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1.
我国地震海啸危险性分析方法研究   总被引:4,自引:0,他引:4  
美国、日本等国家已经建立了完善的海啸防灾减灾机制,对海啸危险性分析方法的研究也做了很多的工作,而我国目前在这方面尚属空白。本文首次对我国的海啸危险性分析方法进行了研究,提出了我国地震海啸危险性分析的基本原则,在此基础上,借鉴我国成熟的地震危险性分析方法,建立了我国地震海啸危险性分析方法的主要步骤。在根据我国一些历史地震海啸资料的基础上,通过统计的方法对我国珠江三角洲的海啸危险性进行了研究。  相似文献   

2.
带相位信息的一维大地电磁曲线对比反演法   总被引:3,自引:0,他引:3       下载免费PDF全文
张大海  徐世浙 《地震地质》2001,23(2):227-231
在大地电磁连续介质曲线对比法反演的基础上,引入了相位信息,即在反演的模型视电阻率的修改量中加入了相位改正量,从而提高了收敛速度,稳定了反演过程。与其他方法的模型研究比较,加入相位信息的曲线对比法反演的结果,能够较真实地反映模型的电性分布,并可为多维反演提供初始模型。  相似文献   

3.
单项资料异常变化信息提取的一种新方法:多点组信息法   总被引:1,自引:0,他引:1  
在前人工作的基础上提出了多点组信息法,包容了以前各种各样的数据处理方法,并赋予了新的内容,以4点组斜率信息法为例,做了系统的论述,并以小水峪垂直基线资料为例,给出了初步的处理结果,证明该方法在各种数据的分析处理、提取地震前兆异常信息的应用中有较大的价值,最后给出了标准化信息流,对多项不同量纲的异常信息合成提供了方便。  相似文献   

4.
在地震勘探中,近地表的不均匀性给激发、接收和静校正等带来很大的困难.WX地区浅表层分布有多期火成岩,对地震勘探造成很大的影响,本文实际工作从发分析了各种地震表层结构调查方法,并对小折射、井中激发地表接收微测井和地表激发井中接收的微测井等常用方法,进行了同点对比试验.选择了最合适的表层结构调查方法,辅以钻井岩性描述,建立了工区的详细准确的表层岩性变化模型,指导地震野外采集方法设计,并求取模型静校正量.取得了较好的地震资料.  相似文献   

5.
测井曲线Milankovitch周期分析与应用   总被引:12,自引:0,他引:12       下载免费PDF全文
利用沿井剖面滑动时窗内的FFT和最大熵谱估计算法,选择合适的滤波器、窗长和步长,从测井曲线中分析出了Milankovitch周期.研究了波长比,谱峰等特征与周期的关系,确定出沉积速率的渐变与突变,求出了沉积速率,经分析,与岩性结果相符合.  相似文献   

6.
本文从地球物理场出发,通过严密的数学物理推导,提出了磁力测深公式,并导出了著名的重力测深公式的更一般表达式。为了得到更为精确的解,本文又提出了应用最优化理论的空间域迭代算法,并根据地球物理模型对于高斯优化法进行了改进,在算法上有所创新,使其在计算机上实现时算法简单,计算速度快。文中还列举了一些模型的实验结果,对磁力测深公式及迭代算法的有效性及可靠性进行了论证。用本文方法对实际资料的处理结果是令人满意的,证明该方法有一定的实用性。  相似文献   

7.
云南深部热流研究   总被引:6,自引:0,他引:6       下载免费PDF全文
阐述了云南大地热流分布特征,并从地壳结构入手探讨了地壳、上地幔的生热率垂向分布,进而研究了云南的深部热流结构.研究结果表明,垂向上,上地壳所产生的热流量最大,中地壳次之,下地壳最小;横向上,各构造单元深部热流结构差别较大,全区地幔热流变化范围是19~57mW/m2.  相似文献   

8.
近地表高频补偿技术在三维地震勘探中的应用研究   总被引:7,自引:1,他引:7  
近地表的滤波作用不仅会引起地震波高频成分的快速衰减,还会引起地震子波相位的畸变,在高分辨率地震资料处理中,必须对这些由近地表引起的衰减和频散进行补偿.文中研究了近地表吸收规律,应用微测井资料求出了表层的吸收衰减因子,补偿了近地表高频成分,给出了针对三维地震资料的近地表高频补偿方法,对大庆齐家北工区的地震资料进行了实际应用,同时还应用属性分析技术对应用效果进行了分析评价,结果表明,该方法是可行的.  相似文献   

9.
基于位移的概率极限状态设计   总被引:1,自引:0,他引:1  
尽管近年来国内外学者提出了多种基于位移的抗震设计方法,但采用的与位移相关的反应谱大多是平均谱,设计过程可以看作是确定性的。基于位移的抗震设计应该建立在可靠度理论基础之上。利用作者在概率延性需求谱方面已有的研究成果和可靠度分析方法——验算点法,本文提出了根据基于位移的目标可靠指标直接进行结构设计的方法,并给出了设计流程图。为便于工程应用,在进行了大量分析计算之后,本文建议了基于位移的概率极限状态分项系数设计表达式,并确定了其中的分项系数。最后,本文对一8层框架结构采用建议的分项系数设计表达式进行了设计,并对有待于进一步研究的问题进行了简要分析。  相似文献   

10.
基于逆重复m序列的精细探测电法发送机设计   总被引:3,自引:3,他引:3       下载免费PDF全文
介绍了基于伪随机相关辨识理论的电法发送机设计思想.通过分析逆重复m序列伪随机信号的性质,产生原理,以及伪随机信号系统辨识的原理,研究了其在电法勘探应用中的可行性.用工程软件MATLAB仿真产生了逆重复m信号的波形,并分析了频谱和自相关函数,对产生伪随机信号的序列长度和时钟频率等参数的选择作出讨论,以说明其作为电法勘探场源的优良特点.作出了电法发送机系统初步设计,包括主控单元、逆变器、GPS同步,电流测量等模块,发送机信号控制单元采用硬件描述语言VHDL设计,并用CPLD可编程逻辑器件LC4256V实现了硬件产生m序列和逆重复m序列,及各种控制信号.宽频带、密频比,抗干扰能力强是其主要特点,在电法勘探中有良好的应用前景.  相似文献   

11.
Cores taken from 16 stations within Eight Day Swamp, a highly contaminated marsh in the Hackensack Meadowlands, were analyzed for metal concentrations and for benthic community structure. Metal levels were compared with the benchmark ERM values, and expressed in terms of toxic units. Mercury was the most important metal in all the samples in terms of its contribution to the total toxic units. The overall abundance and taxa richness in the benthic community were associated with the height of the location relative to the tidal cycle, but were generally not significantly correlated with metal concentrations at the sites. Ordination of the communities showed that the communities that were low-lying (on the mudflat) were most similar to one another, and those that were higher up on the marsh were most similar to one another. However, diversity indices (Shannon-Wiener H' and Simpson's) were significantly associated with concentrations of the metals (except As) and with the sum of the toxic units at a station.  相似文献   

12.
Sea turtles migrate to various habitats where they can be exposed to different pollutants. Bacteria were collected from turtle eggs and their resistance to antibiotics was used as pollutant bio-indicators of contaminated effluents. Eggs were collected randomly from turtles when they were laying their eggs. A total of 90 eggs were collected and placed into sterile plastic bags (3 eggs/turtle) during June-December of 2003. The bacteria located in the eggshell, albumen and yolk were examined, and 42% of the eggs were contaminated with 10 genera of bacteria. Pseudomonas spp. were the most frequent isolates. The albumen was found to be the part of the egg to be the least contaminated by bacterial infection. Bacterial isolates tested with 14 antibiotics showed variations in resistance. Resistance to ampicillin was the highest. The presence of antibiotic resistant bacteria in eggs indicates that the green turtle populations were subjected to polluted effluents during some of their migratory routes and feeding habitats. Scanning electron microscopy revealed that Salmonella typhimurium penetrated all eggshell layers.  相似文献   

13.
本文给出了一种改进的模态pushover方法,对竖向不规则结构进行抗震性能评估。通过考虑不规则结构高振型的影响,利用模态pushover方法将结构简化为不同的等效单自由度体系,并对其进行弹塑性时程分析,将所得到的结果进行组合,得到原结构的楼层位移和层间位移等性能指标。由于结构处于屈服阶段与处于弹性阶段时的各节点变形的关系有显著区别,因此对于进入塑性阶段的振型,采用屈服后的各节点变形关系计算位移变形响应,将计算得到的各个振型结果组合得到整体结构的位移。通过四个算例分析,表明改进的方法所得到的结果更加接近于弹塑性时程分析的结果,证明此方法能够有效地应用于竖向不规则结构的抗震性能评估与计算。  相似文献   

14.
Eight marine-derived fungi that were previously selected for their abilities to decolorize RBBR dye were subjected to pyrene and benzo[a]pyrene degradation. The fungus Aspergillus sclerotiorum CBMAI 849 showed the best performance with regard to pyrene (99.7%) and benzo[a]pyrene (76.6%) depletion after 8 and 16 days, respectively. Substantial amounts of benzo[a]pyrene (>50.0%) depletion were also achieved by Mucor racemosus CBMAI 847. Therefore, these two fungal strains were subjected to metabolism evaluation using the HPLC-DAD-MS technique. The results showed that A. sclerotiorum CBMAI 849 and M. racemosus CBMAI 847 were able to metabolize pyrene to the corresponding pyrenylsulfate and were able to metabolize benzo[a]pyrene to benzo[a]pyrenylsulfate, suggesting that the mechanism of hydroxylation is mediated by a cytochrome P-450 monooxygenase, followed by conjugation with sulfate ions. Because these fungi were adapted to the marine environment, the strains that were used in the present study are considered to be attractive targets for the bioremediation of saline environments, such as ocean and marine sediments that are contaminated by PAHs.  相似文献   

15.
Locational risks for compromised ecosystem health for the eastern oysters (Crassostrea virginica) harvested from Lavaca Bay, Texas were estimated. Flow cytometric evaluation of variations in DNA content and the lysosomal destabilization assay were used for evaluation of genotoxicity and stress, respectively. Bayesian geo-statistical methods were utilized to estimate and evaluate spatial effects. For models with spatial risks, continuous surface maps of predicted parameter values were created to evaluate risk location. Lysosomal destabilization assay results were spatially oriented whereas flow cytometry results were fit best with the random effects model. While not spatially oriented, the highest levels of variations in DNA content were also present near industrial facilities. Locational risks of increased biomarkers of genotoxicity and stress in the eastern oyster (Crassostrea virginica) were increased with proximity to industrial facilities  相似文献   

16.
2021年2月13日23点07分(当地时间)日本福岛县海域发生了7.3级地震,这是2011年以来东日本大地震记录到的较大余震。距离震源较近的强震动观测点记录到约1.5 g的最大加速度。对离震源较近的几个城市及乡村,包括郡山市、福岛市和仙台市以内的地方进行了建筑物的震害调查。调查中发现:日本常用的木结构民宅在地震中仅发生了屋顶的瓦片掉落和剥离等轻微破坏,并没有发生严重的破坏。另外,在郡山市和福岛市有几栋高层钢筋混凝土结构的房屋有较严重的损坏。2021年福岛地震这一现象可能与地震动的短周期特性(小于1s)以及建筑物的高次振型有关。  相似文献   

17.
利用框架结构的整体振动模态信息进行局部损伤的判别具有明显的局限性。高阶模态逐渐被人们认识并用来进行局部物理参数识别并用来进行损伤判别。本文以弹性地基上独立基础的框架结构底层柱为研究对象,利用增加的质量块对柱子进行局部损伤的制造,利用脉冲锤击法和激振器扫频实验进行高阶模态对比测试,利用PolyMAX模态分析方法进行损伤前后高阶模态的识别,发现了“高灵敏度高阶模态”的存在。最后通过两端约束Euler梁的计算模型,通过高阶模态来识别物理参数以及地基参数,其中物理参数结果具有较好的可靠性。  相似文献   

18.
In this paper, size‐exclusion chromatography (SEC) was used to determine the metal concentration in different size fractions of a bog lake water. Two methods were applied: (a) preparative SEC with off‐line metal concentration analysis and (b) direct coupling of an analytical SEC system on‐line with an inductively‐coupled plasma mass spectrometer (ICP‐MS). In the preparative SEC measurements, maximum concentrations were found for different metal ions in different size fractions of the natural organic matter (NOM). Normalization of metal concentrations to dissolved organic carbon concentration (DOC) yielded two maxima in the high and in the very low molecular‐weight fractions. Whereas good recoveries were found for Al, Fe, and Ni, only 40% were obtained for Pb. This indicates that Pb formed labile complexes with NOM, and hence could strongly interact with the column material. In the experiments with the analytical SEC‐ICP‐MS system, the same trends were observed, but with even lower recoveries than in the preparative system. Sample preconcentration and storage were also investigated with respect to decrease in metal concentration. During the ultrafiltration preconcentration step Al and Fe were removed only to a small extent, whereas about half of the initial Pb was lost. This indicates that Al and Fe were mainly bound to high molecular‐weight fractions of NOM. In contrast to that, Al and in particular Fe were removed from solution more than proportionally with respect to DOC because of aggregation of the NOM during storage, whereas Pb and Ni were concentrated relative to the DOC.  相似文献   

19.
Metals in Sediments of the Upper Laguna Madre   总被引:2,自引:0,他引:2  
The Laguna Madre system is the largest hypersaline coastal basin in the United States. Surface sediments from 22 Upper Laguna Madre (ULM) sites were analyzed for grain size and metals (Cd, Cu, Ba, Cr, Mn, Ni, Pb, V, Zn, Fe, and Al) to assess the extent of contamination in the area. Sediments were found to consist mainly of sand texture. Clay and silts were minor constituents (<10%) of the sediments. Anomalies in metal concentrations were found at some sites and were related to probable sources, i.e., recreational and industrial activities. Concentrations of metals were normalized to grain size, Al, and Fe to distinguish natural and anthropogenic sources. Most metals showed positive correlations (p < 0.001) with Fe and Al, suggesting a natural variability of metal concentrations in sediments. Concentrations of metals, except Cd and Pb, at most sites were found to be below threshold concentrations thought to produce toxic effects in marine and estuarine organisms.  相似文献   

20.
The county town of Beichuan county, China, experienced catastrophic destruction due to landslides induce by the 2008 Wenchuan earthquake. In consideration of the special location of the county town, this paper selected the landslides induced in the town as representative of large-scale near-rupture landslides, and quantitatively analyzed why the landslide damage was so destructive in the town by using strong motion data obtained from the Wenchuan earthquake in the Longmenshan area. Three methods were employed to estimate the landslide damage using strong motion data. (1) Peak ground accelerations (PGAs) on the hanging wall were used to evaluate the PGAs on the landslide sites in the town. The evaluated average PGAs were all greater than 1 g, indicating that the ground motion intensity was very strong during the earthquake. (2) Acceleration time histories, from another station with similar geological conditions to the town, were used to evaluate the critical acceleration changing range, and the estimated values showed the geological conditions were very susceptible to earthquakes. (3) Acceleration time histories, from two stations on the hanging and foot walls of the rupture, and near the town, were used to calculate the Newmark displacements, and all the evaluated displacements indicated that landslides were very likely. The results show that the slopes, susceptible to earthquakes in the Beichuan county town, were easily triggered under such strong ground-motion intensity and developed into large-scale catastrophic events.  相似文献   

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