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11.
Terumoto Kiyomine Tsuchiya Yoriko Otagiri Rie Nakabayashi Hironobu Nakabayashi Itsuki 《Natural Hazards》2022,110(2):1061-1081
Natural Hazards - In the aftermath of a disaster, the recovery process has long-term, multi-dimensional, and interactive aspects. To clarify the recovery conditions and victims’ perceptions... 相似文献
12.
In agricultural areas, fertilizer application is the main source of nitrate contamination of groundwater. To develop fertilizer
management strategies to combat this problem, arable land in Hokkaido, Japan was evaluated using geographic information system
techniques for intrinsic groundwater vulnerability to nitrate contamination. The DRASTIC method was modified to adapt it to
the Hokkaido environment and used for the evaluation. Of the seven original DRASTIC factors, the depth to water (D), net recharge
(R), soil media (S), topography (T), and impact of vadose zone media (I) were selected and used to explain the vertical movement
of contaminants to the aquifer. The rating for the net recharge factor was also modified to a dilution factor for contaminants,
rather than as a transporter. The frequency of wells with nitrate concentrations exceeding the Japanese environmental standard
(10 mg/L) was reasonably explained by vulnerability evaluation results (GLM: logit-link, quasi-binomial distribution, Y = [1 + exp(6.873765 − 0.045988 × X)]−1, p < 0.001). However, in the paddy fields and pastures, vulnerability did not exhibit a clear relationship with the frequency
of wells exceeding the standard. This suggests that the modified DRASTIC method is applicable for fertilizer application management
in upland fields. In addition, under the ongoing policy for acreage allotment for rice production, this method will be useful
for deciding the arrangement of arable land and crop rotation taking into consideration the potential risk of fertilizer-induced
nitrate contamination of groundwater. 相似文献
13.
ValéRie?DauxEmail author Christophe?LéCuyer FréDéRic?Adam Fran?Ois?Martineau Fran?Oise?Vimeux 《Climatic change》2005,70(3):445-464
In order to study climate variations during the last 1700 years in eastern France, fifty-eight oxygen isotope compositions of phosphate were measured in human tooth enamel. The individuals, who lived in Lorraine, are assumed to have drunk local water derived directly from rainfall. According to previous work, drinking water is the main source of oxygen that sets the isotopic composition of phosphatic tissues in humans. The empirical fractionation equation determined from our data combined with those of Longinelli’s one [Geochim. Cosmochim. Acta 48 (1984) 385] was used to calculate the oxygen isotope composition of meteoric waters. The mean air temperature was inferred from these isotope ratios and the Von Grafenstein et al.’s [Geochim. Cosmochim. Acta 60 (1996) 4025] relationship between δ18O and air temperature. Oxygen isotope composition of present-day individuals yields a mean air temperature of 9.9± 1.7 ∘C which is consistent with meteorological data. Application of this method to historical individuals results in mean air temperatures estimates 0 to 3 ∘C higher than present-day air temperature. These warm air temperatures are not realistic during the so-called Little Ice Age for which an air-cooling of about 0.5 to 2 ∘C has been documented. We propose that these relatively high δ18O values of human tooth enamel reflect higher mean δ18O values of meteoric water which can be attributed to an increased proportion of summer rainfall during the “Little Ice Age” time frame in Lorraine. 相似文献
14.
Abstract The abundance of magnetic microspherules in a Triassic-Jurassic continuous sequence of alternating chert and shale beds in the Mino accretionary complex, central Japan, was measured systematically. Depending on time, the magnetic microspherules extracted from shale beds change in abundance considerably from the minimum 0.9ppm/cm3 at latest Triassic ( ca 208Ma) and the maximum 75ppm/cm3 at late Early Jurassic ( ca 187Ma); however, the abundance is always higher approximately 10–100 (average 70) times than those from adjacent chert bed at any stratigraphic horizon. Such systematic difference reveals the origin of radiolarian bedded chert as cyclic-rapid accumulation of biogenic SiO2 under extremely slow accumulative environments of shale with probable aeolian dust in origin. The accumulation data for individual shale and chert beds were obtained based on the microspherule abundance and radiolarian biostratigraphy, i.e., ca 0.018g/cm2 Ka for lower Jurassic shale beds and ca 1.9g/cm2 Ka for adjacent chert beds.
Duration time to make a chert-shale couplet corresponds to a dominantly 15–20Ka interval (average 23 Ka) in Upper Triassic bedded cherts with a low paleolatitude, whereas a 40–45 Ka interval (average 42 Ka) in Lower Jurassic ones which may been formed in higher latitude than Triassics before the final accretion to the Asian continental margin. Depending on paleolatitude, the cyclicity of 23 and 42 Ka may correspond to Milankovitch cycles which have been well documented in deep-sea sediments. 相似文献
Duration time to make a chert-shale couplet corresponds to a dominantly 15–20Ka interval (average 23 Ka) in Upper Triassic bedded cherts with a low paleolatitude, whereas a 40–45 Ka interval (average 42 Ka) in Lower Jurassic ones which may been formed in higher latitude than Triassics before the final accretion to the Asian continental margin. Depending on paleolatitude, the cyclicity of 23 and 42 Ka may correspond to Milankovitch cycles which have been well documented in deep-sea sediments. 相似文献
15.
In seismic waveform inversion, non‐linearity and non‐uniqueness require appropriate strategies. We formulate four types of L2 normed misfit functionals for Laplace‐Fourier domain waveform inversion: i) subtraction of complex‐valued observed data from complex‐valued predicted data (the ‘conventional phase‐amplitude’ residual), ii) a ‘conventional phase‐only’ residual in which amplitude variations are normalized, iii) a ‘logarithmic phase‐amplitude’ residual and finally iv) a ‘logarithmic phase‐only’ residual in which the only imaginary part of the logarithmic residual is used. We evaluate these misfit functionals by using a wide‐angle field Ocean Bottom Seismograph (OBS) data set with a maximum offset of 55 km. The conventional phase‐amplitude approach is restricted in illumination and delineates only shallow velocity structures. In contrast, the other three misfit functionals retrieve detailed velocity structures with clear lithological boundaries down to the deeper part of the model. We also test the performance of additional phase‐amplitude inversions starting from the logarithmic phase‐only inversion result. The resulting velocity updates are prominent only in the high‐wavenumber components, sharpening the lithological boundaries. We argue that the discrepancies in the behaviours of the misfit functionals are primarily caused by the sensitivities of the model gradient to strong amplitude variations in the data. As the observed data amplitudes are dominated by the near‐offset traces, the conventional phase‐amplitude inversion primarily updates the shallow structures as a result. In contrast, the other three misfit functionals eliminate the strong dependence on amplitude variation naturally and enhance the depth of illumination. We further suggest that the phase‐only inversions are sufficient to obtain robust and reliable velocity structures and the amplitude information is of secondary importance in constraining subsurface velocity models. 相似文献
16.
PALEOCLIMATIC CHANGES DURING THE LAST 2.5Ma RECORDED IN THE KATHMANDU BASIN, CENTRAL NEPAL HIMALAYAS 相似文献