Abstract.Intraplate earthquake zones in the back arc of NE Japan were imaged by wide-band magnetotelluric

We obtained an electrical transect image of the Niigata‐Kobe Tectonic Zone (NKTZ). Several major active faults are located in this zone of concentrated deformation. The main features of the final two‐dimensional model are a thick resistive block in the upper crust, with a thinned‐out portion beneath the Atotsugawa Fault, and a strong conductor in the lower crust that intrudes upward into the upper resistor. The upper crustal resistive zone corresponds well to the spatiality of the NKTZ, and relatively conductive zones sandwiching this resistor may contribute to observed changes in displacement rates. The overlapping locations of the conductor and the low‐velocity body in the lower crust indicate that the conductor represents a zone that was weakened by fluids. Given that microearthquakes are localized in the regions between the resistive and conductive zones, we suggest that the distribution of earthquakes is influenced by intrusions of fluid derived from the conductor.

In modern industrial society, molybdenum is one of the important metals for development of the industry of rare metals. It is important to recycle the rare metals from wastes because they are technically and economically difficult to be dug and be purified, and they exist in only a few regions in the world. In this study, ModE protein derived from Escherichia coli, which is a molybdate-dependent transcriptional regulator with the ability to bind molybdate as a form of soluble molybdenum, was displayed on the yeast cell surface by alpha-agglutinin-based cell surface display system for the adsorption and recovery of molybdate. Displayed ModE, confirmed by immunofluorescence labeling, caught molybdate more preferably at pH 3.0 than at basic pH. Yeast cells displaying C-terminal domain of ModE, which lacks N-terminal DNA binding domain, more effectively adsorbed molybdate than those displaying full-length ModE, suggesting that the deletion of the domain unrelated to metal binding enhanced the binding ability. Our results indicated that the adsorption system on cell surface of yeast cells displaying ModE is effective not only for adsorption of molybdate as a rare metal bioadsorbent but also for the easy recovery of molybdate located on the cell surface.

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The 2008 Iwate-Miyagi Nairiku earthquake (M 7.2) was a shallow inland earthquake that occurred in the volcanic front of the northeastern Japan arc. To understand why the earthquake occurred beneath an active volcanic area, in which ductile crust generally impedes fault rupture, we conducted magnetotelluric surveys at 14 stations around the epicentral area 2 months after the earthquake. Based on 56 sets of magnetotelluric impedances measured by the present and previous surveys, we estimated the three-dimensional (3-D) electrical resistivity distribution. The inverted 3-D resistivity model showed a shallow conductive zone beneath the Kitakami Lowland and a few conductive patches beneath active volcanic areas. The shallow conductive zone is interpreted as Tertiary sedimentary rocks. The deeper conductive patches probably relate to volcanic activities and possibly indicate high-temperature anomalies. Aftershocks were distributed mainly in the resistive zone, interpreted as a brittle zone, and not in these conductive areas, interpreted as ductile zones. The size of the brittle zone seems large enough for a fault rupture area capable of generating an M 7-class earthquake, despite the areas distributed among the ductile zones. This interpretation implies that 3-D elastic heterogeneity, due to regional geology and volcanic activities, controls the size of the fault rupture zone. Additionally, the elastic heterogeneities could result in local stress concentration around the earthquake area and cause faulting.