Quartz microstructures and deformation conditions in the Hatagawa shear zone, north-eastern Japan

Abstract Meso- and microscale structural analyses were carried out in the Hatagawa shear zone, north-eastern Japan. The shear zone is a sinistral strike–slip ductile shear zone, and has a 1-km wide north-south trending region where quartz mean grain size of approximately 35 μm does not vary significantly. Two types of quartz microstructures, A and B, occur in the western and eastern part of the shear zone, respectively. The lattice preferred orientation (LPO) patterns are characterized by a type I crossed girdle in the samples with the quartz microstructure A, and a Y maximum in the samples with the quartz microstructure B. The microstructures under optical and transmission electron microscopes indicates that the quartz recrystallization occurred predominantly by progressive subgrain rotation in microstructure A, and by both progressive subgrain rotation and grain boundary migration in microstructure B. This suggests different deformation conditions in the western and eastern parts of the shear zone. Quartz LPO patterns, presence of myrmekite, feldspar compositions, and dislocation density also suggest difference in the deformation conditions. The syn-deformation temperature in the western part of the shear zone was lower than that of the eastern part of the shear zone. The stress in the western part of the shear zone was higher than that of the eastern part of the shear zone. The difference in the deformation conditions would affect not only the quartz microstructure, but also the quartz LPO patterns and the presence of myrmekite around K-feldspar porphyroclasts.     

Building Damage and Casualties after an Earthquake

The relationship between building damage patterns and human casualties in Nishinomiya City – one of the most heavily damaged cities in the 1995 Hanshin-Awaji Earthquake Disaster – was investigated using photographs of damaged buildings. First, the photographs of buildings in which casualties occurred were identified, and the building damage patterns were judged based on the photographs considering the existence of survival space. Then the relationship between the building damage pattern and casualty occurrence, and the characteristics of casualty distribution, were investigated. The main findings were as follows: Most casualties occurred in relatively old two-story wooden buildings in which the ground floor completely collapsed without survival space; casualties occurred at all building damage levels including ``no damage', and it can be seen that building damage is the major, but not the sole cause, of casualties in an earthquake; in Nishinomiya City, the regional distributions of casualties due to the collapse of buildings that left no survival space is similar to that of casualties due to other types of building damage.     

High molecular weight organic matter in seawater

The presence and nature of high molecular weight organic matter in seawater was critically reviewed and its biogeochemical cycle was discussed.Organic matter that passes through a filter of 0.5–1 μm pore size is called dissolved and that which does not pass through such a filter is defined as particulate. The size of colloidal particles ranges from 0.001 to 1 μm, and therefore, they are included in the dissolved fraction having high molecular weight.High molecular weight organic matter greater than 100,000 molecular weight was found in the seawater of Tokyo Bay. The values ranged from 0.1 to 1.5 mgC/l, and accounted for 8–45% of the total dissolved organic matter.Decomposition experiments on dissolved organic matter showed that macromolecular organic matter is refractory to bacterial attack. However, macromolecular organic materials tend to aggregate or adsorb on small particles to a sufficient size for precipitation. Organic aggregates thus formed sink to the bottom of the sea and bioelements included in them are removed from water column. High molecular weight organic materials are, therefore, considered to play an important role in transportation and distribution of matter in seawater.In order to elucidate the chemical and biological properties of macromolecular organic matter, concentration and isolation of this material are important, using methods such as adsorption on organic adsorbents or ultrafiltration.     

Consideration of natural hazards in the design and risk management of industrial facilities

Recent chemical accidents precipitated by natural disasters have prompted governments in the United States, Japan, and Europe, among other countries, to re-evaluate current practices in the design and risk management of industrial facilities. This paper presents an overview of natural hazard design considerations and external events risk management requirements in the industrial sector, with particular emphasis on industrial practices in the United States, Japan, and Europe. The analysis shows that although regulations exist to ensure industrial plant structures are built to resist natural hazards (up to the design level), there are few laws to address the performance of non-structural elements and safety and emergency response measures during a natural disaster. Laws usually also refer to natural hazards only indirectly, and provisions to prevent or respond to simultaneous disasters from single or multiple sources concurrent with the natural disaster are usually not present.

Origin of hybrid ferrolatite lavas from Magic Reservoir eruptive center,Snake River Plain,Idaho

The mineralogy and geochemical characteristics of intermediate composition ferrolatites and related lavas from the Magic Reservoir eruptive center (central Snake River Plain) have been investigated to evaluate the origin and petrologic significance of these hybrid lavas. The ferrolatites are chemically uniform, but contain a disequilibrium phenocryst/xenocryst assemblage derived in part from mixed rhyolitic and basaltic magmas that are closely represented by extrusive units in the area. The hybrid lavas also contain xenoliths of Archean granulites and have high ⁸⁷Sr/ ⁸⁶Sr and low ¹⁴³Nd/¹⁴⁴Nd ratios, all of which suggest significant magma-crust interaction. Quantitative models including magma mixing, minor crystal fractionation, and crustal contamination very closely reproduce the observed compositions of these ferrolatites; closed system fractionation and (or) simple bulk contamination models are not as successful and can be ruled out. It appears that preexisting mafic and silicic magmas from distinct sources (e.g., mantle and crust) encounter one another in crustal-level magma chambers under conditions where intimate mixing may occur despite wide differences in the physical properties of these liquids.     

Phytoplankton community reorganization driven by eutrophication and warming in Lake Biwa

We compiled and analyzed long-term data, including chemical, physical and phytoplankton community data, for the Lake Biwa ecosystem from 1962 to 2003. Analyses on environmental data indicate that Lake Biwa had experienced intensified eutrophication (according to total phosphorus concentration) in the late 1960s and returned to a less eutrophic status around 1985, and then exhibited rapid warming and thus increased water column stability since 1990. Total phytoplankton cell volume largely followed the trend of total phosphorus concentration, albeit short-term fluctuations existed. However, phytoplankton community shifted dramatically in response to those changes of environmental states. These shifts were cause by changes in trophic status driven by phosphorus loadings and physical properties in the water column driven by warming. Moreover, most phytoplankton species did not show a strong linear correlation with environmental variables, suggesting nonlinear transitions among different states.     

Continuous Observation of Groundwater and Crustal Deformation for Forecasting Tonankai and Nankai Earthquakes in Japan

In 2006, we started construction of an observation network of 12 stations in and around Shikoku and the Kii Peninsula to conduct research for forecasting Tonankai and Nankai earthquakes. The purpose of the network is to clarify the mechanism of past preseismic groundwater changes and crustal deformation related to Tonankai and Nankai earthquakes. Construction of the network of 12 stations was completed in January 2009. Work on two stations, Hongu-Mikoshi (HGM) and Ichiura (ICU), was finished earlier and they began observations in 2007. These two stations detected strain changes caused by the slow-slip events on the plate boundary in June 2008, although related changes in groundwater levels were not clearly recognized.     

Analysis software for upper atmospheric data developed by the IUGONET project and its application to polar science

To comprehensively understand the Arctic and Antarctic upper atmosphere, it is often crucial to analyze various data that are obtained from many regions. Infrastructure that promotes such interdisciplinary studies on the upper atmosphere has been developed by a Japanese inter-university project called the Inter-university Upper atmosphere Global Observation Network （1UGONET）. The objective of this paper is to describe the infrastructure and tools developed by IUGONET. We focus on the data analysis software. It is written in Interactive Data Language （IDL） and is a plug-in for the THEMIS Data Analysis Software suite （TDAS）, which is a set of IDL libraries used to visualize and analyze satellite- and ground-based data. We present plots of upper atmospheric data provided by IUGONET as examples of applications, and verify the usefulness of the software in the study of polar science. We discuss IUGONET＇s new and unique developments, i.e., an executable file of TDAS that can run on the IDL Virtual Machine, IDL routines to retrieve metadata from the IUGONET database, and an archive of 3-D simulation data that uses the Common Data Format so that it can easily be used with TDAS.     

Distribution of petroleum hydrocarbons in soils and the underlying unsaturated subsurface at an abandoned petrochemical site,North China

Contamination characteristics of petroleum hydrocarbons in soils and the underlying unsaturated subsurface were analysed by investigating and sampling at different depth of five boreholes named SH1 through SH5 at a typical petrochemical site, North China. Topsoil volatile organic gas measurement revealed that SH‐3 was the center of one pollution plume. Soil samples analysis showed that aromatic hydrocarbons and chlorinated hydrocarbons were major pollutants. Their maximum concentration was found at 6.5 and 14.6 m of SH‐2, 13 m of SH‐5, and 18.5 m of SH‐3. These pollutants are mostly accumulated on the interface between two different lithological layers, especially between the sand and silt clay layers. Denitrifying and iron reducing were main biogeochemical processes in this site. Under the influence of groundwater level fluctuation, free NAPLs passed through the boundary and dissolved into the lower groundwater. Knowledge of these associations between contaminant distributions and affecting factors could have implications for soil and groundwater pollution prevention and control. Copyright © 2013 John Wiley & Sons, Ltd.     

Dynamic non-linear analysis of reinforced concrete shear wall by finite element method with explicit analytical procedure

A numerical procedure for a dynamic non-linear finite element analysis is proposed here to analyse three-dimensional reinforced concrete shear wall structures subjected to earthquake motions. A shear wall is modelled as a quasi-three dimensional structure which is composed of plane elements considering the in-plane stiffness of orthogonal flange panels. The proposed constitutive model is based on the non-linearity of reinforcement and concrete in which the tension stiffening in tension and the degradation of stiffness and strength in compression of concrete after cracking are considered. The acceleration-pulse method, which is a kind of explicit analytical procedure, is employed to solve the non-linear dynamic equations, where the dynamic equation can be solved without stiffness matrix and so the iterative procedure is not necessary for descending portion of stress–strain relationship caused by cracking and softening after compressive strength in concrete. The damping effect is considered by assuming equivalent viscous damping which can give good cyclic behaviours of inertia force vs. displacement relationships. This analytical method was applied to a test specimen of a reinforced concrete shear wall with a H-shaped section which was vibrated up to failure by using a large-scale shaking table with high -performance in Japan. The test was performed as one of the dynamic model tests for evaluation of seismic behaviour of nuclear reactor buildings. The calculations were performed sequentially from the elastic range to failure. The comparison with the test results shows that this approach has good accuracy. © 1997 by John Wiley & Sons Ltd