Statistical thermodynamic modeling to estimate the phase equilibrium conditions of gas hydrate
		Experiment on cross-well seismic reflection survey using shallow holes
		Litho- and tephrostratigraphy of the Yuhigaoka boring cores from the Osaka Plain, central Japan
		Micro-PIXE analyses of trace elements in a stainless steel and silicate glasses
		Abstracts for Geological Survey Seminar, no. 254

Statistical thermodynamic modeling to estimate the phase equilibrium conditions of gas hydrate

Tatsuo Maekawa and Noboru Imai

1997

vol. 48 (12), p. 645-651, 6 figs. 1 table.

Keywords: gas hydrate, clathrate hydrate, statistical thermodynamic modeling, phase equilibrium condition

Abstract: The understanding of the phase equilibrium conditions of natural gas hydrates is essential for the estimation of potential resources of gas hydrate, which can be predicted not only from laboratory experiments but also by statistical thermodynamic models. We have developed the statistical thermodynamic model of gas hydrate based on the theory presented by van del Waals and Platteeuw (1959). We have estimated the two important parameters, △μ^L _w,o and △h_w,o, using the equilibrium conditions for methane hydrate as determined by laboratory experiments. We obtained optimal values of 1247J/mol and -4951J/mol for these parameters, respectively.

Experiment on cross-well seismic reflection survey using shallow holes

Jun Matsushima, Toshiyuki Yokota, Naomi Kano, Kazuo Yamaguchi and Tsutomu Kiguchi

1997

vol. 48 (12), p. 653-660, 13 figs., 2 tables.

Keywords: cross-well survey, seisemic reflection, diffraction stacking, high resolution

Abstract: Cross-well seismic records were collected in the test field within the premise of Tsukuba Research Center, AIST． In general, characteristics of cross-well records are as follows; (1) cross-well records have higher resolution than surface seismic survey records because the source and receiver layout of cross-well survey is closer to targets, (2) the survey is free from a low velocity layer near surface that attenuates high frequency waves, and (3) the survey is free from surface waves． Two types of receiver (3-component geophones and borehole shuttles) were used for data acquisition． The records acquired with 3-component geophones show a high signal to noise ratio because of its hard coupling with ground． Diffraction stacking with velocity analysis was applied to cross-well seismic records acquired with 3-component geophones． The result indicates that cross-well reflector imaging can produce higher resolution subsurface imaging than surface seismic reflection methods． In addition, one dimensional numerical experiments illustrated that it is necessary to take care when interpretating the stacked record by use of high frequency observed data.

Litho- and tephrostratigraphy of the Yuhigaoka boring cores from the Osaka Plain, central Japan

Syusaku Yoshikawa, Eikichi Tsukuda, Muneki Mitamura, Kouichi Nakagawa, Kiyohide Mizuno, Aiko Higashiwaki, Kyouko Kataoka and Makoto Takahashi

1997

vol. 48 (12), p. 661-672, 3 figs., 1 tables.

Keywords: Osaka Plain, Quaternary, Osaka Group, lithostratigraphy, tephrostratigraphy, volcanic ash layer, boring-core

Abstract: In 1996, 600-meter deep core boring was carried out at Yuhigaoka (Latitude 34゜39' 17", Longitude 135゜30' 54"), Osaka City in the central part of the Osaka Plain. The core samples mainly consist of unindurated sand, gravel, silt and clay, ranging in age from the late Pliocene to middle Pleistocene. The core sediments are lithologically divided into YU-A and YU-B formations, in ascending order. The YU-A Formation is composed of fluvio-lacustrine gravel, sand and silt, with YU542, YU400 and YU384 volcanic ash layers. The YU542 volcanic ash layer correlates with the Fukuda volcanic ash layer, which exists at the horizon of the boundary between the lowermost and lower parts of the Osaka Group. The YU-B Formation is composed of alternating beds of marine clay and fluvio-lacustrine sand and silt, and intercalates eighteen volcanic ash layers. In these volcanic ash layers, YU261, YU210, YU173, YU163, YU128 and YU65 layers correlate with the Yellow, Pink, Komyoike・, Yamada・, Azuki, Hacchoike・ volcanic ash layers of the Osaka Group, respectively. On the basis of these correlations, nine marine clay-beds in the YU-B. Formation have been identified as the Ma-1, Ma0, Ma1, -----, Ma6 and Ma7, in ascending order.

Micro-PIXE analyses of trace elements in a stainless steel and silicate glasses

Masanori Kurosawa, Hideyuki Ohyi, Yasushi Deguchi, Satoshi Murao, William J. Teesdale and John L. Campbell

1997

vol. 48 (12), p. 673-689, 10 figs., 2 tables.

Keywords: PIXE, ion beam, quantitative analysis, stainless steel, silicate glass

Abstract: Twenty three trace elements in a stainless steel (GK-19) and four silicate glasses (JA-1, JB-1a, JF-1, JGb-1) were analyzed by the micro-PIXE at the University of Guelph, to evaluate the accuracy of determination in transition metal analysis. For the stainless steel, obtained Ni concentration agreed well with the recommended value (10.36 wt.%) with 3% error, showing an excellent correction for secondary fluorescence effect in the analytical software. Measured concentrations of Mn, Co and Cu agreed with recommended values within ±10% (average). For the silicate glasses, Mn and Cu contents determined in this study were 20% and 40% lower than the recommended values. The discrepancies may be due to systematic errors of fitting procedure in the analytical software and loss of Cu during the glass preparation. Ni contents of JB-1a and JGb-1 agreed with the recommended values with 15% and 3% errors. The other trace element concentrations agreed with the recommended values within ±9% (JA-1, JB-1a), ±10% (JF-1) and ±16% (JGb-1).

Abstracts for Geological Survey Seminar, no. 254 -Geology supporting human activities in and around the Tokyo Megalopolis-

1997

vol. 48 (12), p. 691-696.