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Volume 43 (2002 - 200･･･
- Issue 6 Pages 345-
- Issue 5 Pages 270-
- Issue 4 Pages 208-
- Issue 3 Pages 124-
- Issue 2 Pages 66-
- Issue 1 Pages 2-
Volume 43, Issue 4
Displaying 1-7 of 7 articles from this issue
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Toshifumi IGARASHI, Takafumi IZUTSU, Yasumichi OKA2002 Volume 43 Issue 4 Pages 208-215
Published: October 10, 2002
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSBatch leaching experiments in aerated conditions for two different types of crushed pyrite were carried out by measuring changes in pH and concentrations of Fe and SO4 for leachate. The results showed that leachate pH depended on the solid-liquid ratio and leaching period as well as the pyrite used, and that the electric conductivities and the concentrations of Fe and SO4 increased with the decrease in leachate pH. The chemicalforms of iron and sulfur in the leachate were identified as ferrous ions and sulfate ions, respectively. The concentrationchanges observed illustrated that the initial leaching rates of ferrous and sulfate ions from both pyrite samples were demonstrated by a first-order reaction with respect to the solid-phase concentration. This indicates that the initial dissolution process was governed by a surface reaction. On the other hand, the subsequent dissolution of one of the samples was expressed by a function of the square root of the leaching period, suggesting that the rate-determining process was diffusion in the crushed pyrite sample. These two different mechanisms were found to affect the dissolution rate of pyrite. Therefore, the initial leaching may be expected to be more critical to the chemical properties of leachate than the following leaching, due to the estimated diffusion coefficient within the pyrite being as low as 10-16 cm2/s. In addition, the diameter of the crushed pyrite affected the chemical properties of the leachate, but not the leaching rate.View full abstractDownload PDF (1931K) -
Ken-ichi NISHIYAMA, Yukinori MATSUKURA2002 Volume 43 Issue 4 Pages 216-225
Published: October 10, 2002
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSTemporal changes in rock properties due to weathering during 350 ka were examined using sandstone gravel in fluvial terrace deposits with a known emergence time which were distributed in the Miyazaki Plain, South Kyushu.
The physical and mechanical properties and the colour index of b*-value change during the 0-to 120-ka period. The patterns of temporal changes in these rock properties are similar. The colour index of a*-value and pore radius change during 250-to 350-ka period. These results show that connected pores and content of hematite increase during 250-to 350-ka period. The specific surface area and the chemical weathering indices change at constant rates during 350 ka. This pattern suggests that chemical reactions occurred actively at the surface of the minerals with a large specific surface area. Since the specific surface area of sandstone increases at a constant rate during 350 ka, the chemical weathering indices change at a constant rate during 350 ka.View full abstractDownload PDF (1783K) -
A Case Study of the West Yauneyama Fault in Southwestern Shimane Pref.Kouzaburo FUKUZUKA, Yuji KANAORI2002 Volume 43 Issue 4 Pages 226-234
Published: October 10, 2002
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSIn this study, geomorphologic and geologic features of the West Yauneyama fault in southwestern Shimane Prefecture, are clarified from geomorphological analysis, geological mapping, andi nvestigations of fault outcrops. Regional relationship between the fault and a seismic activity zone is also examined by the catalog of the Japan Meteorological Agency. Crustal structure of the West Yauneyama fault is discussed by using a compiled gravity anomaly map. Geologic and topographic investigations indicate that the ENE-to NE-trending West Yauneyama fault is approximately 30 km long, extending from Kanagi Town to Hikimi Town, Shimane Prefecture. Based on the certainty of lineaments and the occurrence of tectonic landforms, the West Yauneyama fault is tentatively divided into northern and southern segments. The geomorphologic feature suggests that the northern segment has probably moved right-laterally during the Quaternary. Systematically right-lateral deflection or bend can be detected in a number of channels across this segment. In contrast, the southern segment has no movement during the Quaternary because of a lack of tectonic landforms. A seismic activity of magnitudes of greater than 2 occurs along the northern segment of the West Yauneyama fault, and a steep gradient of gravity anomalies ranging from 2 to 3 mgal/km can also be detected along it, while around the southern segment, no seismic activity has been observed in the period from October 1 in 1997 to July 31 in 2001, and a shallow gradient of gravity anomalies ranging from 0.5 to 1.5 mgal/km can be found. This suggests that the northern segment of the West Yauneyma fault extends down a deep depth in the Earth's crust.View full abstractDownload PDF (4216K) -
Manabu TAKAHASHI, Weiren LIN, Tetsuro HIRONO, Yuzuru YAMAMOTO2002 Volume 43 Issue 4 Pages 235-238
Published: October 10, 2002
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSTo visualize the microstructure in rocks, micro focus X ray CT images that can get three-dimensional data simultaneously with high resolution of 10 micron have been introduced. We obtained multi planar reconstruction images in intact Berea sandstone and Shirahama sandstone. In the intact rocks, pore structures and grain boundaries are distinguished well. Furthermore, existence of the crushed grains arrangements and fracture band is confirmed definitely in the compressed Berea sandstone under confining pressure of 12 MPa. Micro focus X ray CT is rather effective in visualizing the microstructures in rocks.View full abstractDownload PDF (2071K) -
Sigenobu HIRAIDE, M. B. COLLADO, J. D. RONDAL, Kouichi SUZUKI, Wataru ...2002 Volume 43 Issue 4 Pages 239-243
Published: October 10, 2002
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESS1991 Mt. Pinatubo eruption has caused changes of groundwater in Mt. Pinatubo area. A simple and valid method is demanded to estimate groundwater level for the development of shallow well irrigation system. HIRAIDE et al. (2001) reported that electrical exploration could be applied to investigate groundwater in Pasig-Potrero river area. This study aims to discuss the evaluation of electrical prospecting 1D method (ρ-a method) for a feasible groundwater exploration method. Boring and measurement of groundwater level were performed to verify the precision of groundwater estimation by electrical prospecting 1D method.
The results obtained in this study are summarized as follows.
1) Boring investigation proved that one dimension sounding (ρ-a method) was able to estimate geological stratum and groundwater level.
2) Repeating measurement conducted in the same site revealed that exploration results from one dimension sounding were reproducible regardless of rainfall.
3) From the comparison of analytical data for both wet and dry season, it is clarified that electrical prospecting 1D method. is precise enough to use in full season as a practical method for estimating groundwater level. The accuracy of estimated groundwater level was obtained as 1.1-1.2mView full abstractDownload PDF (967K) -
Satoru KAWASAKI, Chikaosa TANIMOTO, Kazuhiro KOIZUMI, Masaki ISHIKAWA2002 Volume 43 Issue 4 Pages 244-248
Published: October 10, 2002
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSThe Equotip hardness tests, unconfined compression tests and elastic wave tests were conducted using rock cores sampled from several sites in Japan, and a consideration of correlations between obtained hardness indexes and mechanical properties was carried out. As a result, it was found that there was a fair possibility of estimating the values of unconfined compressive strength using hardness indexes.View full abstractDownload PDF (772K) -
[in Japanese]2002 Volume 43 Issue 4 Pages 249-256
Published: October 10, 2002
Released on J-STAGE: February 23, 2010
JOURNAL FREE ACCESSDownload PDF (5967K)
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