Geophysical investigations for the characterization of fractured rock aquifers in Itu, SE Brazil

Porsani, Jorge Luís; Elis, Vagner Roberto; Hiodo, Francisco Yukio

doi:10.1016/j.jappgeo.2004.10.005

Cited by 50 publications

(23 citation statements)

References 7 publications

(7 reference statements)

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“…Pembuatan jalur dilakukan dengan pemetaan kompas dan tali, serta bantuan alat navigasi Global Positioning System (GPS). Spasi elektrode ditentukan sejauh 10 m dengan panjang lintasan pengukuran di masing-masing jalur berkisar antara 300-500 m untuk mendapatkan penetrasi kedalaman maksimum sebesar 100-150 m dengan rata-rata kedalaman 30-50 m [13].…”

Section: Metodologiunclassified

Pola Tahanan Jenis dan Konduktivitas Batuan Mengandung Mineral Radioaktif di Botteng dan Takandeang, Mamuju, Sulawesi Barat

Muhammad

Indrastomo²,

Sukadana³

2017

EKSPLORIUM

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AbstrakKegiatan penyelidikan umum mineral radioaktif di daerah Mamuju, Sulawesi Barat merupakan tindak lanjut dari hasil pengukuran radioaktivitas lingkungan yang menunjukkan adanya nilai radioaktivitas tinggi. Kandungan mineral radioaktif yang cukup tinggi ditemukan antara lain di Desa Botteng dan Desa Takandeang yang tersusun oleh batuan berkomposisi leusit-basal tetapi karakteristik bawah permukaan daerah ini belum diketahui. Untuk mengetahui karakteristik geologi bawah permukaan, terkait dengan mineralisasi Uranium dan Thorium di daerah Botteng dan Takandeang, pengukuran geofisika menggunakan metode tahanan jenis dan polarisasi terimbas (Induced Polarization/IP) dilakukan. Pengukuran tersebut dilakukan menggunakan konfigurasi Wenner dan dipole-dipole, dimulai dengan pembuatan enam jalur pengukuran, masing-masing tiga jalur: GF/BTGY-01, GF/BTGK-02, dan GF/BTGK-04 di Botteng, dan tiga jalur lainnya: GF/TKDK-01, GF/TKDK-07, dan GF/TKDY-06 di Takandeang. Pengukuran dilakukan dengan memotong arah kemenerusan anomali radiometri permukaan. Hasil pengukuran menunjukkan keterdapatan anomali berada pada sebaran batuan autobreksia yang terlihat jelas di lokasi GF/TKDY-6, GF/TKDK-07, dan GF/BTGK-04. Beberapa indikasi mineralisasi di permukaan teridentifikasi di penampang GF/BTGK-02 dan GF/TKDK-01, dicirikan dengan anomali-anomali chargeabilitas >25,14 ms di lintasan GF/BTGK-02 dan 81,4 ms di GF/TKDK-01. Anomali yang signifikan direkomendasikan sebagai lokasi pemboran. AbstractThe general investigation activities of radioactive minerals in Mamuju Area, West Sulawesi is a respon of the environmental radioactivity measurement result, which shows the existence of high radioactivity value. High radioactive mineral content found in Botteng and Takandeang Villages. From the outcrops, they composed of leucite-basalt rocks; meanwhile the subsurface characteristics of this area are unknown. To characterize the subsurface geology, related to uranium and thorium mineralization in Botteng and Takandeang area, geophysical measurement conducted using resistivity and Induced Polarization (IP) methods. The measurements carried out using Wenner and dipole-dipole configurations. The measurements started with the creation of six measurement paths where three lines: GF/BTGY-01, GF/BTGK-02, and GF/BTGK-04 are in Botteng and three other lines: GF/TKDK-01, GF/TKDK-07 and, GF/TKDY-06 are in Takandeang. Measurements conducted by crossing the surface radiometric anomaly distribution. The result showed anomaly occurences on autobreccia distribution in GF/TKDY-6, GF/TKDK-07, and GF/BTGK-04 locations. Several mineralization indication on surface identified in GF/BTGK-0, and GF/TKDK-01 sections, charaterized by chargeability anomalies more than 25.14 ms and 81.4 ms respectively. All significant anomalies are recomended as drilling location.

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Section: Metodologiunclassified

Pola Tahanan Jenis dan Konduktivitas Batuan Mengandung Mineral Radioaktif di Botteng dan Takandeang, Mamuju, Sulawesi Barat

Muhammad

Indrastomo²,

Sukadana³

2017

EKSPLORIUM

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“…국외에서는 유류오염물질을 탐사하기 위한 실험실 및 탱크모델 실험 (DeRyck et al, 1993;Daniels et al, 1995), 충적대수층의 정밀한 층서퇴적학적 구조 파악 (Steeples and Miller, 1990;Beres and Haeni, 1991;Fielding et al, 1999;Corbeanu et al, 2001), 지하수 면(groundwater table)과 토양수분함량의 측정 및 관측 (Hargey and Müller, 2000), 양수시험 시 자유면대수층 의 공간적 반응 및 수리특성 추정 (Endres et al, 2000;Lu and Sato, 2004), 단열암반대수층의 특성 평가 (Porsani et al 2005), 지하수면, 수리전도도와 함수량의 수리특성 추정 (Lu and Sato, 2007), LNAPL 오염평가 (Cassidy, 2007), 동역학적 지하수면으로부터 GPR 반사 면의 원인을 판정하기 위한 실내시험 (Pyke et al, 2008), 탄광지역에서 식물성장에 영향을 미칠 수 있는 토양수분과 지하수면 변화를 분석하기 위한 모니터링 방 법 (Bian, et al, 2009), 지하수 인공함양에 따른 불포화 대(vadose zone)의 시간경과에 따른 침투과정과 함수량 의 공간적 분포 (Kuroda et al, 2009), 시추공간 레이더 에 의한 불포화층의 효율적인 전자기 영상화와 ZeroOffset Profiling (ZOP)의 초동 주시 역산을 이용한 함 수율 변화 (Jang et al, 2011a;Jang et al, 2011b), 다 중 오프셋 단공과 시추공간 레이더 반사자료를 이용한 화강암 대수층에서의 단열 영상분석 (Dorn et al, 2012) 등에 관한 GPR 관련 연구가 수행되었다.…”

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Estimation of Groundwater Table using Ground Penetration Radar (GPR) in a Sand Tank Model and at an Alluvial Field Site

Kim¹,

Kim²,

Choi³

et al. 2013

The Journal of Engineering Geology

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Ground penetrating radar (GPR) surveys were conducted in a sand tank model in a laboratory and at an alluvial field site to detect the groundwater table and to investigate the influence of saturation on GPR response in the unsaturated zone. In the sand tank model, the groundwater table and saturation in the sand layer were altered by injecting water, which was then drained by a valve inserted into the bottom of the tank. GPR vertical reflection profile (VRP) data were obtained in the sand tank model for rising and lowering of the groundwater table to estimate the groundwater table and saturation. Results of the lab-scale model provide information on the sensitivity of GPR signals to changes in the water content and in the groundwater table. GPR wave velocities in the vadose zone are controlled mainly by variations in water content (increased travel time is interpreted as an increase in saturation). At the field site, VRP data were collected to a depth of 220 m to estimate the groundwater table at an alluvial site near the Nakdong river at Iryong-ri, Haman-gun, South Korea. Results of the field survey indicate that under saturated conditions, the first reflector of the GPR is indicative of the capillary fringe and not the actual groundwater table. To measure the groundwater table more accurately, we performed a GPR survey using the common mid-point (CMP) method in the vicinity of well-3, and sunk a well to check the groundwater table. The resultant CMP data revealed reflective events from the capillary fringe and groundwater table showing hyperbolic patterns. The normal moveout correction was applied to evaluate the velocity of the GPR, which improved the accuracy of saturation and groundwater table information at depth. The GPR results show that the saturation information, including the groundwater table, is useful in assessing the hydrogeologic properties of the vadose zone in the field.

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“…214 Bi (Bismuth), which is the decay product of 222 Rn, has been measured by gamma-ray spectrometer to detect locations of active faults (Porsani et al, 2005, Imaizumi et al, 2010. The dominant gamma rays from 214 Bi are both higher in intensity and energy than the gamma rays of other 222 Rn decay products.…”

Section: Gamma Ray Spectrometer Applicationmentioning

confidence: 99%

“…Thus, a window of the gamma ray spectrometer is applied to measure all the gamma rays within the 1.65-1.87 MeV, multiples electron volt (peak is at 1.76 MeV) energy range. The observed gamma rays in this range are not only from 214 Bi but also from 208 T1 (Compton noise) which is in the 232 Th (thorium) decay series (Porsani et al, 2005). Therefore, a stripping ratio is employed to achieve an accurate 214 Bi measurement (LaBrecque et al, 2004).…”

Section: Gamma Ray Spectrometer Applicationmentioning

confidence: 99%

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Preferential flow paths in a complex coal seam system

Ma¹

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Prior to commencing coal mining operations, measurements of permeable geological structures are an important task in the mine site exploration to facilitate the understanding of potential mining impacts on the adjacent river and groundwater systems. These potential environmental impacts are likely to be controlled predominately by preferential flow zones provided by faults and fractures, which are known to enhance the transport of gas and water. However, detailed mapping of these geological structures is rarely carried out in mining areas. In order to develop a feasible and rapid survey method, two field campaigns, involving soil gas mapping and gamma ray survey, were designed and carried out a at coal mine site in the Hunter River Valley, NSW, Australia. All measured parameters (radon, gamma ray and CO 2 ) revealed similar anomaly distribution patterns though measured by different techniques over different time periods (1.5 years elapsed between two field campaigns). Geophysical modelling (based on borehole logging results) and soil gas mapping were conducted independently, and both results indicated the existence of geological structures crossing the sampling region. Results of this study confirm the applicability of high intensity soil gas mapping methods for locating active tectonics faults covered by alluvium in the decametre scale. Additionally, compared with labour-intensive soil gas mapping methods, the gamma ray survey is capable of providing relatively reliable results in a fast and convenient way to cover a relatively large field site.The basic principles and controlling parameters for gas seepage from deep formations to the surface are not fully understood. In order to better understand gas transport mechanisms in the subsurface environment so that the soil gas mapping data can be better interpreted, laboratory experiments were conducted to investigate the flow of discrete microbubbles through a saturated porous medium as part of a rapid gas transport pathway from deep ground formations to the ground surface. During the experiments, bubbles, released from a point source, moved upward through a quasi-2D flume filled with transparent water-based gelbeads and formed a distinct plume that could be well captured by a calibrated camera. Outflowing bubbles were collected on the top of the flume using volumetric burettes for flux measurements. We quantified the scaling behaviour between the gas (bubble) release rates and various characteristic parameters of the bubble plume, including plume tip velocity, plume width and breakthrough time of plume front. The ii experiments also revealed circulations of ambient pore water induced by the bubble flow.Based on a simple momentum exchange model, we showed that the relationship between the mean pore-water velocity and gas release rate is consistent with the scaling solution for the bubble plume. These findings have important implications for studies of soil gas mapping and gas emission (including hydrocarbon gases) from deep ground formations as well as fund...

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Geophysical investigations for the characterization of fractured rock aquifers in Itu, SE Brazil

Cited by 50 publications

References 7 publications

Pola Tahanan Jenis dan Konduktivitas Batuan Mengandung Mineral Radioaktif di Botteng dan Takandeang, Mamuju, Sulawesi Barat

Pola Tahanan Jenis dan Konduktivitas Batuan Mengandung Mineral Radioaktif di Botteng dan Takandeang, Mamuju, Sulawesi Barat

Estimation of Groundwater Table using Ground Penetration Radar (GPR) in a Sand Tank Model and at an Alluvial Field Site

Preferential flow paths in a complex coal seam system

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