共查询到20条相似文献,搜索用时 15 毫秒
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2015年5月19日9时58分,云南双柏、峨山一带出现密集的小震活动,并于6月14日发生ML4.1地震,形成显著的震群事件。本文利用双差定位法对该震群进行精定位,结果显示,重新定位后震中分布优势方向更明显,主要沿绿汁江南段断裂呈NNE向分布,震源深度为6~12km,其中,又以8~10km最具优势。与原始数据相比,重定位后残差明显减小,走时残差平方和由原来的0.303s降为0.034s,震源位置估算误差在EW方向平均为0.21km,在NS方向平均为0.173km,在垂直方向平均为0.175km;利用广义极性振幅技术(GPAT)方法,计算得到了24个ML≥2.5地震的震源机制解,结果显示,此次震群的震源机制类型绝大部分表现为正断性质,与该区历史地震多为走滑的结果有所差异。结合震区附近的龙门水库蓄水水位和该震群的频度-震级关系分析认为,双柏震群活动与水库蓄水过程密切相关,该震群的发生是龙门水库水体载荷加载而引起正断层产生错动的结果。 相似文献
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云南省区域数字地震遥测台网自1999年建成以来,记录了大量地震波形资料,从2000年1月至2006年2月,云南省及邻区共发生ML≥4.0地震168次,对这些地震的震级重新进行了测定,结果表明,对于云南省的区域地震,近震的体波震级ML和面波震级MS之间不满足昆明地震台网多年使用的MS=1.13ML-1.08这一换算公式,且发现ML也不一定大于MS。 相似文献
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The physical meaning of the truncated geoid, which is defined by the convolution of gravity anomalies with the Stokes function on a spherical cap of specified radius, has been studied by the authors. They investigated its relation to the density distribution, generating the surface gravity, and its potential use in inversion. Some progress results for simulated studies on point mass anomalies are presented.
The behavior of the truncated geoid is controlled by the radius of the integration domain, hereinafter referred to as the truncation parameter, which is treated as a free parameter. The change of the truncated geoid in response to the change of the truncation parameter was studied in the context of the simulated mass distributions. By means of such computer simulations we have managed to demonstrate the clear sensitivity of the truncated geoid to the depths, in addition to the horizontal positions, of point mass anomalies generating the synthetic surface gravity. The objective of this paper is to illustrate, with the help of computer simulation as the method of our study, the contribution of the truncated geoid to the solution of the gravimetric inverse problem. Further work towards employing the truncated geoid in gravity exploration is being conducted. 相似文献
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The results of the analysis of geomagnetic data synchronously recorded by the INTERMAGNET magnetic stations are presented. The goal of this research was to distinguish internal correlations between the data and to determine the optimal spatial interval of the geographical coordinates within which the efficient operation of only one magnetic observatory would be satisfactory in most occasions. The results of the observation of correlations between the geomagnetic data on a global scale are summarized and presented. Possible regions of application of these results are determined. 相似文献
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A New Method for Collecting Core Samples Without a Drilling Rig 总被引:1,自引:0,他引:1
A new piston sampler allows the collection of high-quality core samples from sand, silt or clay, up to depths of 18 meters. The sampler is operated by a one- or two-person crew without a drilling rig. The sampler and ancillary equipment fit easily into a half-ton truck, making this a highly portable sampling system. Other advantages include minimal mechanical disturbance and precisely known sample depth. Casing is not required to maintain an open corehole below the water table and drilling fluid is not used in the corehole, so the solids and pore water of the sample should not be contaminated by foreign fluids. High-quality samples for physical, geochemical, and microbiological characterization of the subsurface are easily obtained with this new device. 相似文献
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针对当前提取地震前兆数据易受到噪声干扰,且数据库中数据更新速度较慢的问题,提出基于空间相关的地震前兆数据库信息提取与数据更新方法。利用快速Myriad滤波器,引入滑动窗,选择窗口数据参与到计算中,将计算结果当作目前窗口滤波输出值,实现数据滤波,由此实现信息提取的去噪处理。依据初步滤波结果,将当前数据作为中心,并确定空间窗,在横向上进行相关数据统计。针对空间窗中各数据选取滑动时窗,并对其中的数据进行S变换,利用指数拟合的数据传输能力参数,获取缺失数据的填充修复参数。引入曲面加权函数对填充修复参数进行平滑,根据平滑之后的填充修复参数对S变换数据进行更新,实现空间相关下地震前兆数据库的数据更新。实验结果表明,所提方法的数据信噪比较高,数据更新时间较短。 相似文献
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Diving has become a booming branch of the tourism business. The economies of many countries with reef-lined coasts depend on high numbers of tourist divers; the resultant degradation of reefs by mechanical damage is accepted due to the short-term gain from the tourism business. Many activities of recreational diving do not particularly require coral reefs – any varied three-dimensional structure (e.g. a wreck) may be sufficiently attractive. The conflict between the needs of nature conservation and the economic interests of diving tourism can be mitigated by the formation of artificial underwater attractions as reef substitutes. Based on experiments in the northern Red Sea, we propose to deposit calcium minerals from the seawater in situ by electrolysis on a template of any desired shape. After transplantation of living coral fragments, a diverse community will develop. With this method different modules can be designed and formed on the seabed which can serve different needs such as diver training, environmental education and recreation as well as reef rehabilitation. By a combination of such modules, a recreational underwater park can be formed well suited to function as a DAD (diver aggregation device) and therefore, divert diver pressure from the natural reef. 相似文献
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A method was developed for the determination of organic halogens in water samples with the aim of minimizing matrix effects and simplifying the sample preparation technique commonly used. The method is based on the adsorption of organic halogens in modified hydrophilic divinylbenzene polymer columns and their elution with methanol. The adsorbent used enables rapid adsorption and desorption due to comparatively high operating flow rates and minimized solvent amounts. Furthermore, no additional reconcentration steps are needed. The methanol extract obtained is combusted with a standard EOX (extractable organic halogen) analyzer and the concentration of organically bound halogens is determined by microcoulometric analysis. The matrix effects are considerably reduced compared to the standard procedure (EN 1485) commonly used. A detection limit of 13 μg/L was established. 相似文献
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根据Andrews谱积分方法,采用近震源Brune圆盘模型,研究了2003年6月3日青岛崂山ML4.1地震序列破裂过程中应力降变化情况.结果表明,崂山序列主震静应力降为24 MPa,动态应力降大约为静态应力降的2.2倍;崂山序列余震应力降普遍低于5 MPa,约有80%的余震应力降小于1 MPa,显示出与主震断层面有关的余震低应力降现象,这说明主震的破裂与余震破裂过程之间存在明显的差别.这种现象与崂山序列的弱强度衰减一致,表明此次序列的余震属于低能量破裂过程.计算结果显示:①由Andrews谱积分方法得到的小震应力降与震级大小存在一定的相关性;②小应力降事件的静态应力降和动态应力降的比值普遍小于1,未发现明显的应力降之比与Brune应力降之间的关系. 相似文献
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2007年顺昌ML4.9地震余震的剪切波分裂现象 总被引:1,自引:0,他引:1
利用福建省地震局在顺昌ML4.9地震后布设的流动台网记录到的顺昌地震余震波形资料,应用SAM剪切波分裂分析方法,计算并得到顺昌余震的快波偏振方向和慢波时间延迟。结果表明,顺昌地区的快波偏振方向为北东向,与顺昌地区断裂带走向一致。 相似文献
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《Ground Water Monitoring & Remediation》1985,5(4):58-62
The recognition and assurance of the quality of ground water monitoring data are crucial to the correct assessment of the magnitude and extent of a ground water contamination problem. This article addresses an approach being developed to systematically evaluate the quality of a given set of ground water monitoring data collected during site investigation/ remedial action efforts. The system consists of a checklist of criteria, grouped into four major categories, which can be applied to laboratory or field measurements.
The first category, basis of measurement, considers whether the appropriate sampling, boring and/or analytical methods were chosen to obtain the measurement and the limitations of each method. Secondly, application of the method is assessed. This includes examination of the extent to which procedures were correctly performed, the use of quality control measures and calibration, and possible sources of error in the measurements. Third, evaluation of applied statistical methods is made, with consideration given to which statistics are meaningful in a given context and whether measurements are reproducible. The final category, corroborative information, considers whether independent data or other information are available that add credibility to the values measured.
In this approach, a "high quality" data value is defined as one in which accuracy is supported by meeting the preceding criteria. When accompanied by precision information, high quality data allow for defensible assessments and actions. This evaluation system is useful in developing monitoring programs and in guiding documentation of field and laboratory methods during data collection. It relies heavily on experienced judgment and can be catalyst for the beneficial exchange of knowledge and ideas among ground water professionals. 相似文献
The first category, basis of measurement, considers whether the appropriate sampling, boring and/or analytical methods were chosen to obtain the measurement and the limitations of each method. Secondly, application of the method is assessed. This includes examination of the extent to which procedures were correctly performed, the use of quality control measures and calibration, and possible sources of error in the measurements. Third, evaluation of applied statistical methods is made, with consideration given to which statistics are meaningful in a given context and whether measurements are reproducible. The final category, corroborative information, considers whether independent data or other information are available that add credibility to the values measured.
In this approach, a "high quality" data value is defined as one in which accuracy is supported by meeting the preceding criteria. When accompanied by precision information, high quality data allow for defensible assessments and actions. This evaluation system is useful in developing monitoring programs and in guiding documentation of field and laboratory methods during data collection. It relies heavily on experienced judgment and can be catalyst for the beneficial exchange of knowledge and ideas among ground water professionals. 相似文献