Supervised landform classification of Northeast Honshu from DEM-derived thematic maps

This paper proposes a quantitative method to classify landforms using four morphometric parameters from DEM-derived thematic raster maps of slope and topographic openness. Because the different surficial processes and stages in the evolution of slopes create landscapes with different shapes, these parameters may lead to a genetic interpretation of topography. The raster maps of slope and topographic openness were constructed for Northeast Honshu, Japan, from 50-m DEMs. The mean and standard deviation of morphometric parameters within a 3050 m by 3050 m moving window on the raster maps were calculated. The results for some training areas show that constructional/depositional and erosional landforms with different relief have different morphometric characteristics. A supervised landform classification for Northeast Honshu using the knowledge from the training areas revealed a ladder geomorphological structure composed of high mountains, ranges and volcanoes. The close relationship between the ladder geomorphological structure and volcano distribution indicates that the structure reflects the magmatic plumbing system from the upper mantle to the crust of the Northeast Honshu arc.     

Progress in optical dating of guano-rich sediments associated with the Deep Skull, West Mouth of the Great Cave of Niah, Sarawak, Borneo

The West Mouth of the Great Cave of Niah is one of the major archaeological sites in Southeast Asia; the radiocarbon chronology of this site currently places the earliest presence of Homo sapiens (a Deep Skull find) in Southeast Asia at about 45 ka BP. An optical dating programme using sand-sized quartz was initiated in the West Mouth to complement the radiocarbon chronology. This paper reports on the progress in dating a key sample (sample 376r) that was taken from deposits containing the Deep Skull. A somewhat novel procedure was developed to separate and clean quartz grains from the unusual guano-rich deposits. From this, only a small quantity of quartz grains could be recovered and 36 aliquots (1 mm in diameter) were prepared, each consisting of 80 grains. This sample was dated by means of the single-aliquot regenerative-dose (SAR) method using the protocols of Murray and Wintle [2000. Luminescence dating of quartz using an improved single-aliquot regenerative-dose protocol. Radiation Measurements 32, 57–73], and of Choi et al. [2003. Luminescence dating of well-sorted marine terrace sediments on the southeastern coast of Korea. Quaternary Science Reviews 22, 407–421]. The results showed a wide distribution of equivalent doses; this distribution is inferred to be due to bioturbation, variable bleaching at deposition, and to local variations in the dose rate within the sample site. Dose rates were measured using both field (in-situ γ-ray spectrometry, IGRS) and laboratory (inductively coupled plasma mass spectrometry/atomic emission spectrometry, ICP-MS/AES; and isotope dilution, ID) methods. There was significant disagreement between the concentrations of radioisotopes found using laboratory and field measurements, indicating sediment heterogeneity and also possible disequilibrium in the ²³⁸U decay chain. Future work in the West Mouth should therefore concentrate on taking sediment samples of at least 500–600 cm³, improving the dose rate estimates (e.g. by high-resolution γ-ray spectrometry) and investigating other luminescence signals (e.g. red thermoluminescence) as potential geochronometers.     

Full-scale structural monitoring using an integrated GPS and accelerometer system

Accurate in situ measurement of the full-scale structural responses, especially tall buildings, under severe loading conditions is an important requirement for validating their design, evaluating their construction as well as facilitating their maintenance. Traditionally such response has been measured using accelerometers. However, it is impossible to measure the static and quasi-static components of motion with acceleration sensors. An integrated system comprising of RTK-GPS and accelerometers has been developed with the objective of assessing full-scale structural responses by exploiting the complementary characteristics of GPS and accelerometer sensors. The data used in this paper were obtained from GPS and accelerometer sensors installed on a 108-m-high steel tower in Tokyo, together with other sensors such as anemometer and strain gauge. The seismic and wind-induced responses of the tower were analyzed using the Fast Fourier Transformation (FFT) and compared to results from finite element modeling (FEM). In order to study the system reliability, the correlated signals were extracted by applying a digital filtering technique. Then the filtered data sets were converted to displacement (in the case of accelerometer data) and acceleration (in the case of GPS data) through double integration and double differentiation, respectively, for the purpose of direct comparison and to further fuse data from the two different sensors. The results agree with each other very well, although the static and quasi-static components are missing from the accelerometer-derived results. The redundancy of the monitoring system therefore has been achieved.     

Development of air conditioning technologies to reduce CO2 emissions in the commercial sector

Background  

Architectural methods that take into account global environmental conservation generally concentrate on mitigating the heat load of buildings. Here, we evaluate the reduction of carbon dioxide (CO₂) emissions that can be achieved by improving heating, ventilating, and air conditioning (HVAC) technologies.     

Strain geometries in the Sanbagawa Metamorphic Belt inferred from deformation structures in metabasite

Abstract Ductile deformation in the Sanbagawa Metamorphic Belt has been considered to be characterized by uniaxial elongation parallel to the east–west‐trending lineation, based on strain analysis of radiolarian fossils in metachert. However, only limited data were available to test this idea in strongly recrystallized schists. Strain measurements on deformed pillow structures in central Shikoku show uniaxial flattening, whereas pressure shadows around pyrite in the Kanto Mountains indicate constrictional strain. In addition, in the low‐grade part of the Sanbagawa Metamorphic Belt belonging to the Northern Chichibu Belt in the Kanto Mountains, deformed amygdules in pillow lava show flattening strain, which is consistent with the results of strain measurements using radiolarian fossils in the same area. These observations, together with the results of other strain analyses reported so far, indicate that the strain field is not uniform and that the east–west‐trending shearing and stretching were not pervasive in the Sanbagawa Metamorphic Belt.     

Differentation of magmatic emanation

Chemical properties of magmatic emanation can be estimated roughly by i) volatiles from rocks by heating at various temperatures, ii) volcanic emanations, iii) residual magmatic emanations, iv) calculation from chemical equilibrium between volatile matters and magmas. Magmatic emanation is assumed to consist all of the volatile matters in magmas such asH ₂ O, HCl, HF, SO ₂ H ₂ S, H ₂,CO 2,N ₂ and others (halides, etc.) at about 1200°C, although various kinds of magmatic emanations can be formed at different conditions. Magmatic emanation separated from magmas will change their chemical properties by many factors such as changes of temperature and pressure (displacement of chemical equilibrium), and reactions with other substances and it will differentiate into volcanic gases, volcanic waters, volcanic sublimates, and hydrothermal deposits (hot spring deposits). At temperatures above the critical point of water, separation of solid phase (sublimates), liquid phase, and displacement of chemical equilibrium may take place, and gaseous phase will gradually change their chemical properties as will be seen at many fumaroles. Chloride, hydrogen, andSO ₂ contents will gradually decrease along with lowering temperature. Once aqueous liquid phase appears below the critical point of water, all the soluble materials may dissolve into this hydrothermal solution. Consequently, the gaseous phase at this stage must have usually a little hydrogen chloride as is observed at many fumaroles. Aqueous solutions must be of acidic nature by dissolution of acid forming components, and by hydrolysis (Chloride type). When a self-reduction-oxidation reaction of sulfurous acid takes place, an aqueous solution of sulfate type will be formed. At this stage, solid phases consist of the remained sublimates which are difficultly soluble in aqueous solution, and deposits formed by reaction in the hydrothermal solutions. The gaseous phases below the boiling point of water, have usually a little water, and consist mainly ofCO ₂ type,H ₂ S type,N ₂ type, and mixed type owing to elimination or addition of components by reactions with waters or wall rocks according to their geological conditions. Aqueous solutions which was of acidic nature must be changed into alkaline solutions by reaction with wall rocks for a long time. When the oxidation of sulfur compounds takes place, an aqueous solution of sulfate type will be formed. Hydrogen sulfide type of water will be formed by reaction of sulfides with acid waters or absorption of hydrogen sulfide. Carbonate type of water will be formed whenCO ₂ is absorbed. Solid phases at this stage consist usually of hydrothermal deposits except for that at solfatara or mofette. The course of differentiation of magmatic emanation could take place in more complicated ways than that of magmatic differentiation.     

Disaster prevention,disaster preparedness and local community resilience within the context of disaster risk management in Cameroon

This paper presents a simulation of three components of near-field ground shaking recorded during the main shock at three stations of the September 16, 1978, Tabas (M _w = 7.4), Iran, earthquake, close to the causative fault. A hybrid method composed of a discrete wavenumber method developed by Bouchon (Bouchon in Bull Seismol Soc Am 71:959–971, 1981; Cotton and Coutant in Geophys J Int 128:676–688, 1997) and a stochastic finite-fault modeling based on a dynamic corner frequency proposed by Motazedian and Atkinson (Bull Seismol Soc Am 95:995–1010, 2005), modified by Assatourians and Atkinson (Bull Seismol Soc Am 97:935–1949, 2007), is used for generating the seismograms at low (0.1–1.0 Hz) and high frequencies (1.0–20.0 Hz), respectively. The results are validated by comparing the simulated peak acceleration, peak velocity, peak displacement, Arias intensity, the integral of velocity squared, Fourier spectrum and acceleration response spectrum on a frequency-by-frequency basis, the shape of the normalized integrals of acceleration and velocity squared, and the cross-correlation with the observed time-series data. Each characteristic is compared on a scale from 0 to 10, with 10 being perfect agreement. Also, the results are validated by comparing the simulated ground motions with the modified Mercalli intensity observations reported by reconnaissance teams and showed reasonable agreement. The results of the present study imply that the damage distribution pattern of the 1978 Tabas earthquake can be explained by the source directivity effect.     

Development of Taprang landslide,West Nepal

This paper is about a large landslide located at Taprang, on the right bank of the Madi River in the west Nepal Himalaya. It attempts to reconstruct the evolution of the landslide from its initial state to the present conditions. Many large landslides involve multiple failure incidents in different times to attain their present size and shape. The Taprang landslide has also been active for more than 75 years and experienced many failure episodes. The slide lies in a very complex geological setting characterized by the presence of Main Central Thrust and some other folds as well as several joint sets and shear zones. It is developed on weathered graphitic schists, highly fractured and jointed quartzites, marbles, gneisses, and a few amphibolites. Landslide mapping revealed that the rocks are deformed and fractured. They have also undergone intense weathering. Laboratory analysis of rock and soil samples collected from the landslide and surrounding area shows that the weathered rocks, joint infillings, and shear zones are rich in clay minerals, especially smectite and montmorillonite having swelling properties. Besides, hydrologic, climatic, and anthropogenic factors operating simultaneously since a long time have also contributed significantly to the enlargement of the slide. The study indicates that the landslide has a high potential of future enlargement towards upper slopes.     

Use of Statistical Models to Analyze Periodic Seismicity Observed for Clusters in the Kanto Region, Central Japan

—A periodic pattern of seismicity has been reported for the Kinugawa cluster in the Kanto region, where several earthquake clusters are observed at depths between 40 and 90 km. To analyze this periodicity, statistical studies are performed for the Kinugawa cluster together with eight other clusters. Hypocentral parameters of the earthquakes with magnitudes 4.5 and larger for the period between 1950 and 1995 are taken from the JMA catalogue. The simple sinusoidal function, the exponential of sinusoidal function and the stress release model are applied as the intensity function. Model parameters are determined by the maximum likelihood method and the best model for each cluster is selected by using the Akaike Information Criterion (AIC). In six cases the sinusoidal model or the exponential of the sinusoidal model is selected as the best option and achieves AIC reductions of values between 2.4 and 13.2 units from the simple Poisson model. The stress release model is selected for two clusters. The three clusters, the Kinugawa, Kasumigaura, and Choshi clusters, have a similar optimal period of about 10 years, and align in the northwest–southeast direction at a similar depth range of 40 to 70 km. A model modified from the stress release model is applied to the three clusters so to analyze the relationship among them. In the modified model, an earthquake occurrence in one zone increases the stress in the other zone, which is different from the original stress release model which assumes a linear increase with time. Applying the modified model to the Kinugawa cluster, an AIC reduction from the Poisson model is significantly larger than the value obtained with the sinusoidal model. This suggests that the periodic seismicity observed for the Kinugawa cluster can be explained with the more comprehensive model than the sinusoidal model.