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811.
This study provides a procedure for assessing seismic hazardand uncertainties in regions that are characterised by a large non-instrumental earthquakedatabase and a seismic and tectonic behaviour which doesn't allow an evident seismic zonation.This procedure is a synthesis of the non-zoning or non-parametric methodology (using extremevalues distribution functions as proposed by Epstein and Lomnitz, 1966) and the zoning orparametric methodology (using the theorem of total probability as proposed by Cornell, 1968)via a logic tree procedure taking into consideration the advantages offered by each of these.Taking the area which we shall describe as the east coast of Spain and surrounding inland areas,an application was made and a specific logic tree was developed in order to solve the problems anduncertainties related to the evaluation of the seismic hazard using both methodologies. The use of thelogic tree allowed the systematisation of a large number of solutions obtained. A number of relevantresults were obtained which show that in some cases there are great differences in the seismichazard results provided by the non-zoning and the zoning methodologies. In these cases, mean value andstandard deviation of the obtained results provide an intermediate solution to the over-conservativeestimation provided by the non-zoning methodology and the lowest results provided by the zoningmethodology. In other cases results provided by both methodologies are significantly closer.In any case, synthesis among both methodologies gives a wider knowledge of the uncertaintiesassociated with the seismic hazard results. Finally uncertainties increase with the decreaseof the annual probability of exceedence and in sites with a seismic history of large size earthquakes. 相似文献
812.
813.
最大效果测度值法研究矿井突水水源 总被引:2,自引:0,他引:2
为了快速准确地查清矿井突水水源,排除水患对生产的影响,利用最大效果测度值燕子山矿14-2#煤层顶板砂岩裂隙水,其导水通道为工作面所在盘区发育的F23和F38正断层。最大效果测度值为矿井防治水工作提供了一个新的思路。 相似文献
814.
Abstract: In order to know the cause of the high δ34 S values of the Korean ore deposits (Ishihara et al., 2000), Geumseong molybdenum skarn deposit and related Jurassic granitoids and Cambro-Ordovician carbonates were selected for the δ34 S analyses. Two sulfide samples occurring in hydrothermal veins in fresh granitoids quarry at Songhaksan yielded δ34 S values of +6.9 and +8.8 permil. These are slightly higher than +5.3 permil δ34 S of the averaged rock sulfides for the Jurassic Daebo granitoids. Pyrite and molybdenite from the Geumseong deposit vary from +8.6 to +11.5 permil (average + 10.7 permil). The intruded carbonates contain very low amount of SSS (structurally substituted sulfate) as 2.9 to 8.1 ppm with high δ34 S values between +28.8 and + 40.0 permil, and sulfides sulfur of 52 to 779 ppm with variable δ34 S values between +3.2 and +22.5 per–mil. It is concluded that sulfur of the host carbonates was extracted and migrated into the skarn deposit at the time of the granitoid intrusion and the related hydrothermal convection, on the basis of the location of the skarn deposit occurring between the carbonates and Jurassic granitoids, and of very low contents of SSS sulfur in the carbonates. A part of SSS possibly contaminated into the Jurassic granite. 相似文献
815.
Undiscovered oil and gas assessments are commonly reported as aggregate estimates of hydrocarbon volumes. Potential commercial value and discovery costs are, however, determined by accumulation size, so engineers, economists, decision makers, and sometimes policy analysts are most interested in projected discovery sizes. The lognormal and Pareto distributions have been used to model exploration target sizes. This note contrasts the outcomes of applying these alternative distributions to the play level assessments of the U.S. Geological Survey's 1995 National Oil and Gas Assessment. Using the same numbers of undiscovered accumulations and the same minimum, medium, and maximum size estimates, substitution of the shifted truncated lognormal distribution for the shifted truncated Pareto distribution reduced assessed undiscovered oil by 16% and gas by 15%. Nearly all of the volume differences resulted because the lognormal had fewer larger fields relative to the Pareto. The lognormal also resulted in a smaller number of small fields relative to the Pareto. For the Permian Basin case study presented here, reserve addition costs were 20% higher with the lognormal size assumption. 相似文献
816.
817.
基于EGM96模型的GPS水准拟合方法 总被引:1,自引:0,他引:1
用GPS测量的方法来获得一点的正高或正常高,需要知识一点的大地水准面差距或高程异常。采用的大地水准面差距或高程异常的精度,决定了GPS水准的精度。本文利用EGM96模型计算高程异常。在利用巳知水准点上的高程异常拟合区域大地水准面模型时,首先移去用EGM96模型计算得到的部分,然后对剩余的高程异常进行拟合和内插,在内插点上再利用EGM96模型把移去的部分恢复,得到该点的高程异常。通过对某线路GPS水准的计算表明,引入EGM96模型拟合高程的精度改进不大。但对于大范围测量,这种方法有望能改进GPS水准的拟合精度。 相似文献
818.
Optimization of land use structure consists of economic and social and ecological optimization.Applying the minds of system engineering and principles of ecology,this paper presents such thoughts:the optimal forest-coverage rate calculated according to the reality of a district is set as main standard of ecological rationality in the district;through considering the value of ecosystem services of the land with GREEN equivalent(mainly cultivated land and grassland)and based on the rule GREEN equivalent,this paper introduces the area conversion between woodland and cultivated land ,also between woodland and grassland;this paper establishes a multi-dimension controlling model of optimization of land use structure,In addition,a multiobjective linear programming model for optimization of land use structure is designed.In the end,this paper tests and verifies this theory of ecological optimization,taking Qionghai city in Hainan Province as an example. 相似文献
819.
对溪洛渡水电站坝址温度场330m和360m高程平切温度等值线图中高温区展布形态和渗流场360m高程至下伏灰岩顶板平均吕荣(Lu)值等值线图中高值区展布形态进行了对比研究,认为二者在分布形态、延展方向及高温-高值点位置都极其相近,其原因是由该区特定的地热水文地质条件决定的;并认为在具有如溪洛渡坝址这样类似地热水文地质条件的地区,可以通过对地热温度场的研究,从另一侧面来论证同一区内岩层渗透性分布特性;利用温度场效应亦可对渗流场参数进行验证研究,以用于水利水电工程设计。 相似文献
820.
恢复额济纳旗生态系统的总经济价值——条件估值非参数估计方法的应用 总被引:10,自引:4,他引:10
条件估值方法是当前国际上流行的衡量环境物品非利用经济价值的方法, 通过调查居民针对不同环境状况变化的支付意愿,从而定量确定环境状况变化带来的经济效益和损失. 针对黑河流域额济纳旗生态系统恶化的现状,以投标支付卡的方法设计了700份调查问卷,调查了黑河流域居民恢复额济纳旗生态系统的支付意愿,并采用非参数分析方法对结果进行分析. 结果表明,用20 a的时间将额济纳旗的生态系统恢复到20世纪80年代初的水平,黑河流域总共有92.3%的居民家庭存在支付意愿,有支付意愿家庭的平均支付意愿为每年每户43.39元,同时采用列联表检验的方法辨明了被调查者的年龄、学历、收入、户籍和居住的地理区域等因素对支付意愿的影响. 最后在综合不同区域居民支付意愿差异的基础上,采用当前的市场利率将计算结果在时空尺度上加总,得到恢复黑河下游额济纳生态系统的总经济价值的现值为2.94×10+8元. 相似文献