Physical property anisotropy of foliated fault rocks: Study from the Nobeoka Thrust,Shimanto Belt,southwest Japan

To investigate the physical property anisotropies of foliated fault rocks in subduction zones, the hanging wall phyllites and footwall cataclasites exhumed along the Nobeoka Thrust, a fossilized out‐of‐sequence‐thrust in the Shimanto Belt, Japan, was focused. Discrete physical property (electric resistivity, P‐ and S‐wave velocities, and porosity) measurements were conducted employing geologic coordinates (depth‐parallel direction, strike direction, and maximum dip direction of foliation), using the core samples obtained from the Nobeoka Thrust Drilling Project and compared the data to borehole geophysical logs. A higher sample P‐wave velocity (Vp), lower S‐wave velocity (Vs), higher Vp/Vs, and lower sample porosity and resistivity compared to the logs, are inferred to have been caused by the larger sampling scale of the logs and lower fluid saturation of the borehole. The phyllites and cataclasites exhibited substantial vertical and horizontal anisotropy of Vp (0.4–17.3 % and 2.7–13.8 %, respectively), Vs (0.5–56 % and 7.7–43 %, respectively), and resistivity (0.9–119 % and 2.0–65.9 %, respectively). The physical property anisotropies are primarily affected by the dip angles of foliation. The fault rocks that have gentler dip angles exhibit a higher Vp in the strike and maximum dip direction and a lower Vp in the depth‐parallel direction. In contrast, the fault rocks that have steeply dipping structures show a higher Vp in the strike and depth‐parallel directions with a lower velocity in the maximum dip direction. Resistivity anisotropy show a trend opposite to that of the Vp in relation to the dip angles. Our results show lower Vp anisotropy than those obtained in previous studies, which measured wave speeds perpendicular or parallel to foliation under confining pressure. This study highlights the significance of dip angles on vertical properties in geophysical surveys across foliated fault rocks.     

Spatio-temporal streamflow generation in a small,steep headwater catchment in western Japan

Headwaters contribute a substantial part of the flow in river networks. However, spatial variations of streamflow generation processes in steep headwaters have not been well studied. In this study, we examined the spatio-temporal variation of streamflow generation processes in a steep 2.98-ha headwater catchment. The time when baseflow of the upstream section exceeded that downstream was coincident with the time when the riparian groundwater switched from downwelling to upwelling. This suggests that upwelling of the riparian groundwater increased considerably in the upstream section during the wet period, producing a shift in the relative size of baseflow between the upstream and downstream sections. The timing of fluctuations among hillslope soil moisture, hillslope groundwater and streamflow reveals that the hillslope contributed to storm flow, but this contribution was limited to the wet period. Overall, these results suggest that streamflow generation has strong spatial variations, even in small, steep headwater catchments.

EDITOR A. Castellarin ASSOCIATE EDITOR X. Chen     

Production of the Blood Pressure Lowing Peptides from Brown Alga ( Undaria pinnatifida )

1 IntroductionIncreased blood pressure appears to be one of theprimary risk factors of circulatory organ diseases suchas encepharo-apoplexy, encepharo-infarction and cardi-ac infraction. Angiotensin-I-converting enzyme (ACE)plays an important role in the rennin-angiotensin sys-tem by regulating blood pressure. Antihypertensivedrugs such as captopril and enalapril are potent ACEinhibitors (Ondetti et al., 1977). Recently, severalinhibitory peptides derived from food proteins havebeen isolat…     

Navigation message demodulation for GPS receiver on-board spinning rockets

We describe a demodulation scheme for the navigation message of GPS receivers on spin-stabilized rockets. Doppler frequencies due to fast and complex dynamics, in particular high-rate spin, cause errors in carrier frequency tracking. The effects of such errors on navigation message demodulation are described through theoretical analysis and numerical simulation. A demodulation scheme that includes a frequency estimator is proposed to account for frequency tracking errors. It is demonstrated that demodulation performance is degraded 5 dB due to frequency uncertainty. Simulation results showed that a demodulator which includes maximum likelihood (ML) frequency estimator achieves near-optimal symbol error rate under these conditions. Demodulation with ML estimator achieves a bit error rate below 10^?5 for a C/N ₀?=?35 dB–Hz, for spin rates below 2.7?Hz, and a rocket radius smaller than 1 m. For the cases in which computational capabilities of the on-board GPS receiver is insufficient to implement the demodulator with ML estimator, frequency estimation methods with low complexity were also tested through numerical simulation. The proposed Kay and Quinn-Fernandes combination achieves a bit error rate below 10^?5 for a C/N ₀?=?37 dB–Hz while requiring 1/10 of processing time.     

The Megadeltas of Asia: interlinkage of land and sea,and human development

This special issue describes research arising from the megadelta project of the Asia‐Pacific‐Networks (APN), undertaken between 2004 and 2009 ( www.megadelta.ecnu.edu.cn ). Numerous delta‐coast scientists from more than 20 countries were involved in the project concerned with developing our knowledge of land–estuarine–coastal interactions in megadeltas, and with fusing this knowledge with societal development and management. Project workshops were held in Bangkok (2004), Ho Chi Minh City (2005), Dhaka (2007) and Shanghai (2008) with over 500 participants. The main objectives of the project were: (1) development of regional databases; (2) understanding of delta formation and associated fluxes between land and sea; (3) knowledge transfer and building research capacity; and (4) understanding how better social management might follow. Copyright © 2011 John Wiley & Sons, Ltd.     

Long-term high-frequency measurements of dibromomethane in the atmosphere at algae-rich and algae-poor coastal sites

Dibromomethane (CH₂Br₂), a natural stratospheric ozone depleting substance, is mostly emitted from the ocean, but the relative importance of coastal (or macroalgae) and open ocean emissions is unknown. We made long-term high-frequency measurements of CH₂Br₂ concentrations at two remote coastal sites in Japan, on the subtropical Hateruma Island (poor in macroalgae) and at Cape Ochiishi (rich in macroalgae). CH₂Br₂ concentrations at Hateruma showed prominent seasonal variation, being lower in summer (around 0.94 ppt) than in winter (around 1.23 ppt). In contrast, CH₂Br₂ concentrations at Ochiishi were highly variable, often exceeding 2 ppt in the summer but with minimum baseline concentrations close to those from Hateruma; in the winter the concentrations were almost constant at about 1.3 ppt. Analysis of the data suggested that (1) emissions from macroalgae were not likely to extend offshore, but instead were localized near the shore, (2) strong macroalgal emissions of CH₂Br₂ were almost limited to the summer, but it was not reflected in the seasonality of the baseline concentrations of CH₂Br₂ in the atmosphere, and therefore (3) macroalgal or coastal emissions of CH₂Br₂ in the temperate zone might have a rather limited contribution to the global CH₂Br₂ sources. These findings are especially important for the understanding of the tropospheric and stratospheric bromine budget.     

Ground motion characteristics and shaking damage of the 11th March 2011 M w9.0 Great East Japan earthquake

A catastrophic M _w9.0 earthquake and subsequent giant tsunami struck the Tōhoku and Kanto regions of Japan on 11th March 2011, causing tremendous casualties, massive damage to structures and infrastructure, and huge economic loss. This event has revealed weakness and vulnerability of urban cities and modern society in Japan, which were thought to be one of the most earthquake-prepared nations in the world. Nevertheless, recorded ground motion data from this event offer invaluable information and opportunity; their unique features include very strong short-period spectral content, long duration, and effects due to local asperities as well as direction of rupture/wave propagation. Aiming at gaining useful experience from this tragic event, Earthquake Engineering Field Investigation Team (EEFIT) organised and dispatched a team to the Tōhoku region of Japan. During the EEFIT mission, ground shaking damage surveys were conducted in Sendai, Shirakawa, and Sukagawa, where the Japan Meteorological Agency intensity of 6+ was observed and instrumentally recorded ground motion data were available. The damage survey results identify the key factors for severe shaking damage, such as insufficient lateral reinforcement and detailing in structural columns from structural capacity viewpoint and rich spectral content of ground shaking in the intermediate vibration period range from seismic demand viewpoint. Importantly, inclusion of several ground motion parameters, such as nonlinear structural response, in shaking damage surveys, can improve the correlation of observed ground motion with shaking damage and therefore enhance existing indicators of potential damage.     

River Water Pollution in Developed and Developing Countries: Judge and Assessment of Physicochemical Characteristics and Selected Dissolved Metal Concentration

To compare water quality in rivers of developed and developing countries, a study based on physicochemical parameters and dissolved metals levels was conducted. Water samples were collected from selected sites in Dhaka, Bangladesh; Hokkaido and Osaka, Japan; Erdenet, Mongolia and West Java, Indonesia. Analysis of least significant differences revealed that most water quality parameters were within comparable low levels in both developed and developing countries. The dissolved metals concentrations were found to be similar and below those of water standards except for manganese and cadmium at every sampling point, and lead in Erdenet, Mongolia. Some metals showed high enrichment factors in the rivers of Osaka, Japan and Erdenet, Mongolia, indicating accumulation possibility of metals in the river‐bed sediments. High concentrations of dissolved organic carbon, Escherichia coli and dissolved metals suggested greater water pollution in some rivers of developing countries than in the rivers of Japan. Principal component analysis showed strong correlations between “dissolved organic carbon and chemical oxygen demand” and “conductivity and total dissolved solids” at each sampling point, and E. coli, nitrate (NO), nitrite (NO), and pH levels were found to be higher in the rivers of Dhaka and Erdenet. In addition, there were high levels of Al and Zn in West Java, Pb in Erdenet, and Mn, Fe, and Cr in the rivers of Dhaka and Japan. Based on pressures and impacts, it is evident that dissolved metal, organic, and fecal pollution in the rivers of developing countries are in somewhat dreadful condition in comparison with the rivers of developed country.     

On the X-ray image of the Crab nebula: comparison with Chandra observations

An axisymmetric model for the Crab nebula is constructed to examine the flow dynamics in the nebula. The model is based on that of Kennel & Coroniti, although we assume that the kinetic-energy-dominant wind is confined to an equatorial region. The evolution of the distribution function of the electron–positron plasma flowing out in the nebula is calculated. Given viewing angles, we reproduce an image of the nebula and compare it with the Chandra observation.
The reproduced image is not ring-like, but is rather 'lip-shaped'. It is found that the assumption of a toroidal field does not reproduce the Chandra image. We must assume that there is a disordered magnetic field with an amplitude as large as the mean toroidal field. In addition, the brightness contrast between the front and back sides of the ring cannot be reproduced if we assume that the magnetization parameter σ is as small as ∼10⁻³. The brightness profile along the semimajor axis of the torus is also examined. The non-dissipative, ideal-magnetohydrodynamic approximation in the nebula appears to break down.
We speculate that if the magnetic energy is released by some process that produces a turbulent field in the nebula flow and causes heating and acceleration – for example, by magnetic reconnection – then the present difficulties may be resolved (i.e. we can reproduce a ring image and a higher brightness contrast). Thus, the magnetization parameter σ can be larger than previously expected.