Tectono-metamorphic evolution of the Cretaceous Shimanto accretionary complex, central Japan: Constraints from a fluid inclusion analysis of syn-tectonic veins     

Hidetoshi  Hara  Ken-Ichiro  Hisada 《Island Arc》2007,16(1):57-68

Abstract   Micro-thermometry of water-rich fluid inclusions from two syn-tectonic veins sets ( D1 and D2 veins) in the Otaki Group, part of the Cretaceous Shimanto accretionary complex of the Kanto Mountains, central Japan reveals the following tectono-metamorphic evolution. Combining the results of microthermometric analyses of fluid inclusions from D1 veins with an assumed geothermal gradient of 20–50°C/km indicates that the temperature and fluid pressure conditions during D1 were 270–300°C and 140–190 MPa, respectively. Peak metamorphic conditions during the development of D2 slaty cleavage involved temperatures in excess of 300°C and fluid pressures greater than 270 MPa, based on analyses of microthermometry of water-rich fluid inclusions from the D2 vein and illite crystallinity. The estimated fluid pressure increased by approximately 80 MPa from D1 accretionary processes to metamorphism and slaty cleavage development during D2 . Assuming that fluid pressure reached lithostatic pressure, the observed increase in fluid pressure can be accounted for by thrusting of the Jurassic Chichibu accretionary complex over the Cretaceous Shimanto accretionary complex. Following thrusting, both accretionary complexes were subjected to metamorphism during the latest Cretaceous.  相似文献   

Simulating the carbon balance of a temperate larch forest under various meteorological conditions     

Motomu Toda  Masayuki Yokozawa  Akihiro Sumida  Tsutomu Watanabe  Toshihiko Hara 《Carbon balance and management》2007,2(1):1-18

This editorial provides a subject index from published articles, active researchers, and published papers in the field of carbon balance and management.  相似文献   

Behavior of gases in the Nojima Fault Zone revealed from the chemical composition and carbon isotope ratio of gases extracted from DPRI 1800 m drill core   总被引：2，自引：0，他引：2  

Takashi Arai  Tamotsu Okusawa  Hiroaki Tsukahara 《Island Arc》2001,10(3-4):430-438

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Inversion for laterally heterogeneous upper mantle S-wave velocity structure using iterative waveform inversion     

Tatsuhiko Hara  Seiji Tsuboi  Robert J. Geller 《Geophysical Journal International》1993,115(3):667-698

In contrast to previous work, which treats the Earth's lateral heterogeneity as an infinitesimal perturbation to a spherically symmetrical starting model, we conduct iterative linearized waveform inversion for the Earth's laterally heterogeneous structure. We use the Direct Solution Method (DSM) (Geller et al. 1990a) to calculate synthetic seismograms and their partial derivatives for a laterally heterogeneous earth model. We invert surface-wave data from the IDA and GEOSCOPE networks. We expand the lateral heterogeneity of rigidity in spherical harmonics up to angular order number 8 and use three parameters to specify the depth dependence of each harmonic, giving us a total of 240 unknowns. The short-wavelength lateral heterogeneity (s = 4, 6 and 8) in the deeper part of the upper mantle obtained by this study differs significantly from M84A. The relative improvement in the variance reduction as compared with model M84A is about 20 per cent for the IDA data and more than 100 per cent for the GEOSCOPE data.  相似文献   

Global mapping of urban built-up areas of year 2014 by combining MODIS multispectral data with VIIRS nighttime light data     

Ram C. Sharma  Ryutaro Tateishi  Keitarou Hara  Saeid Gharechelou  Kotaro Iizuka 《International Journal of Digital Earth》2016,9(10):1004-1020

An improved methodology for the extraction and mapping of urban built-up areas at a global scale is presented in this study. The Moderate Resolution Imaging Spectroradiometer (MODIS)-based multispectral data were combined with the Visible Infrared Imager Radiometer Suite (VIIRS)-based nighttime light (NTL) data for robust extraction and mapping of urban built-up areas. The MODIS-based newly proposed Urban Built-up Index (UBI) was combined with NTL data, and the resulting Enhanced UBI (EUBI) was used as a single master image for global extraction of urban built-up areas. Due to higher variation of the EUBI with respect to geographical regions, a region-specific threshold approach was used to extract urban built-up areas. This research provided 500-m-resolution global urban built-up map of year 2014. The resulted map was compared with three existing moderate-resolution global maps and one high-resolution map in the United States. The comparative analysis demonstrated finer details of the urban built-up cover estimated by the resultant map.  相似文献   

Ultra-rapid earth rotation determination with VLBI during CONT11 and CONT14     

Rüdiger Haas  Thomas Hobiger  Shinobu Kurihara  Tetsuya Hara 《Journal of Geodesy》2017,91(7):831-837

We present earth rotation results from the ultra-rapid operations during the continuous VLBI campaigns CONT11 and CONT14. The baseline Onsala–Tsukuba, i.e., using two out of the 13 and 17 stations contributing to CONT11 and CONT14, respectively, was used to derive UT1-UTC in ultra-rapid mode during the ongoing campaigns. The latency between a new observation and a new UT1-UTC result was less than 10 min for more than 95% of the observations. The accuracy of the derived ultra-rapid UT1-UTC results is approximately a factor of three worse than results from optimized one-baseline sessions and/or complete analysis of large VLBI networks. This is, however, due to that the one-baseline picked from the CONT campaigns is not optimized for earth rotation determination. Our results prove that the 24/7 operation mode planned for VGOS, the next-generation VLBI system, is possible already today. However, further improvements in data connectivity of stations and correlators as well in the automated analysis are necessary to realize the ambitious VGOS plans.  相似文献   

Enzymatic Approach to Fungal Association with Arthropod Guts: A Case Study for the Crustacean Host, Nihonotrypaea harmandi, and Its Foregut Fungus, Enteromyces callianassae     

Hiroshi Kimura  Kazuyuki Harada  Kenji Hara  & Akio Tamaki 《Marine Ecology》2002,23(2):157-183

Abstract. In the callianassid shrimp Nihonotrypaea harmandi (Bouvier 1901), the trichomycete fungus Enteromyces callianassae Lichtwardt 1961 occurs exclusively on the foregut lining. The enzymes from both the shrimp and the fungus apparently hydrolyze certain nitrogen and carbon compounds in detritus. The activities of various proteases and carbohydrases contained in the foregut juice were compared between fungus-infected shrimps collected from a sandflat in Kyushu, Japan (51 % infection rate) and uninfected shrimps from a nearby sandflat. The concentration of enzymatically hydrolyzable amino acids (EHAA) in sediment liberated by the foregut juice with fungi was slightly lower than that by 0.1 mg·ml^-1 proteinase-K and significantly higher than that by the foregut juice without fungi. In both foregut juices, substantial enzyme activities were recorded for proteinase(s), peptidases, amylase, cellulase and β-1,3-glucanase, and minimal ones for maltase and cellobiase. Of the commercial substrates examined, only in the case of the mixture of 16 kinds of dipeptides was a significantly higher enzyme activity in the foregut juice with fungi observed. In the process of EHAA liberation from sediment, peptidases secreted by the fungus most probably act as a supplement to the endogenous secretion by the shrimp. This may explain the higher shrimp growth rate recorded for the population with fungi. However, the significantly higher sediment EHAA concentration of the sandflat inhabited by this population versus the population without fungi could be another crucial factor explaining the site difference in shrimp growth rate.  相似文献   

Does the water retained in a filter paper affect the chlorophylla measurement?     

Chen  Yuh-Ling Lee  Hara  Shigemitsu 《Journal of Oceanography》1994,50(2):165-171

The present study investigated the effects of water seeped in a filter paper on the variations of chlorophylla measurement. As little as 184 l water retained in a 25 mm diameter GF/F filter paper after filtration resulted in the settlement of 60% chlorophylla at the bottom 20% of the extractant (90% acetone) in the extraction tube. More than one order difference in concentration of chlorophylla was found between the uppermost 20% and the bottom 20% of the extractant. Chlorophylla is trapped at the bottom by a pycnocline created by the water seeped into the filter paper and by chlorophylla itself, which is heavier than the extractant. Once the extractant was well mixed, good reproducibility of measurement was obtained. White precipitation occurred during the mixing of seawater sample and the extractant and was not found to affect the measurement of chlorophylla. The dilution of the extractant by the seawater seeped in the filter paper during extraction probably did not affect the extraction efficiency.  相似文献   

Hydrographic profiling across the East China sea shelf edge by an underwater sliding vehicle with CTD sensors     

Yoshifumi Kuroda  Toshiaki Hara  Atsunobu Misumi  Gentaro Kai  Jun Suwa 《Progress in Oceanography》1988,21(3-4)

Temperature, salinity and density structures were observed on Sept. 23 and 24, 1986 at one vertical section across the East China Sea shelf edge by an advanced type of towed vehicle with CTD sensors which was developed by the Japan Marine Science and Technology Center. The vehicle was towed at a speed of 2.5 m s⁻¹ down to 150 m depth and at intervals of 170–500 m width. The observed profile was 50 km long on Sept. 23 and 70 km long on Sept. 24 along the cross-shelf section. An on-ship acoustic Doppler current profiler was simultaneously used to measure current velocities at depths of 20, 50 and 100 m.Interesting features were noticed. Firstly, there was a vertical displacement of pycnoclines at the lower edge of the surface mixed layer accompanied by vertical inversion of the salinity and temperature in the vicinity of the shelf edge. Pycnoclines were displaced upward by 12 m toward the outer edge on Sept. 23 and by 20 m on Sept. 24. On Sept. 23, the salinity inversion took place in a layer 20 m thick and 8 km wide, whereas the temperature inversion took place in a layer 8 m thick and 1.5 km wide. These vertical inversions were probably generated by vertical shear of tidal currents which was observed by the Doppler current profiler. These results throw light on understanding the vertical mixing process of stratified water on the continental shelf edge. Secondly, an intrusion of the shelf water into the Kuroshio water was observed along pycnoclines below the surface mixed layer 60 to 70 m deep in the Kuroshio region outer break. The measurement was successful in showing a horizontal mixing process of the shelf water and the Kuroshio water which could not be found out by standard CTD observations.  相似文献   

The Characteristics of Solar X-Class Flares and CMEs: A Paradigm for Stellar Superflares and Eruptions?     

Louise K. Harra  Carolus J. Schrijver  Miho Janvier  Shin Toriumi  Hugh Hudson  Sarah Matthews  Magnus M. Woods  Hirohisa Hara  Manuel Guedel  Adam Kowalski  Rachel Osten  Kanya Kusano  Theresa Lueftinger 《Solar physics》2016,291(6):1761-1782

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