) as well through verification. This paper aims to obtain a broad dimension of design criteria that are not only unstable slopes, but the slope is stable under various conditions of the rock mass saturation (dewatering) and seismic condition. Response of slope stability per geotechnical rocks unit from different formations or any engineering formation as a result of environmental influences, for example, the same quake, will be different. This means that the geometry of the same slope in other formation will have different stability conditions (safety factor of the slope) due to the same seismic acceleration. This is also similar due to dewatering. The method used for this study is the deductive-probabilistic method with a hypothetical verification approach. The Standard statistical analysis is used to test the data normality and homogeneity, average and independent differences, as well as regression-correlation test. The research results show that dewatering activitycan decrease ground water level (GWL/MAT) of the slope, so the durability of sliding along the sliding plane is reduced (increasing slope safety factor). At the same time earthquake reduces shear strength and increases driving force, so the safety factor of the slope suddenly downs. Slope stability decreased due to the earthquake, but dewatering improves slope stability. Thus, the slope in dewatering conditions will be kept stable through simulation to anticipate earthquake.
PENDUGAAN NILAI TAHANAN JENIS BATUAN UNTUK MENGETAHUI STRUKTUR GEOLOGI PADA ENDAPAN VULKANIK DI KEC. PADARINCANG, PROVINSI BANTEN. Endyana, Cipta; Hirnawan, Febri; Hendrawan, Hendrawan; Mardiana, Undang
Buletin Sumber Daya Geologi Vol 6, No 3 (2011): Buletin Sumber Daya Geologi
Publisher : Buletin Sumber Daya Geologi

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Pendugaan nilai-nilai tahanan jenis batuan menggunakan metode Schlumberger merupakan pendekatan yang efektif untuk menduga kondisi batuan bawah permukaan. Penggunaan teknik interpolasi danpengelompokkan nilai tahanan jenis lebih lanjut dapat menafsirkan kontinuitas lateral jenis batuan dan struktur geologi.Pengolahan dan pengujian secara statistik  analisis regresi berganda pada nilai tahananjenis menghasilkan enam jenis kelompok batuan, yaitu: Breksi grain supported, Tuf Lapili, Tuf Kasar, Breksi grain supported, tuf lapili, breksi matrix supported. Hasil uji korelasi pada karakter tahanan jenis keenam kelompok batuan tersebut ditemukan bahwa ada tiga sumber material yang berbeda pada saat pengendapannya. Material endapan diyakini berasal dari Gunung Parakasak, Gunung Karang dan Gunung Kamuning. Kesamaan nilai tahanan jenis pada pola berarah barat-timur menunjukkan kesamaan litologi, sedangkan kesamaan nilai tahanan jenis pada pola dengan arah utara-selatan menunjukkan nilai kontras tahanan jenis yang disebabkan oleh dua jenis sesar berarah relatif barat-timur dengan mekanisme yang berbeda.
Pola Deformasi (Deformation Pattern) Mineralisasi Emas Sulfida Rendah di Zona Neo-Tektonik Selat Sunda Usman, Dudi Nasrudin; Sulaksana, Nana; Hirnawan, Febri; Haryanto, Iyan
PROMINE Vol 6 No 1 (2018): PROMINE
Publisher : Jurusan Teknik Pertambangan, Fakultas Teknik, Universitas Bangka Belitung

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The Sunda Strait is one of the zones of the Eurasian plate encounters with fairly active Indian plates. This can be seen based on volcanic activity that occurred in the region of Mount Krakatau. But there are unique things that are important to learn is tectonic movement with geological forces that work to produce cracks in rocks, the formation of volcanoes and cracks that occur produce mineralized zones, especially in the Formation of Honje and Formation Cipacar and more widely known as Bayah Dome. The presence of mineralization of the Honje Formation and Cipacar Formation is particularly located in the District of Cimanggu, Mangku Alam Village, the existence of gold mining activities proves that the mineralization of the region has the potential of economy. The presence of mineralization will not be separated from the presence of rock fractures in the two formations that have different geological age of the Late Miocene and Plistocene. Both formations are hindered by the presence of unconformity fields. This study aims to prove the extent of tectonic activity occurring in the Honje Formation with the final Miocene age forwarded to the Cipacar Formation even though obstructed by the field of nonconformity with the results of field data processing based on the value of RMR and RQD value. Both parameters are also studied to determine the extent to which the RQD value determines the magnitude of the grade value of Gold (Au). The distribution of RMR value and rock RQD value is taken from 2 different rock units, ie, andesite rock units in Honje Formation and tuff rock units in Cipacar Formation, based on the data distribution around 125 RMR observation points and 117 RQD observation points in the field are processed by using method test the average difference of the two parameters from 2 different rock units. In addition, the RQD value was correlated to the high level of gold content using correlation regression test of 78 data content and RQD value. Results of processing and discussion of data indicate that between the value of RMR in andesit unit and tuff unit there is no difference in value means H0 accepted by tcount = 0.556 <ttable = 1.995, as well as the difference test average RQD value where the results show that there is no difference between the average value of RQD andesite rock units in Honje Formation and tuff rock units in Cipacar Formation with tcount = 1.714 <ttable = 1.995, based on the results of data processing it can be explained that the tectonic activity in Honje Formation with the final Miocene age is forwarded to Cipacar Formation even if obstructed the field of dissonance means that tectonic activity of the region is inferred as neotectonic activity of West Java. In addition, one more thing that can be concluded that the relationship of RQD with Gold content (Au) based on statistical test the greater the value of RQD then the value of gold content (Au) the greater the test results regression correlation value PValue (Significance) = 0.013 with the equation y = -0.715x + 75.882 value R2 42.39%. Because Significance value> 0.05 then H0 DENIED, so H1 accepted, where the higher the value of the Big Au content then the RQD Value the greater.