Scaling laws between seismo-electric/magnetic fields and earthquake magnitude

The mechanisms generating the charges/potentials and abnormal electromagnetic radiation that accompany earthquakes have been discussed based on observational, theoretical and laboratory studies, in particular over the last few decades. We previously conducted stick‐slip tests using precut granite cores with a contact electrode on the sample side, and proposed that surface charges released from charge trapping centres on sheared asperities are a possible source of the above‐mentioned charges or potentials. Here we discuss seismo‐electric and magnetic fields formed by the surface charges, and derive their scaling laws with the earthquake magnitude at a distance. According to our model, detectability of these fields at a point on the ground surface depends strongly on wet/dry condition at a fault zone (sheared asperities).     

Tsunami Assessment for Risk Management at Nuclear Power Facilities in Japan

The present study focuses on evaluation of the maximum and minimum water levels caused by tsunamis as risk factors for operation and management at nuclear power facilities along the coastal area of Japan. Tsunamis generated by submarine earthquakes are examined, basing literature reviews and databases of information on historical tsunami events and run-up heights. For simulation of water level along the coast, a numerical calculation system should be designed with computational regions covering a particular site. Also the calculation system should be verified by comparison of historical and calculated tsunami heights. At the beginning of the tsunami assessment, the standard faults, their locations, mechanisms and maximum magnitudes should be carefully estimated by considering historical earthquake-induced tsunamis and seismo-tectonics at each area. Secondly, the range of errors in the model parameters should be considered since earthquakes and tsunamis are natural phenomena that involve natural variability as well as errors in estimating parameters. For these reasons, uncertainty-induced errors should be taken into account in the process of tsunami assessment with parametric study of the tsunami source model. The element tsunamis calculated by the standard fault models with the errors would be given for the design. Then, the design tsunami can be selected among the element tsunamis with the most significant impact, maximum and minimum water levels, on the site, bearing in mind the possible errors in the numerical calculation system. Finally, the design tsunami is verified by comparison with the run-up heights of historical tsunamis, ensuring that the design tsunami is selected as the highest of all historical and possible future tsunamis at the site.     

Studying Air Pollution with Kitt Peak Solar Flux Atlas—Analysis Method and Results of Observation

l.Introducti0nTwoflightsoftheSAGEIIIinstrumentwereplanedbeinglaunchedinJune2O00byRussianMeteor-3Mandin2002byInternationalSpaceStation(ISS).Itisexpectedthattheywouldofferinformationofalmostglobalcoverage.Theseinstrumentswillutilizetheselfcal-ibratingsolaroccultationtechniquetomeasureprofilesofaerosoIextinctionfrom0to4Okm,ozonefrom6to85km,nitrogendioxidefroml0to5Okm,andwatervaporfrom0to5Okm,andutilizelunaroccultationobservati0nstomonitorthekeynighttimesPecies,nitrogentrioxidefrom22to55k…     

Application of the Information Criterion to the Estimation ofGalaxy Luminosity Function

To determine the exact shape of the luminosity function (LF) of galaxies is one of the central problems in galactic astronomy and observational cosmology. The most popular method to estimate the LF is maximum likelihood, which is clearly understood with the concepts of the information theory. In the field of information theory and statistical inference, great advance has been made by the discovery of Akaike's Information Criterion (AIC). It enables us to perform a direct comparison among different types of model swith different numbers of parameters, and provides us a common basis of the model adequacy. In this paper we applied AIC to the determination of the shape of the LF. We first treated the estimation using stepwise LF(Efstathiou, Ellis and Peterson,1988), and derived a formula to obtain the optimal bin number. In addition, we studied the method to compare the goodness-of-fit of the parametric form (Sandage, Tamman and Yahil, 1979) with stepwise LF. This revised version was published online in July 2006 with corrections to the Cover Date.     

Correlation study between suspended particulate matter and DOAS data

Continuous data of aerosol optical thickness monitored using differential optical absorption spectroscopy (DOAS) are correlated with the concentration of ground-measured suspended particulate matter (SPM). A high correlation is found between the DOAS and the ground SPM data, making it possible to calculate the mass extinction efficiency of the aerosols in the atmosphere. It is found that the value of mean mass extinction efficiency (MEE) varies over a range of 2.6–13.7m2 g?1, with smaller and larger values occurring for size distributions dominated by coarse and fine particles, respectively.     

Landfill development in the urban fringe of Metro Manila

In low-lying areas of urban and suburban regions in Asia, the use of landfill has allowed urban land use to encroach onto watery landforms, such as back marshes, which were formerly used as rice fields. To improve understanding of the associations between land-use patterns and landfill development, we carried out a case study in the urban fringe of Metro Manila in the Philippines. We examined landfill volume derived from land-use change using GIS, and field surveyed qualitative aspects of the landfill used. We calculated the rate of application of landfill in low-lying housing development areas to be 5.0 × 10³ m³ km^?2 year^?1, most of which consisted of offsite disposal of construction waste or crushed rock produced by urban development and renewal on the adjoining uplands. The flow of fill material from offsite sources to onsite landfill development areas was on the basis of individual agreements between suppliers and developers.     

Methane in Izena Cauldron,Okinawa Trough

Methane in the deep water of Izena Cauldron (maximum depth: ca. 1650 m) at the east side of mid-Okinawa Trough was studied by casting a CTD system with 12 Niskin bottles for water sampling at 11 stations inside and outside the cauldron. The water contained much methane up to 706 nmoles/l. The depths of maximum concentration varied widely from station to station, indicating the existence of a considerable number of vents emitting methane and heat. The waters containing less methane formed a straight line in theT-S diagram, while those containing more methane were more largely deviated from the line. The temperature anomaly was virtually proportional to the methane concentration, suggesting that the oxidation rate of methane inside the cauldron is negligibly small and methane can be used as a tracer of the cauldron water. The relation and the estimated vertical diffusivity gave the following fluxes. The emissions of methane and heat out of the bottom below 1450 m turn out to be 1400 moles/day and 7×10¹⁰ cal/day, respectively. The total emission rates inside the cauldron are presumed to be about twice the above values. The turnover time of methane has been estimated to be 240 days, which is also that of heat generated from the bottom and probably that of the bottom water.     

Effects of bottom topography and density stratification on variations of western boundary currents caused by periodic change in wind stress

Variations of the western boundary currents induced by a periodic change in wind stress are studied in a two-layer model with a continental slope along the western boundary. The variation of the total transport of the western boundary current over the continental slope shows a considerable phase lag with the wind stress and a decrease in amplitude compared with for the flat bottom ocean, though the interior barotropic response is to adjust almost instantaneously to the wind stress. The total transport variation of the western boundary current is well approximated by the upper layer transport variation. That is, almost complete separation of the upper- and lower-layer flows takes place over the slope, and only the upper layer flow contributes to the change in total transport of the western boundary current. Contributions of the interior barotropic and baroclinic responses to the upper layer transport variation depend on the forcing period. With decrease in the forcing period, the barotropic response becomes relatively important for determining the upper layer transport variation although the amplitude of the variation is smaller.