Bentonite is widely used for various industrial fields. Many borings are carried out for investigation of subsurface bentonite bodies now. It is required to develop an effective method for bentonite exploration instead of the boring, which requires high cost and gives only local geology information. The resistivity of bentonite is generally very low because it contains a lot of smectite which has high conductivity. It means that the geoelectrical method is suitable for bentonite exploration. In order to confirm it, we conducted a DC resistivity survey experiment at the Dobuyama bentonite deposit, Miyagi prefecture, Northeast Japan. The analyzed 2-D resistivity sections indicate that low-resistivity zones correspond to the bentonite bodies confirmed by surface geology and many exploration borings in this area. We also considered the relation between resistivity and methylene blue adsorption that is used as an index of the quality of a bentonite. A good correlation was found between the resistivity and the methylene blue adsorption of bentonite-bearing samples. Using the correlation, we estimated the sections of methylene blue adsorption from the resistivity sections. The zones which show the high value of methylene blue adsorption correspond to the bentonite bodies found by the borings. This fact indicates that the geoelectrical method is effective for bentonite exploration and evaluation.

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 Depth structure maps were estimated from both their time structure maps and well top data using a geostatistical approach, and seismic attribute time volumes were converted to their depth volumes in the oil-sands reservoir in Alberta, Canada. The objective of the study was to provide basic information in the depth domain for constructing three-dimensional (3D) geological depth models of the oil-sands reservoir.
 Well log information is precise vertically, but sparse sampled data horizontally. Seismic interpretation time data are less precise than well log data vertically, but dense, well-sampled data horizontally. The seismic interpreted horizons and the well depth information of the reservoir top and bottom were geostatistically integrated to estimate the depth structure maps of them. Time volumes were also converted to their depth volumes using simple relationships between the time structure maps and the depth structure maps of the reservoir top and bottom on the assumption that the seismic interval velocities in the reservoir interval vary horizontally, but they were vertically constant.
 After the study, five new wells were planned and drilled in the study area. Depth prediction errors of the reservoir top and bottom were less than two meters at the wells. The geostatistical approach continued to be applied to the other four 3D seismic surveys acquired later in the adjacent oil-sands areas, and depth structure maps and depth seismic attribute volumes estimated by the method were helpful for geological interpretation studies in those area.

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 Tomographic analysis was conducted using surface wave group velocity estimated with a seismic interferometric process of continuous microtremor data obtained at stations in the southern Kanto area by Yamanaka et al. (2010). The region is divided into 0.125° cells with a constant group velocity in the tomographic analysis. The tomographic image is constructed using the Simultaneous Iterative Reconstruction Technique for slowness of Rayleigh and Love waves. The tomographic maps of the surface wave group velocities at periods of 2 to 6 seconds show the regional variations of the group velocity dispersion curve. We found that the regions of Tokyo bay and lowland have low group velocities, while the western marginal parts of the Kanto basin and the Izu peninsula have high group velocities. The comparison of the tomographic maps between the observed and calculated ones by the existing 3D basin model shows significant differences in the regions of the Izu peninsula, basin edge and Sagami bay. The resulting dispersion curve of the surface wave group velocity in each cell was inverted to a 1D S-wave velocity profile in order to validate the existing 3D model. The results show that the thicknesses of the sedimentary layers are thinner than the previous model in the region of Sagami bay where the differences of the group velocity were significant. It also indicates the possibility of an existence of the sediment layers of the Izu peninsula about 1km deep.

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 The offshore of Niigata, where earthquake source faults that caused the 1964 Niigata earthquake and the 2007 Chuetsu-Oki earthquake are distributed, is located in the high strain rate belt. However, most of offshore geology is poorly known due to limit of observation. To understand geological structure of the southwest Niigata coastal area, we conducted two high-resolution seismic reflection surveys including a offshore-onshore integrated seismic reflection profile, which runs across a northern extension of inland active reverse fault along the eastern foot of the Kakudayama, and we also reprocessed two seismic reflection survey lines which conducted by JNOC (Japan National Oil Corporation; presently Japan Oil, Gas and Metals National Corporation). These data were processed by conventional common mid-point (CMP) stack methods. Reflectors imaged in these seismic profiles correlate with strata defined in boreholes drilled in offshore of the Niigata. These profiles indicate that the Kakuda-Yahiko Fault, inland active fault along eastern foot of the Kakuda-Yahiko massif, continues to sea obviously, and that the Kakuda-Yahiko Fault deformed Pliocene sedimentary strata as east vergent broad monocline. On the basis of the structural relief within Miocene to Pliocene strata, it is presumed that the Kakuda-Yahiko Fault is a reactivated Miocene normal fault since Nishiyama Formation deposition period. Moreover, the deformations of the top of the Nishiyama Formation show that the monocline, related with the Kakuda-Yahiko Fault, extends to approximately 2 km wide, and also that the trace of the Kakuda-Yahiko Fault has geometric irregularity such as bends and branches near present shoreline.

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 Bentonite is widely used for various industrial fields. The resistivity of bentonite is generally very low because it contains a lot of smectite which has high conductivity. It means that the electrical and electromagnetic methods are suitable for bentonite exploration. In order to confirm it, we measured the resistivity with other physical and chemical properties of the samples of bentonites and surrounding rocks of the Kawasaki and Tsukinuno bentonite mines. The resistivity is well correlated with the water content and the free swell. Except the rocks containing zeolite, the resistivity is also related to the cation exchange capacity (CEC). A good correlation was found between the resistivity and the methylene blue adsorption that is used as an index of the quality of a bentonite. These facts indicate that electrical and electromagnetic surveys are effective for subsurface bentonite exploration and evaluation.

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