To investigate characteristics of a seismogenic out‐of‐sequence thrust (OOST) imaged as a strong reflection on seismic profiles in the Nankai accretionary prism, we determined acoustic properties of discrete samples from an fossil Nobeoka OOST outcrop under confining pressures, and compared the acoustic properties with those of an active OOST in the Nankai accretionary prism. We observed anisotropy of velocity and attenuation in the hanging wall of Nobeoka OOST attributed to foliation of pelitic‐phyllite. In contrast, the footwall is composed of brittlely deformed, chaotic shales and fine sandstones, and velocities in the footwall are lower than those in the hanging wall. Amplitude variation with offset (AVO) modeling utilizing contrasts in P‐ and S‐wave velocities and densities between the hanging wall and footwall of the Nobeoka OOST indicates that fractures filled with overpressured fluid likely account for angle‐dependent reflection amplitudes of the active OOST in the Nankai Trough.

An autopsy case of multiple myeloma, IgA x type, accompanying systemic crystal‐storing histiocytosis and generalized amyloidosis, is reported. Besides multiple destructive lesions in the skeletal bones, nodular myeloma cell infiltrates were scattered in the liver, spleen, and both kidneys. Not only in these lesions but also in the reticuloendothelial organs, crystal‐storing macro‐phages appeared dispersively or in clusters. Electron microscopically, numerous crystalline inclusions contained in the cytoplasm of macrophages were membrane‐bound and of variable configuration, comprising of a homogeneous electron‐lucid material. Enzyme cytochemically, almost all of the inclusions showed acid phosphatase activity. On the basis of the results obtained from the immunohistochemical, immunofluorescent and immunoelectron microscopic studies, it was considered that the crystalline inclusions stored in the macrophages were derived from IgA x immunoglobulin secreted from the myeloma cells and were formed within secondary lysosomes by crystallization during lysosomal digestion and degradation of the ingested immunoglobulin by macrophages. Generalized amyloidosis developed in different sites from those of the crystal‐storing histiocytosis and were proven immunohisto‐chemically to belong to AL amyloidosis probably derived from a certain group of A x precursor protein.

Carbon dioxide enhanced oil recovery (CO 2 -EOR) is gaining attention as a technique for reducing environmental impact and enhancing crude oil recovery. The injected CO 2 reaches supercritical states at certain temperature and pressure conditions to be miscible with crude oil. Then, miscible CO 2 -oil mixture has lower viscosity and higher mobility than oil alone, leading to increased oil recovery rate. However, carbonate minerals are known to dissolve when CO 2 is injected into reservoirs; therefore, it is important to evaluate how properties of rocks in a carbonate rock reservoir are affected by CO 2 -EOR. In this study, CO 2 -rich water was injected on carbonate rock samples mainly collected from Middle Eastern oil field and laboratory measurements including SEM image, liquid chromatography analysis, NMR T2 relaxation time and elastic wave velocity measurement, were conducted. The dissolution states of carbonate minerals were investigated by SEM images. Furthermore, liquid chromatography analysis was applied to CO 2 -rich water flooded through the samples to detect the amount of dissolved carbonate minerals. The porosity increase estimated from the chromatography analysis could be 0.6% or higher at 100 pore volumes (PV) injection. On the other hands, it was observed that samples became shorter as injection increased. The sample shortening may be caused by mechanical compaction associated with pressure loading test. The corresponding porosity reduction due to the sample shortening was estimated; magnitude of the average value of four sample is comparable to porosity increase due to chemical dissolution. Elastic wave velocity measurements showed P-wave velocity decreased in all the samples, as the amount of CO 2 -rich water increased; P-wave velocity increase at 100 PV was 2 -10 %. S-wave velocity decrease was also observed to be 2 -4% in the most of samples. Moreover, intensity reduction of small size pore was observed by NMR T2 relaxation time analysis. Thus, it was confirmed that effects of CO 2 -rich water injection on reservoir rock properties cannot be negligible.

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