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.     

Laser-Dye Imaging of the pH Field in a Laboratory Experiment

We established a precise DeLIF (Dual Emission Laser Light Fluorescence) system for the instant measurement of the pH field in laboratory experiments. This method is very important in studies of the biological impacts of CO₂ sequestration, i.e., effects of pH on organisms. The technique is demonstrated by applying it to the pH measurement around a liquid CO₂ droplet, which has a large gradient of CO₂ concentration near its interface, the concentration value on the boundary being known as the solubility of CO₂. In the Laser Induced Fluorescence (LIF) method using quinine and an ultraviolet laser light source, the relatively unstable pulse of the laser source decreased the measurement reliability. We therefore investigated many kinds of fluorescent dye and demonstrated the DeLIF measurement, identifying a process for cancelling fluctuations of laser light intensity. Quinine and sulforhodamine were used as fluorescence dyes. The molar absorption coefficient and emission intensity of quinine depend on the pH of aqueous solutions, while those of sulforhodamine are not as much affected by pH. The ratio of these fluorescence intensities represents pH at each point of the image. As a result, the pH field was successfully measured with an uncertainty of only approximately ±0.005, for 3.0 < pH. This revised version was published online in July 2006 with corrections to the Cover Date.     

Flow of reinjected water and transmissibility distribution estimated by a tracer test in Otake Geothermal Reservoir, Japan

In order to estimate the distribution of pressure and transmissibility in the Otake Geothermal Reservoir, in which flow can be assumed to be two-dimensional and horizontal, well-head pressure and flow rates measured at both production and reinjection wells, and the time required for a tracer to arrive at certain production wells from one of the reinjection wells were analyzed. Analysis of these data was performed by means of an equation which was obtained by combining the Darcy and the continuity equations, in which the transmissibility and two components of the flow remain unknown. Estimation of pressure and transmissibility distributions and flow patterns within the reservoir was possible by numerical solution of this equation using the finite-difference method and by assuming suitable boundary conditions.     

Detection and accuracy of landslide movement by InSAR analysis using PALSAR-2 data

Interferometric synthetic aperture radar (InSAR) analysis is a radar technique for generating large-area maps of ground deformation using differences in the phase of microwaves returning to a satellite. In recent years, high-resolution SAR sensors have been developed that enable small-scale slope deformation to be detected, such as the partial block movement of a landslide. The L-band SAR (PALSAR-2) is mounted on Advanced Land Observing Satellite-2 (ALOS-2), which was launched on 24 Mar. 2014. Its main improvements compared with ALOS are enhanced resolution of as high as 3 m with a high-frequency recurrence period (14 days). Owing to its high resolution and the use of the L-band, PALSAR-2 can obtain reflective data passing through a tree canopy surface, unlike the other synthetic aperture radars. Therefore, the coherence of InSAR in mountainous forest areas is less likely to decrease, making it advantageous for the extraction of slope movement. In this study, to verify the accuracy of InSAR analysis using PALSAR-2 data, we compared the results of InSAR analysis and the measurement of the displacement in a landslide by global navigation satellite system (GNSS) observation. It was found that the average difference between the displacements obtained by InSAR analysis and the field measurements by GNSS was only 15.1 mm in the slant range direction, indicating the high accuracy of InSAR analysis. Many of the areas detected by InSAR analysis corresponded to the locations of surface changes due to landslide activity. Additionally, in the areas detected by InSAR analysis using multiple datasets, the ground changes due to landslide movement were confirmed by site investigation.     

Variability in the Relative Penetration of Ultraviolet Radiation to Photosynthetically Available Radiation in Temperate Coastal Waters, Japan

UVR and PAR wavelengths are attenuated to different extents within the water column, causing variations in spectral composition with depth. The present investigation (a) describes the variability of UVR and PAR penetration at a station in the temperate coastal waters of Sagami Bay and determines (b) the characteristics of relative UVR penetration to the euphotic zone. Examination of the seasonal irradiance profile measurements indicated eight measurements displaying two distinct attenuation coefficients (K _d) for specific UVR wavelengths and PAR. The two attenuation coefficients observed from specific wavelengths in the water column may be caused not only by chlorophyll pigments, but also by dissolved organic material in the upper layer. The 1% depth of surface UVR at 305, 320, 340, and 380 nm averaged 10.8 ± 5.7, 14.9 ± 9.5, 19.8 ± 12.1, and 30.4 ± 17.6 m, respectively. The depth of euphotic layer displayed less variability averaging 62 ± 15 m throughout the entire study. Relative UVR penetration within the euphotic zone averaged 17.8 ± 8.1, 22.9 ± 10, 30.5 ± 13.8, and 46 ± 46.9% for 305, 320, 340, and 380 nm, respectively. A large variation of the relative transmission of UVR within the euphotic zone was found although the spectral composition was relatively stable in the air throughout the study.     

Stratigraphic records of tsunamis along the Japan Sea,southwest Hokkaido,northern Japan

The stratigraphy of tsunami deposits along the Japan Sea, southwest Hokkaido, northern Japan, reveals tsunami recurrences in this particular area. Sandy tsunami deposits are preserved in small valley plains, whereas gravelly deposits of possible tsunami origin are identified in surficial soils covering a Holocene marine terrace and a slope talus. At least five horizons of tsunami events can be defined in the Okushiri Island, the youngest of which immediately overlies the Ko‐d tephra layer (1640 AD) and was likely formed by the historical Oshima‐Ohshima tsunami in 1741 AD. The four older tsunami deposits, dated using accelerator mass spectrometry ¹⁴C, were formed at around the 12th century, 1.5–1.6, 2.4–2.6, and 2.8–3.1 ka, respectively. Tsunami sand beds of the 1741 AD and circa 12th century events are recognized in the Hiyama District of Hokkaido Island, but the older tsunami deposits are missing. The deposits of these two tsunamis are found together at the same sites and distributed in regions where wave heights of the 1993 tsunami (Hokkaido Nansei‐oki earthquake, Mw = 7.7) were less than 3 m. Thus, the 12th century tsunami waves were possibly generated near the south of Okushiri Island, whereas the 1993 tsunami was generated towards the north of the island. The estimated recurrence intervals of paleotsunamis, 200–1100 years with an average of 500 years, likely represents the recurrence interval of large earthquakes which would have occurred along several active faults offshore of southwest Hokkaido.     

浙江苍南瑶坑碱性花岗岩的地球化学及其成因类型

瑶坑岩体位于浙闽交界的苍南县马站镇北侧,侵入于早白垩世石帽山群下组地层中。岩石发育典型的文象结构和晶洞 构造,含有特征的钠铁闪石碱性铁镁矿物,主要矿物组合为石英＋条纹长石＋钠铁闪石＋黑云母＋萤石、锆石。化学成分上,该岩体富硅、碱、贫钙、镁,分异指数和氧化指数高,富Ｒｂ、Ｔｈ、Ｇａ,贫Ｓｒ、Ｂａ,Ｇａ／Ａｌ比值大,富轻稀土,Ｎｂ、Ｚｒ、Ｈｆ等高场强元素含量高,Ｃｒ、Ｃｏ、Ｎｉ、Ｖ等过渡族元素显著亏损