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1.
通过评估GPM计划三种日降水产品（IMERG-E、 IMERG-L和IMERG-F）和TRMM卫星、 两种日降水产品（TMPA 3B42和TMPA 3B42RT）在黄河源及其周边区域38个台站的适用性, 探究了五种产品探测精度和海拔高度及雨强的相关关系, 结果表明： 在与实测资料的一致性和偏差方面, GPM卫星产品要全面优于TMPA产品。在TRMM卫星产品中, 3B42产品明显优于3B42RT。五种产品的相关系数均表现出明显的从东南到西北递减的趋势, 均方根误差北部普遍低于南部。IMERG产品的探测率（POD）和探测成功率（CSI）都要普遍高于TMPA产品, 而误报率（FAR）则是TMPA 产品更低, 表现更好。五种产品均在个别台站出现了严重误报的情况, 这些台站主要分布在研究区的西北部。IMERG三种产品对于海拔高度的依赖程度具有很强的一致性, 而3B42RT产品对海拔高度几乎没有依赖。除3B42RT产品外, 其余四种产品的偏差均随雨强的增加而增大。在探测率方面, IMERG产品对小雨、 中雨和大雨的探测能力均优于TMPA产品。 相似文献
2.
In this paper, an artificial neural network (ANN)?Cbased methodology is proposed to determine the probability of inter-arrival time (IAT) of main shock of six broad seismic regions of India. Initially, classical methodology using exponential distribution is applied to IAT of earthquake events computed from earthquake catalog data. From the goodness-of-fit test results, it has been found that exponential distribution is not adequate. In this paper, a more efficient ANN-based methodology is proposed, and two ANN models are developed to determine the probability of IAT of earthquake events for a specified region, specified magnitude range or magnitude greater than the specified value. The performance of ANN models developed is validated with number of examples and found to predict the probability with minimal error compared to exponential distribution model. The methodology developed can be applied to any other region with the database of the respective regions. 相似文献
3.
《地学前缘(英文版)》2016,7(1)
A new model is derived to predict the peak ground acceleration(PGA) utilizing a hybrid method coupling artificial neural network(ANN) and simulated annealing(SA), called SA-ANN. The proposed model relates PGA to earthquake source to site distance, earthquake magnitude, average shear-wave velocity,faulting mechanisms, and focal depth. A database of strong ground-motion recordings of 36 earthquakes,which happened in Iran's tectonic regions, is used to establish the model. For more validity verification,the SA-ANN model is employed to predict the PGA of a part of the database beyond the training data domain. The proposed SA-ANN model is compared with the simple ANN in addition to 10 well-known models proposed in the literature. The proposed model performance is superior to the single ANN and other existing attenuation models. The SA-ANN model is highly correlated to the actual records(R=0.835 and r =0.0908) and it is subsequently converted into a tractable design equation. 相似文献
4.
Metropolitan areas consist of complicated systems of interconnected infrastructures that are highly interdependent. Disruption of one infrastructure may induce disruption in other interconnected ones. The results from analysis of one infrastructure as an independent system are not realistic without considering the behavior of other interconnected infrastructures. Consequently, the study of the interdependencies among critical infrastructures is important for addressing the cascading effects of a failed infrastructure on the entire network to properly model its performance and help the disaster management team in decision making. In this study, the extended Petri net and Markov chain have been used to demonstrate the power and water infrastructure interdependency with a case study of one of the municipal districts of metropolitan Tehran, the capital of Iran. In this research, three cases have been assessed quantitatively: (1) the intra-dependency effects of different components in each network, (2) the interdependency effects between the considered critical infrastructures and (3) the behavior of the water network considering intra- and interdependency, when the power network fails. The analyses show that considering the mentioned interdependencies has a major influence on their performance simulations and assessment of their exact vulnerability. It is concluded that the failure probability of the water network that is dependent on the failed power network is 1.66 of the independent water network in the studied region. Eventually, the results of the research could be used in design, restoration and disaster management planning for safety assessment of critical infrastructures. 相似文献
5.
The paper proposes a new empirical model to estimate earthquake ground-motion duration, which significantly influences the damage potential of an earthquake. The paper is concerned with significant duration parameters that are defined as the time intervals between which specified values of Arias intensity are reached. In the proposed model, significant duration parameters have been expressed as a function of moment magnitude, closest site-source distance, and site condition. The predictive model has been developed based on a database of earthquake ground-motion records in Iran, containing 286 records up to the year 2007, and a random-effect regression procedure. The result of the proposed model has been compared with that of other published models. It has been found that the proposed model can predict earthquake ground-motion duration in Iran with adequate accuracy. 相似文献
6.
Sokolov Vladimir Ovcharenko Arkady Loh Chin-Hsiung Wen Kuo-Liang 《Natural Hazards》2004,33(3):319-363
The paper describes an integrated approach to seismic hazard assessment, which was applied for the Taiwan region. First, empirical modelsfor ground motion estimation in the region were obtained on the basisof records from recent (1993-1999) earthquakes. The databaseincludes strong-motion data collected during the recent Chi-Chiearthquake (M=7.6, 21 September 1999) and large (M=6.8)aftershocks. The ground-motion database was also used for evaluationof generalised site amplification functions for typical soil classes(B, C and D). Second, the theoretical seismic catalogue (2001–2050)for the Taiwan region had been calculated using the 4D-model(location, depth, time) for dynamic deformation of the Earth' crustand 5D-model (location, depth, time, magnitude) for seismic process.The models were developed on the basis of available geophysical andgeodynamic data that include regional seismic catalogue. Third, theregion & site & time-dependent seismic analysis, which is basedon schemes of probable earthquake zones evaluated from the theoreticalcatalogue, regional ground motion models, and local site responsecharacteristics, has been performed. The seismic hazard maps arecompiled in terms of Peak Ground Acceleration (PGA) and ResponseSpectra (RS) amplitudes. The maps show distribution of amplitudesthat will not be exceeded with certain probability in condition oftypical soil classes during all possible earthquakes that may occur inthe region during time period of 2003–2025. The approach allowsintroducing new parameter that describes dependency of seismichazard on time, so-called 'period of maximum hazard'. Theparameter shows the period, during which every considered sitewill be subjected by the maximum value of ground motioncharacteristic (PGA or RS). 相似文献
7.
《Computers and Geotechnics》2006,33(4-5):260-274
Three-dimensional (3D) evaluation of slope stability is a widely addressed problem in the domain of geotechnical engineering. The growing popularity of the geographical information system (GIS) approach, with capacities ranging from conventional data storage to complex spatial analysis and graphical presentation, means that it is also becoming a powerful tool for geotechnical engineers. In this study, in which we combine GIS grid-based data with four proposed column-based models of 3D slope stability analysis, we have devised new correspondent GIS grid-based 3D deterministic models to calculate the safety factor of the slope. Based on the four GIS-based 3D slope stability analysis models, a GIS-based program, 3DSlopeGIS, has been developed to implement the algorithm where all the input data are in the same format as the GIS dataset. The 3DSlopeGIS system, which is an extension of the widely used GIS software package, represents the combined development of 3D slope stability analysis and GIS-based component object model (COM) skills. Since all related data are supplied in the GIS format, this new database approach will be convenient for the repeated renewal and consulting of data. Certain widely addressed examples are evaluated in this paper and the results show the correction and potential of this GIS-based tool as a means of assessing the 3D stability of a slope. Two practical slope problems have been evaluated using the 3DSlopeGIS system. The results illustrate the convenience of data management as well as the effective range selection of Monte-Carlo random variables and the critical slip surface location in some parts of a lava dome. 相似文献
8.
The ensemble Kalman filter has been successfully applied for data assimilation in very large models, including those in reservoir
simulation and weather. Two problems become critical in a standard implementation of the ensemble Kalman filter, however,
when the ensemble size is small. The first is that the ensemble approximation to cross-covariances of model and state variables
to data can indicate the presence of correlations that are not real. These spurious correlations give rise to model or state
variable updates in regions that should not be updated. The second problem is that the number of degrees of freedom in the
ensemble is only as large as the size of the ensemble, so the assimilation of large amounts of precise, independent data is
impossible. Localization of the Kalman gain is almost universal in the weather community, but applications of localization
for the ensemble Kalman filter in porous media flow have been somewhat rare. It has been shown, however, that localization
of updates to regions of non-zero sensitivity or regions of non-zero cross-covariance improves the performance of the EnKF
when the ensemble size is small. Localization is necessary for assimilation of large amounts of independent data. The problem
is to define appropriate localization functions for different types of data and different types of variables. We show that
the knowledge of sensitivity alone is not sufficient for determination of the region of localization. The region depends also
on the prior covariance for model variables and on the past history of data assimilation. Although the goal is to choose localization
functions that are large enough to include the true region of non-zero cross-covariance, for EnKF applications, the choice
of localization function needs to balance the harm done by spurious covariance resulting from small ensembles and the harm
done by excluding real correlations. In this paper, we focus on the distance-based localization and provide insights for choosing
suitable localization functions for data assimilation in multiphase flow problems. In practice, we conclude that it is reasonable
to choose localization functions based on well patterns, that localization function should be larger than regions of non-zero
sensitivity and should extend beyond a single well pattern. 相似文献
9.
Probabilistic seismic hazard maps for the sultanate of Oman 总被引：2，自引：0，他引：2
I. El-Hussain A. Deif K. Al-Jabri N. Toksoz S. El-Hady S. Al-Hashmi K. Al-Toubi Y. Al-Shijbi M. Al-Saifi S. Kuleli 《Natural Hazards》2012,64(1):173-210
This study presents the results of the first probabilistic seismic hazard assessment (PSHA) in the framework of logic tree for Oman. The earthquake catalogue was homogenized, declustered, and used to define seismotectonic source model that characterizes the seismicity of Oman. Two seismic source models were used in the current study; the first consists of 26 seismic source zones, while the second is expressing the alternative view that seismicity is uniform along the entire Makran and Zagros zones. The recurrence parameters for all the seismogenic zones were determined using the doubly bounded exponential distribution except the zones of Makran, which were modelled using the characteristic distribution. Maximum earthquakes were determined and the horizontal ground accelerations in terms of geometric mean were calculated using ground-motion prediction relationships developed based upon seismic data obtained from active tectonic environments similar to those surrounding Oman. The alternative seismotectonic source models, maximum magnitude, and ground-motion prediction relationships were weighted and used to account for the epistemic uncertainty. Hazard maps at rock sites were produced for 5?% damped spectral acceleration (SA) values at 0.1, 0.2, 0.3, 1.0 and 2.0?s spectral periods as well as peak ground acceleration (PGA) for return periods of 475 and 2,475?years. The highest hazard is found in Khasab City with maximum SA at 0.2?s spectral period reaching 243 and 397?cm/s2 for return periods 475 and 2,475 years, respectively. The sensitivity analysis reveals that the choice of seismic source model and the ground-motion prediction equation influences the results most. 相似文献
10.
A major assumption of the Empirical Transport Model (ETM), widely adopted by both electric utilities and regulatory agencies
for estimating the effects of entrainment mortality on fish populations in estuaries, is that the fraction of ichthyoplankton
entrained varies only in response to changes in water withdrawals, not to changes in freshwater flow. We evaluated this assumption
using a particle-tracking model to estimmate the probability of entrainment at power plants on the Hudson River during low
and high freshwater flow periods and comparing those probabilities with estimates calculated from the ETM. We found that freshwater
flow had a profound effect on the probability of entrainment. Both the number of river regions from which particles were entrained
and the probabilities of entrainment for particles in those river regions differed between low-flow and high-flow periods.
During high flow, particles spent less time in the grid box next to the intakes, reducing the probability of entrainment for
particles released in the river region of each power plant and the average probability of entrainment across all regions at
three power plants. The reduced probability of entrainment for particles released in the river regions of two power plants
was offset by higher entrainment for particles upriver of these power plants. Although the average probabilities of entrainment
across all river regions estimated with the particle-tracking model and the ETM were relatively similar for some power plants
at high flow, low flow, or both, the probabilities for each river region differed considerably between the models. The number
of river regions from which particles were entrained using the ETM was consistently undersestimated, resulting in probabilities
for regions where entrainment occurred that were biased high compared with the particle-tracking model. 相似文献
11.
Probabilistic seismic hazard analysis for Sumatra, Indonesia and across the Southern Malaysian Peninsula 总被引：1，自引：0，他引：1
Mark D. Petersen James Dewey Stephan Hartzell Charles Mueller Stephan Harmsen ArthurD. Frankel Ken Rukstales 《Tectonophysics》2004,390(1-4):141-158
The ground motion hazard for Sumatra and the Malaysian peninsula is calculated in a probabilistic framework, using procedures developed for the US National Seismic Hazard Maps. We constructed regional earthquake source models and used standard published and modified attenuation equations to calculate peak ground acceleration at 2% and 10% probability of exceedance in 50 years for rock site conditions. We developed or modified earthquake catalogs and declustered these catalogs to include only independent earthquakes. The resulting catalogs were used to define four source zones that characterize earthquakes in four tectonic environments: subduction zone interface earthquakes, subduction zone deep intraslab earthquakes, strike-slip transform earthquakes, and intraplate earthquakes. The recurrence rates and sizes of historical earthquakes on known faults and across zones were also determined from this modified catalog. In addition to the source zones, our seismic source model considers two major faults that are known historically to generate large earthquakes: the Sumatran subduction zone and the Sumatran transform fault. Several published studies were used to describe earthquakes along these faults during historical and pre-historical time, as well as to identify segmentation models of faults. Peak horizontal ground accelerations were calculated using ground motion prediction relations that were developed from seismic data obtained from the crustal interplate environment, crustal intraplate environment, along the subduction zone interface, and from deep intraslab earthquakes. Most of these relations, however, have not been developed for large distances that are needed for calculating the hazard across the Malaysian peninsula, and none were developed for earthquake ground motions generated in an interplate tectonic environment that are propagated into an intraplate tectonic environment. For the interplate and intraplate crustal earthquakes, we have applied ground-motion prediction relations that are consistent with California (interplate) and India (intraplate) strong motion data that we collected for distances beyond 200 km. For the subduction zone equations, we recognized that the published relationships at large distances were not consistent with global earthquake data that we collected and modified the relations to be compatible with the global subduction zone ground motions. In this analysis, we have used alternative source and attenuation models and weighted them to account for our uncertainty in which model is most appropriate for Sumatra or for the Malaysian peninsula. The resulting peak horizontal ground accelerations for 2% probability of exceedance in 50 years range from over 100% g to about 10% g across Sumatra and generally less than 20% g across most of the Malaysian peninsula. The ground motions at 10% probability of exceedance in 50 years are typically about 60% of the ground motions derived for a hazard level at 2% probability of exceedance in 50 years. The largest contributors to hazard are from the Sumatran faults. 相似文献
12.
Natural Hazards - Earthquake ground-motion prediction equations for soil and rock sites in northern Iran have been developed based on stochastic models and Bayesian updating. Due to a lack of... 相似文献
13.
Models of spatial choice behaviour have been around in geography urban planning for decades to assess the feasibility of planning
actions or to predict external (competition) effects on existing destinations. Although these models differ in terms of complexity
and key concepts, they all have in common that spatial choice behaviour is predicted as a function of the attributes of the
choice alternatives and distance or travel time separation only. None of these models do take into account that the attributes
of choice alternatives and travel time may be highly non-stationary and that often the utility that people derive from visiting
a particular location also depends on the choice behaviour of other individuals. Under these circumstances, individuals may
exhibit strategic choice behaviour. That is, they will choose particular choice options taking into account their expected
behaviour of others such as to maximize their own utility. The purpose of the proposed paper is to discuss possible models
of strategic choice behaviour for these urban planning problems. Theory will be outlined and some critical issues in the application
of such models to problems of spatial choice will be discussed. 相似文献
14.
基于不同类型金矿床的能谱测据与金品位之间有不同的相关关系,对具体矿床单独建模预测是必要和可能的。能谱找金测据处理系统的设计就是根据测据处理的数学方法和步骤编制的。常用的多元线性回归分析预测效果往往不理想,而本系统对能谱测据作适当变换并计算权值、差值和有利度等预处理后,回归准确性显著提高。它同时可建立十多个数学模型,使用户有较大的选择余地。它采用树状程序结构,全中文菜单式提示,可逐级调用,也可单独运行各级子系统。它可移植于其它类似的地质矿床模型的测据(包括非能谱测据)处理。该系统快速、准确、简便、灵活,具有较大的实用性和推广价值。 相似文献
15.
It has been suggested that regional array MTS data be processed with an algorithm based on the nonlocal response of laterally heterogeneous subsurface to an arbitrary electromagnetic excitation. The algorithm is tested with synthetic models which show that the inversion quality can be improved by accumulation of information through repeated measurements, at either changing or fixed array configurations. Besides the array configuration, the inversion quality depends on the selected size of the survey area. The choice of the area size defines the inversion conditions in terms of choice between the magnetic and electric mode for correlation of electromagnetic potentials. The algorithm has been applied to data acquired during the BEAR Project in the Fennoscandian shield. Preliminary results indicate a spatial correlation between conductivity minimums and Moho depth maximums. The apparent resistivity maps obtained with the suggested algorithm highlight the boundaries between the Lapland–Kola, Karelia, and Svecofennia tectonic provinces. 相似文献
16.
Investigation into MOGA for identifying parameters of a critical-state-based sand model and parameters correlation by factor analysis 总被引：1，自引：1，他引：0
Adding refinement and accuracy to constitutive models of soil results in the introduction of complexities along with more model parameters. These parameters (such as hardening-/softening-, dilatancy-/contractancy-related parameters and critical state parameters) are usually not easily obtained in a straightforward way. How to identify these key parameters and estimate their correlations of advanced soil models is a particular issue for geotechnical engineering. This paper was aimed to investigate multi-objective genetic algorithms for identifying parameters of advanced sand models based on standard laboratory tests, followed by the correlation analysis of parameters. A critical-state-based sand model has been developed to simulate three triaxial compression tests performed on loose and dense Hostun sand. Two widely used genetic algorithms with two initialisation methods are examined. The performance of the two genetic algorithms is assessed by comparing their simulation performance using optimal parameters, the convergence speed and the distribution of solutions on the Pareto front. The optimal parameters can then be classified into two factors by their correlation relationship. 相似文献
17.
A soil deposit subjected to seismic loading can be viewed as a binary system: it will either liquefy or not liquefy. Generalized linear models are versatile tools for predicting the response of a binary system and hence potentially applicable to liquefaction prediction. In this study, the applicability of four generalized linear models (i.e., logistic, probit, log–log, and c-log–log) for liquefaction potential evaluation is assessed and compared. Eight liquefaction models based on the four generalized linear models and two sets of explanatory variables are evaluated. These models are first calibrated with past liquefaction performance data. A weighted-likelihood function method is used to consider the sampling bias in the calibration database. The predicted liquefaction probabilities from various models are then compared. When liquefaction probability is small, the predicted liquefaction probability is sensitive to the regression models used. The effect of sampling bias is more marked in the high cyclic stress ratio region. The eight models are finally ranked using a Bayesian model comparison method. For the generalized linear models examined, the logistic and c-log–log regression models are most supported by the past performance data. On the other hand, the probit and c-log–log regression models are much less applicable to liquefaction prediction. 相似文献
18.
Edison Dayal Dr. 《GeoJournal》1985,11(4):369-382
The main objectives of this paper are to identify and account for the regional variations in the rural household incomes and inequalities in income distribution between and within regions in India. Clearly, higher average incomes are concentrated in the W and NW regions, and very low incomes in the densely populated E and S. These differences have been analysed through the use of correlation and regression model, based on 15 variables. The results indicate that agricultural development (reflected in mechanization and irrigation), size of holdings, and family size have a positive influence on incomes, and landlessness negative. Further, a significant negative correlation between low caste population density and household incomes suggests that, at least, some of the impoverishment in the villages may be attributed to an unfair social structure that has developed and has been maintained over a long time in India. This conclusion is further reinforced by comparing income data from regions dominated by tribal social system and community ownership of land with those where Hindu caste system and private ownership of land are dominant. 相似文献
19.
Determining fault activity through time has typically utilised high-resolution seismic data to identify stratigraphic thickness changes or displacement vs distance plots; however, this approach is not possible in regions with low-resolution seismic data. We present a new approach for determining fault reactivation (tensile and shear) through time by integrating three-dimensional seismic data, geomechanical modelling and complete paleostress tensors from calcite twin stress inversion. The Cooper–Eromanga Basin is used as a case study to model the stress conditions present during six tectonic events that have affected the basin and, in doing so, constrain the effective paleostress magnitudes through time. Results show that the likelihood of dilation and shear reactivation of individual fault sets varies through time, with N–S- and E–W-striking faults likely to have been open to fluid flow after the critical moment in the hydrocarbon system. These results have substantial implications for hydrocarbon migration pathway models and structural and stratigraphic models for the Cooper–Eromanga Basin. This approach would benefit other provinces with low-resolution seismic data preventing fault growth analysis, or in regions where hydrocarbon migration pathways are poorly defined. 相似文献
20.
锚杆挡土墙可靠度分析与计算方法 总被引：1，自引：0，他引：1
提出了锚杆挡墙中肋柱锚杆体系的串-并联模型。将肋柱视为连续梁,锚杆视为弹性支座,引入锚杆与锚固段周围岩土体的复合刚度系数,用位移法导出了各根锚杆所受荷载的统一计算公式。考虑各功能函数之间的相关性,运用系统可靠性理论,提出了单根锚杆3种破坏模式的串联系统与多根锚杆并联系统的体系可靠度计算方法,并编制了计算程序。对一工程实例进行计算,并对计算结果进行了分析,发现单根锚杆的3种失效模式并非相互独立,每种失效模式对锚杆可靠度的影响也不一样,而3根锚杆并联系统的失效概率近似等于在其他锚杆均未破坏的条件下每根锚杆单独失效概率之和。 相似文献