scholarly journals Karakteristik Keteknikan Sedimen Kuarter Kaitannya dengan Potensi Bahaya Geologi di Kawasan DAS Cimanuk Bagian Hilir

2020 ◽  
Vol 11 (3) ◽  
pp. 161
Author(s):  
Rifki Asrul Sani ◽  
Eko Soebowo ◽  
Armein M. Fikri ◽  
Imam A. Sadisun
Keyword(s):  
Active Faults ◽  
Flood Plain ◽  
Industrial Area ◽  
Research Area ◽  
Silty Sand ◽  
Geological Hazards ◽  
Cone Penetration ◽  
Quaternary Sediment ◽  
Sediment Classification ◽  
Clay Sediment

ABSTRAKKabupaten Indramayu yang akan dikembangkan sebagai kawasan industri didominasi oleh endapan Kuarter yang terdiri atas endapan fluvial, dataran banjir, pematang pantai, dan delta. Daerah tersebut terletak pada area dekat sesar aktif, yakni segmen sesar Baribis-Subang dengan besaran magnitudo 6,5 Mw. Penelitian di wilayah DAS Cimanuk bagian hilir Kabupaten Indramayu, Provinsi Jawa Barat bertujuan untuk mengetahui karakteristik fisik dan mekanik serta kaitannya dengan potensi bahaya geologi yang bisa terjadi. Metode yang digunakan dalam penelitian ini adalah pengamatan 4 inti bor teknik dan pola kurva sondir (10 CPTu dan 13 CPT) serta analisis laboratorium yakni ukuran butir, hydrometer, batas-batas Atterberg, dan klasifikasi sedimen. Berdasarkan pengamatan inti bor, pola kurva sondir, dan analisis laboratorium, jenis sedimen yang berkembang di daerah penelitian adalah lempung, lanau, lanau pasiran, pasir lanauan dan pasir dengan karakteristik yang spesifik. Tingkat kepadatan sedimen pasir serta tingkat konsistensi sedimen lempung bagian utara penelitian menunjukkan karakteristik yang relatif lebih lepas dan lunak dibandingkan dengan bagian selatan. Berdasarkan karakteristik keteknikan menunjukkan bahwa nilai N-SPT < 10 atau CPT/CPTu < 6.000 kPa pada sedimen pasir dan pasiran berpotensi terhadap likuefaksi dan nilai N-SPT < 4 atau CPT/CPTu < 5.000 kPa pada sedimen lempung dan lanau berpotensi terhadap amblesan. Kata kunci: bahaya geologi, Cimanuk, sedimen kuarterABSTRACTAs a future industrial area, Indramayu Regency is dominated by Quaternary sediment of fluvial, flood plain, beach ridge and deltaic sediments. The area is close to active faults, The Baribis-Subang fault segment with 6.5 Mw. This research is conducted around the lower Cimanuk catchment of Indramayu. Its aims to determine mechanical and physical characteristics related to potential geological hazards. The methods used in this research are 4 core observation, cone penetration patterns (10 CPTu and 13 CPT) and laboratory analysis such as grain size, hydrometer, Atterberg limits and sediment classification. Based on its methods, sediments that develop at the research area are clay, silt, sandy silt, silty sand and sand with specific character. Level consistency and density of clay and sand at the northern area is relatively soft and loose than the southern one. Based on engineering characteristics, the results show that NSPT < 10 or CPT/CPTu < 6,000 kPa value of sandy and sand sediment are potential against liquefaction and N-SPT < 4 or CPT/CPTu < 5,000 kPa value of silt and clay sediment are potential against subsidence. Keywords: geological hazards, Cimanuk, quarternary sediment

The behavior of a compressible silty fine sand

1999 ◽  
Vol 36 (1) ◽  
pp. 88-101 ◽  
Author(s):  
An-Bin Huang ◽  
Huai-Houh Hsu ◽  
Jia-Wei Chang
Keyword(s):  
Quartz Sand ◽  
Experimental Studies ◽  
Fine Sand ◽  
Silty Sand ◽  
Small Range ◽  
Cone Penetration ◽  
Fines Content ◽  
Cone Penetration Tests ◽  
Extensive Field ◽  
Tip Resistance

Publications associated with sands are often limited to clean (i.e., little fines content), uniform, uncemented silica or quartz sand. On the other hand, the importance of mineral content, particle shapes, as well as gradation to the behavior of sand has long been recognized. Although systematic studies of sands other than clean quartz sand have been limited, there is increasing attention being paid to sands with an appreciable fines content. Because of a major construction project, extensive field and laboratory experiments were performed on a silty fine sand from Mai-Liao, which is located on the central west coast of Taiwan. Results show that Mai-Liao Sand (MLS), a silty sand, can be significantly more compressible than clean quartz sand under static load. The particles of MLS have moderate strength, and significant crushing can be induced by triaxial shearing. As a result, MLS has low dilatancy and a relatively small range of peak friction angles. Cone penetration tests in MLS were conducted in a calibration chamber. Analyses of the data indicate that interpreting cone tip resistance in MLS using methods developed based on clean quartz sand without considering the differences of compressibility can be unrealistic. This paper documents results of the experimental studies on MLS.Key words: silty fine sand, strength, dilatancy, compressibility, crushing, in situ test.

scholarly journals The characteristics of the surface sediments in Co To island

2020 ◽  
Vol 61 (2) ◽  
pp. 33-40
Author(s):  
Chi Kim Thi Ngo ◽  
Long Van Hoang ◽  
Binh Van Phan ◽  
Tinh Nguyen Trinh ◽  
Trung Tu Do ◽  
...  
Keyword(s):  
Surface Sediments ◽  
Research Area ◽  
Field Investigation ◽  
Silty Sand ◽  
Sediment Provenance ◽  
Muddy Sand ◽  
Material Source ◽  
Sediment Distribution ◽  
Sandy Gravel ◽  
Flow Energy

552 grain size samples and 33 mineral quality defined samples have been collected in the Co To island, Tonkin Bay of Vietnam, to study the distribution and the sediment provenance. The field investigation method, the grain analysis, and the detrital composition examination method have been used to study the characteristics of the surface sediments in Co To island. The obtained results show that the surface sediments in the area consist of ten different fields, namely: sandy gravel, gravelly sand, sand, gravelly muddy sand, sand mixed gravel, muddy sand, gravelly mud mixed sand, silty sand, muddy sandy gravel, and sandy mud. The mineral component method shows that quartz is the main contain of the surface sediment (72,0÷90,6%), less rock detritus, felspat, mica, and very few of the shells. It is to confirm that the continent is the main primary material source of the study area. The distribution of the sediment is complicated. As the East-Southeast side of the research area, the sediment distribution following gravity way, coarse grain near the shore (gravel, sandy gravel,…), finer grain far off the shore (gravelly muddy sand, silty sand,…), choice level is very low. Which This is saying that the movement of sediment in the area is dominant, ; the flow energy is governed by the topography near the island and seafloor. In tMhe meanwhile, the west-northwest side, the topography of seafloor is the complicated, coarse sediment grains (gravel, sand), ); the roundness is bad, which is saying that the hydrodynamic flow there plays an important role in the sediment distribution.

scholarly journals Microzonation of Cisarua District Using Horizontal Vertical Spectral Ratio

2021 ◽  
Vol 5 (2) ◽  
pp. 88-94
Author(s):  
Elrangga Ibrahim Fattah ◽  
Keyword(s):  
Amplification Factor ◽  
Active Faults ◽  
Spectral Ratio ◽  
Dominant Frequency ◽  
Research Area ◽  
Geological Structure ◽  
Eurasian Plate ◽  
Hvsr Method ◽  
Microtremor Measurement ◽  
Tectonic System

The Bandung region is part of the framework of the Indonesian tectonic system, namely the tectonic plate meeting zone, where the Indo Autralia plate is infiltrated under the Eurasian plate in a convergent manner. The subduction process produces an effect in the form of an active fault geological structure in the Bandung area. One of these active faults is the Lembang Fault, which has a length of ± 29 kilometers and a shear acceleration of 3 to 5.5 millimeters per year. The microtremor measurement method is a passive geophysical method that utilizes natural subsurface vibrations so that it can provide dominant frequency data and amplification factors for soil layers. Based on the results of seismic susceptibility research using microtremor measurements using the HVSR method in the Lembang Fault zone in Cisarua Sub-District, it can be seen that the distribution of the dominant frequency values tends to be influenced by lithology and topography. In the research area, it is known to have a dominant frequency value that varies due to the different types of lithological units. In general, the dominant frequency ranges from 1-3 Hz because it is dominated by tuff sand and tuff pumice, and areas composed of volcanic breccias have a dominant frequency value between 3-6 Hz. Meanwhile, the amplification factor value will be influenced by rock deformation and weathering. The area that has a very high amplification factor value is in the southeast of the study area with an A0 value greater than 5. This indicates that the area is composed of a layer of thick and not dense tuff sand

scholarly journals Unique Research Area in Africa

Oryx ◽  
1974 ◽  
Vol 12 (5) ◽  
pp. 591-595
Author(s):  
Stephen P. Zilberman
Keyword(s):  
Flood Plain ◽  
Research Area ◽  
Research Station ◽  
North West ◽  
Government Research ◽  
The Government

The Sengwa Research Area in north-west Rhodesia consists of 145 square miles of uninhabited woodland and flood-plain, virtually undisturbed by man and now set aside solely for wildlife research. The author describes the government Research Station and the work going on there, particularly on warthogs, in which he took part in 1972–73.

scholarly journals Geophysical and Geotechnical Site Characterization at Lagos Central Area of Lagos State, Nigeria

2019 ◽  
Vol 6 (1) ◽  
Author(s):  
Rafiu Adegbola ◽  
Kayode Oyedele ◽  
Elizabeth Abidoye
Keyword(s):  
Central Area ◽  
Maximum Load ◽  
Shallow Foundation ◽  
Silty Sand ◽  
Cone Penetration ◽  
Engineering Structures ◽  
Shallow Subsurface ◽  
Subsurface Geology ◽  
Electrical Sounding ◽  
A Site

Introduction: Geophysical characterization refers to the collection of information associated with subsurface features. Geotechnical involves engineering structural performance studies which are used to obtain information on the physical properties of soil and rock around a site to design earthworks and foundations for proposed structures and for repair of distress to earthworks and structures caused by subsurface conditions. Aim: The study was aimed at characterizing the subsurface formations for the purpose of determining its capacity to withstand engineering structures. Materials and Methods: Geophysical techniques involving eight (8) vertical electrical sounding (VES) and Wenner array were carried out with two (2) traverses. Geotechnical investigation involving cone penetration test (CPT) was also carried out. Results: The results obtained were presented as 1D resistivity profiles and Pseudo-sections of 2-D. Three (3) geo-electric layers were delineated within the study area and these comprise of topsoil, peat or clay and silty sand. The CPT results were used in the calculation of bearing capacity using Bustamante and Gianeselli equation for pile foundations and Meyehorf equation to determine the maximum load the materials can withstand respectively. Conclusion: The shallow subsurface geology was adjudged to be mechanically unstable with low penetration resistance values up to the depth of 11m. The methods conformed and confirmed that shallow foundation was considered unsuitable for the intended engineering structure. Keywords: Meyehorf, Bustamante and Gianeselli, Subsurface, Geology, Unstable, Foundation.

scholarly journals Shallow Gas Features Based on Interpretation of Bottom Profilling Records at Topang Delta, Meranti Regency, Riau Province

2017 ◽  
Vol 31 (1) ◽  
Author(s):  
Purnomo Raharjo ◽  
Andrian Willyan Djaja ◽  
Ediar Usman
Keyword(s):  
Anaerobic Bacteria ◽  
Research Area ◽  
Reservoir Rock ◽  
Energy Research ◽  
Shallow Gas ◽  
Biogenic Gas ◽  
River Deltas ◽  
Gas Source ◽  
Cap Rock ◽  
Clay Sediment

One of the tasks in conducting a renewable energy research is finding a shallow gas contained commonly in river deltas. The location chosen is in Topang Delta,, Meranti District, Riau Province in 2015. The research was conducted by using sub-bottom profiling (SBP) method. Biogenic gas indications could be observed in the SBP records in the forms of free reflector, acoustic plumes and acoustic blanket. The shallow biogenic gas at research area is trapped in A and B sequences. Sequence A is characterized by plume gas and acoustic blanket, while B-type biogenic gas is showed by free-reflector feature of 10-15 meters depth. Sediment which does not have porocity such as old clay is required environment for anaerobic bacteria as catalyst in the formation of biogenic gas to be evolved. Old clay sediment is potential as a biogenic gas source rock afterwards migrated to a layer of sand as a reservoir rock. Some parts of biogenic gas does not appear to the surface because there have been traped in cap rock in form of young clay sediment.Keywords: Topang Delta, Biogenic Gas, free reflector, acoustic plumes, acoustic blanket Salah satu tugas dalam melakukan penelitian energi terbarukan adalah pecarian gas dangkal yang biasa terdapat di delta-delta sungai. Lokasi yang terpilih adalah di delta Topang  Kabupaten Kepulauan Meranti, Provinsi Riau pada tahun 2015. Penelitian yang dilakukan salah satunya menggunakan metoda sub bottom profilling (SBP). Indikasi gas biogenik tampak dalam rekaman subbottom profilling berupa reflektor bebas pantul, terobosan gas dan selimut akustik. Keterdapatan gas biogenik dangkal di lokasi penelitian terjebak dalam sekuen sedimen A dan B. Sekuen A dicirikan dengan kenampakan berupa terobosan gas dan selimut akustik, sedangkan biogenik gas tipe-B dicirikan dengan kehadiran reflektor bebas pantul dengan ketebalan 10-15 meter. Sedimen yang tidak memiliki porositas seperti lempung tua merupakan lingkungan yang dimungkinkan untuk bakteri anaerobik sebagai katalisator dalam pembentukan gas biogenik. Endapan lempung tua berpotensi sebagai batuan sumber biogenik gas kemudian bermigrasi ke lapisan sedimen pasir sebagai tempat tersimpannya gas biogenik. Sebagian gas biogenik tidak dapat muncul ke permukaan hingga lapisan atas karena terjebak dalam lapisan sedimen penutup berupa lempung muda.Kata Kunci : Delta Topang, Gas Biogenik, bebas pantul, terobosan gas, selimut akustik

scholarly journals CHIRP-ENGINEERING SEISMIC METHOD FOR EXPLORING SEABED AND UNDERWATER STRUCTURES: OFF-SHORE WESTERN ANATOLIA

2020 ◽  
Vol 4 (3) ◽  
pp. 217-222
Author(s):  
Savas GÜRÇAY ◽  
Günay ÇİFTÇİ
Keyword(s):  
Active Faults ◽  
Western Anatolia ◽  
Engineering Structures ◽  
Seabed Sediment ◽  
Environmental Impact Assessments ◽  
Sediment Classification ◽  
Marine Engineering ◽  
Underwater Structures ◽  
Geotechnical Studies ◽  
Buried Faults

CHIRP systems are widely used in seabed sediment classification, submarine faults, positioning of marine engineering structures, pipeline geotechnical studies, platform and well area assessments, archaeological and environmental impact assessments. The resolution of the system is in the order of decimeter. In this study, the characteristics of submarine active faults, buried faults, seabed and underlying layers in the region were analyzed and interpreted by CHIRP data collected off-shore Seferihisar, Teke Peninsula and Alaçatı.

scholarly journals On the use of CPTs in stratigraphy: recent observations and some illustrative cases

2020 ◽  
Vol 23 (3-4) ◽  
Author(s):  
MARCO SCHILTZ
Keyword(s):  
Gamma Ray ◽  
Research Area ◽  
Limited Area ◽  
Response Patterns ◽  
Soil Behavior ◽  
Cone Penetration ◽  
Close Analogy ◽  
Cone Penetration Tests ◽  
Lithostratigraphic Units ◽  
Geological Units

During processing and interpretation of about 200 Cone Penetration Tests (CPT) with electrical cones in a limited area of 60 km² in NE Belgium, a close analogy was observed between the vertical trend and signature of two CPT derived parameters (normalized soil behavior index Ic and hydraulic conductivity kSBTn) and borehole gamma ray (GR) measurements. This close analogy could be repeatably observed on five locations with a CPT executed along a cored and logged borehole. Using this feature proves to be a considerably help for stratigraphic interpretation, especially for sandy units displaying low lithological contrast. Lithostratigraphic units and their boundaries are determined by the specific log response patterns of these CPT derived parameters (kSBTn and/or Ic). These log responses prove to be more consistent and better to correlate than for the classical parameters (cone resistance qc and friction ratio Rf). This paper describes the case of a Neogene setting in the NE of Belgium where this feature was first observed. An informal stratigraphy based on CPT log signal is proposed for the geological units for the research area. Some other cases are briefly described to illustrate the usability of this feature for other geological settings or issues.

scholarly journals Early Neolithic stone industry of the Upper Don

2018 ◽  
Vol 7 (3) ◽  
pp. 189-199
Author(s):  
Roman Viktorovich Smolyaninov ◽  
Elizaveta Sergeevna Yurkina
Keyword(s):  
Material Culture ◽  
Flood Plain ◽  
Research Area ◽  
Early Neolithic ◽  
Upper Volga ◽  
Stone Industry ◽  
Almost All ◽  
Neolithic Cultures

Features of the flood plain settlements of the river Don watershed and its tributaries is the fact that almost all of them are multi-layered. Until recently it was not possible to talk about the Early Neolithic stone industry of the Upper Don. All conclusions about Early Neolithic material culture in this territory were done by A.T. Sinyuk, based on the Middle-Don site. He described tool industry as blade technique. The paper mentions the most important sites and gives a review of Early Neolithic stone industry of the Upper Don. Nowadays there are materials of the 4 Early Neolithic cultures on the Upper Don territory: Middle-Don (72 sites), Karamyshevo (26 sites), Upper-Volga (4 sites) and Elshanskaya (4 sites) cultures. The earliest materials in the research area date VI mill. cal BC. The data on the stone industries of the Elshanskaya and Upper-Volga cultures in the Upper Don are absent. There are stone collections, which could be connected only with the Middle-Don and Karamyshevo Early Neolithic cultures. This industry could be described as flake technique.

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