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1.
在迎来中国数字地震台网运行１０周年之际,９个台站设备的二期技术改造工作业已胜利完成。目前,这些台站配置了先进的计算机系统－ＳＵＮ公司的ＳＰＡＲＣ系列台式工作站。其上安装了相应的地震分析软件,使得应用高质量的数字化数据进行地震分析成为可能,并弥补了模拟记录的许多不足。这无疑为台站工作人员及其它科研人员在台站现场进行地震分析工作,提供了十分便利的条件。但波形数据在ＳＵＮ工作站上的驻留是一个动态的过程, 相似文献
2.
新一代ＣＤＳＮ台站的地震信息管理,采用ＯＲＡＣＬＥ关系数据库系统。该系统主要由ＯＲＡＣＬＥ的核心,ＳＱＬ＊ＰＬＵＳ接口及各种实用程序组成（图１）。台站ＳＵＮ工作站系统配置的ＡＲＳ软件,是分析处理数字化地震资料的较为理想的应用软件。支持该软件的就是ＯＲ... 相似文献
3.
中国数字地震台网（ＣＤＳＮ）自１９８６年建成并投入运行以来,产出了高质量的数字化地震数据,台网的正常运行率平均为９５％。昆明台取得ＣＤＳＮ台站观测资料质量评分连续５年第一名的好成绩,在很大程度上取决于台站ＵＰＳ系统的维护和管理水平。我们针对ＵＰＳ电源... 相似文献
4.
本文介绍了全球遥测地震台网场地工作站的一般应用程序，配置于ＧＴＳＮ的场地工作站使台网所属成员能够分析和处理台站采集到的地震数据和健康状态信息的数据。场地工作站的运行与台站其他设备的运行是相互独立的。因此，它不妨碍数据采集和传输的进行。 相似文献
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6.
在新一代中国数字地震台网（ＮＣＤＳＮ）台站上，９０年代发展起来的地震发析软件ＡＲＳ将作为数字地震记录分析的常规工具的一个候选者。为使台站分析人员较快地掌握ＡＲＳ的使用方法，本文简述了用ＡＲＳ进行大震快速反应，针对震相到时、振幅及损角频率的测量的最低限度的操作步骤，并对有关问题进行了讨论。 相似文献
7.
经过中国国家地震局（ＳＳＢ）和美国地质调查局（ＵＳＧＳ）的通力合作，中国数字地震台网（ＣＤＳＮ）于１９８７年１０月开始运行，记有三分向短周期ＳＰ、宽频带ＢＢ、长周期ＬＰ和超长周期ＶＬＰ４种频带的数据记录。ＣＤＳＮ的网月带中记录了数字化的ＶＬＰ地震波形数据，网月带中含有网月带中记录了数字化的ＶＬＰ地震波形数据，网月带中含有网月带月志文件、台站月志文件和ＶＬＰ数据文件，其中ＶＬＰ数据文件有数据月志和Ｖ 相似文献
8.
ORACLE数据库系统在中国数字化地震台网的应用 总被引：1，自引：1，他引：0
中国数字化地震台网是全球数字化地震台网的一部分。设在国家地震局地球物理研究所ＣＤＳＮ的数据管理中心及其所属的北京、海拉尔、西安等１１个野外台站的地震信息管理系统的均采用ＯＲＡＣＬＥ数据。本文介绍了ＯＲＡＣＬＥ数据库在ＣＤＳＮ应用的情况。 相似文献
9.
本文在三维壳幔结构中两点射线追踪分步搜索算法的基础上,在物探中心地震方法研究室ＳＵＮ工作站上研究开发出可应用于非纵观测系统深地震测深资料人机对话三维分析处理的方法及软件。对研究区域的三角形剖分减少了人机对话过程中的工作量及人为干预,并用该方法以反演得到的华北块状模型作为初始模型,对该模型的剩余ＰｍＰ波残差进行了人机对话拟合。 相似文献
10.
本文研究了用于测井相分析识别岩性的人工神经网络模型设计并在ＳＵＮ工作站上用基于距离Ｄ－ｋｏｈｏｎｅｎＮＮ、Ｄ－ＢＰＮＮ两个网络建立了ＡＮＮ自动测井相分析系统。 相似文献
11.
《中国科学:地球科学(英文版)》2014,(12)
正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in both basic and applied research. 相似文献
12.
《中国科学:地球科学(英文版)》2014,(9)
正SCIENCE CHINA Earth Sciences,an academic journal cosponsored by the Chinese Academy of Sciences and the National Natural Science Foundation of China,and published by Science China Press and Springer,is committed to publishing high-quality,original results in 相似文献
13.
In natural waters arsenic concentrations up to a few milligrams per litre were measured. The natural content of arsenic found in soils varies between 0.01 mg/kg and a few hundred milligrams per kilogram. Anthropogenic sources of arsenic in the environment are the smelting of ores, the burning of coal, and the use of arsenic compounds in many products and production processes in the past. A lot of arsenic compounds are toxic and cause acute and chronic poisoning. In aqueous environment the inorganic arsenic species arsenite (As(III)) and arsenate (As(V)) are the most abundant species. The mobility of these species is influenced by the pH value, the redox potential, and the presence of adsorbents such as oxides and hydroxides of Fe(III), Al(III), Mn(III/IV), humic substances, and clay minerals. 相似文献
14.
Due to deleterious effects on non-target organisms, the use of organotin compounds on boat hulls of small vessels (<25 m) has been widely prohibited. The International Maritime Organisation (IMO) resolved that the complete prohibition on organotin compounds acting as biocides in antifouling systems should commence in 2008. As a result of restrictions on the use of organotin based paints, other antifouling formulations containing organic biocides have been utilised. This survey was conducted to assess the contamination of replacement biocides in the marine environment following the ban of TBT-based paints. Surface sediments samples were collected in the major ports and marinas along the France Mediterranean coastline (Cote d’Azur) and analysed for organotin compounds, Irgarol 1051, Sea-nine 211TM, Chlorothalonil, Dichlofluanid and Folpet. Every port and marina exhibited high levels of organotin compounds, with concentrations in sediments ranging from 37 ng Sn g−1dry wt in Menton Garavan to over 4000 ng Sn g−1dry wt close to the ship chandler within the port of Villefranche-sur-Mer. TBT degradation indexes suggested that fresh inputs are still made. Among the other antifoulants monitored, only Irgarol 1051 exhibited measurable concentrations in almost every port, with concentrations ranging from 40 ng g−1dry wt (Cannes) to almost 700 ng g−1dry wt (Villefranche-sur-Mer, ship chandler). 相似文献
15.
Ian R. Falconer 《洁净——土壤、空气、水》2005,33(1):64-71
Microcystins are cyclic heptapeptide toxins produced by a range of cyanobacterial genera. These cyanobacteria occur naturally in drinking water reservoirs subject to eutrophication, and in rivers and natural lakes. Because of the diversity of organisms, the toxins occur, from oligo‐mesotrophic lakes in North Temperate latitudes, to hypertrophic tropical ponds. The toxins are responsible for numerous cases of injury and death of domestic animals, and human poisoning from drinking water. The initial poisoning includes hepatic cell death. This leads to secondary effects from liver deficiency, including jaundice and photosensitisation. The toxic effects are largely due to inhibition of phosphatase enzymes, acting to regulate protein phosphorylation. The consequences include structural damage, apoptosis and, at lower concentrations, cell cycle effects and tumour promotion. As there is no clear evidence for direct carcinogenesis by microcystins, they are classed as non‐carcinogenic toxins in drinking water. Guideline Values for safe drinking water are derived from data for subchronic rodent toxicity, using the No Observed Adverse Effect Level (the highest dose giving no toxicity). To this dose are applied uncertainty factors, to calculate a Tolerable Daily Intake. On the basis of a standard bodyweight and water consumption the Guideline Value is determined for drinking water. For microcystin‐LR the WHO have set a provisional Guideline Value of 1 μg/L for drinking water. 相似文献
16.
The geomagnetic field and secular variation exhibit asymmetrical spatial features which are possibly originating from an heterogeneous thermal control of the Earth's lower mantle on the core. The identification of this control in magnetic data is subject to several difficulties, some of which can be alleviated by the use of core surface flow models. Using numerical dynamos driven by heterogeneous boundary heat flux, we confirm that within the parameter space accessible to simulations, time average surface flows obey a simple thermal wind equilibrium between the Coriolis and buoyancy forces, the Lorentz, inertial and viscous forces playing only a secondary role, even for Elsasser numbers significantly larger than 1. Furthermore, we average the models over the duration of three vortex turnovers, and correlate them with a longer time average which fully reveals the signature of boundary heterogeneity. This allows us to quantify the possibility of observing mantle control in core surface flows averaged over a short time period. A scaling analysis is performed in order to apply the results to the Earth's core. We find that three vortex turnovers could represent between 100 and 360 years of Earth time, and that the heat flux heterogeneity at the core-mantle boundary could be large enough to yield an observable signature of thermal mantle control in a time average core surface flow within reach of the available geomagnetic data. 相似文献
17.
Richard McCreary John McGaughey Yves Potvin Dave Ecobichon Marty Hudyma Harald Kanduth Alain Coulombe 《Pure and Applied Geophysics》1992,139(3-4):349-373
Located in northern Québec, the Lac Shortt Mine was a small gold mine consisting of a thin subvertical orebody which was mined in three main phases. High stress and rockbursting conditions were experienced when ore was extracted in the upper zone between the surface and a depth of 500 metres during the first two phases of mining. Severe rockbursts were experienced in late 1989 near the shaft and in the footwall development following a deepening of the mine shaft to a depth of 830 m and partial development of footwall drift access for the third phase of mining (the mining of the lower zone starting at a depth of 830 m moving upward toward a depth of 500 m). A 16-channel Electrolab MP250 microseismic system, with a Queen's University Full-Waveform piggy-back system, was installed underground at the site due to these problems.It was expected that the thinning sill would be subjected to an ever-increasing load as the thickness of the 500 m sill pillar decreased in the face of the mining excavation from below. A monitoring program consisting of the microseismic monitoring system, a range of conventional geomechanics monitoring tools as well as the undertaking of periodic seismic tomography surveys to assess the ongoing state of stress and rock mass condition within the sill was therefore warranted.The anomalously high-magnitude stress field and the brittle rockmass created a situation in which rockmass failure was common and violent. In the creation and thinning of the sill pillar, the location of banded microseismic activity was crucial in tracing rockmass failure and the associated ground control problems. Reliable source-location determination enabled the identification of areas of stress increase. The movement of the rockmass failure front could be followed, and was responsible for stope dilution, footwall and orebody development deterioration, and caving.Source-mechanism analyses gave accurate double-couple solutions for approximately forty percent of these events having at least ten recognizable polarities. Results suggested movement along vertical north-south striking or vertical east-west striking features. Underground observation of damaged access points showed that vertical north-south striking joints were experiencing failure.The microseismic activity, which was consistently concentrated close to the southwest and northeast corners of current production stopes, could be explained by a stress field oriented obliquely to the strike of the orebody, as measured prior to shrinkage of the sill pillar byin situ stress measurements and observed borehole overbreaks. The orientations of theP andT axes for the microseismic activity further confirmed that the stress field oriented obliquely to strike.While an increase in compressional-wave velocity of 2.3 percent, corresponding to a measured stress increase of approximately 10 MPa could be measured by repeated tomographic surveys, it was relatively small and only a factor of two or so above the velocity measured uncertainty. The relative insensitivity of thein situ rock mass modulus to the applied stress is believed to be largely due to the rockmass discontinuities being relatively closed prior to stress increase, as substantiated by the small deformations seen by the extensometer and borehole camera. This situation existed because of the very high pre-mining stress level.The experimental demonstration that the rock could not absorb substantially increased load through the mechanism of discontinuity closure or tightening (which would be reflected in the modulus) may be evidence in itself of potentially burst-prone ground, such as encountered at Lac Shortt. 相似文献
18.
《水文科学杂志》2013,58(4):704-712
Abstract The upper Niger and Volta rivers exhibit a great and highly contrasting variability of inter-annual runoff. The Bani River, the largest tributary to the Niger River in Mali, shows a dramatic decrease in runoff after the 1970s, with the result that many boreholes in the region have dried up since the drought began. In contrast, the Nakambe River (Upper Volta basin, in Burkina Faso) shows an increase in runoff for the same period, leading to unexpected flood peaks that damaged infrastructures. The contribution that the groundwater and its variability make to surface runoff variability is assessed in this study by comparing the data of the national groundwater monitoring networks of Mali and Burkina Faso to surface runoff. Several variables are compared at the basin scale: the date of the maximum level of the water table, the annual rainfall, discharge, low flows and depletion coefficients. Variability in the low flows of the Bani River is well correlated to a decrease in the water table. Since 1970, the greater decrease in runoff in comparison to the rainfall decrease is due to a reduction in the baseflow, related to the cumulated rainfall deficit. Concerning the Nakambe River, the runoff increase is not supported by a water table increase, but is due to the increase in runoff coefficient related to land degradation. 相似文献
19.
The inability to detect the presence of viable Helicobacter pylori bacteria in environmental waters has hindered the public health community in assessing the role water may play in the transmission of this pathogen. This work describes a cultural enrichment method coupled with an H. pylori‐specific PCR to identify these bacteria in water. While far from perfected at the present time, this represents an exciting new approach to studying the significance of water as a transmission mechanism for H. pylori. Evidence is presented that indicates culturable H. pylori bacteria were found using this enrichment/PCR method in a local groundwater source. 相似文献
20.
Response spectrum predictions for potential near-field and far-field earthquakes affecting Hong Kong: rock sites 总被引：1，自引：0，他引：1
N. T. K. Lam A. M. Chandler J. L. Wilson G. L. Hutchinson 《Soil Dynamics and Earthquake Engineering》2002,22(1)
To realistically assess the seismic risk relating to built infrastructures in Hong Kong and in the neighbouring coastal cities of southern Guangdong province, it is necessary to predict ground shaking induced by different earthquake scenarios with good accuracy. A companion paper has described the modelling of the spatial and temporal distribution of the diffused seismic activities in the region, based on the newly-developed ‘Expanding Circular Disc’ (ECD) method. Representative Magnitude–Distance (M–R) combinations for both near-field and far-field earthquakes (in relation to Hong Kong) have been derived using the ECD method. The present paper describes the modelling of the response spectrum on rock sites associated with the predicted M–R combinations, using the Component Attenuation Model (CAM) that was also developed recently by the authors, based on stochastic simulations of the seismological model. The significant effects of soil resonance on the response spectrum are described in a separate publication.The accuracy of CAM in modelling ground motion properties on rock sites has been tested here by comparisons with (i) strong motions recorded in Taiwan and South China from the 1999 ‘Chi-Chi’ earthquake in Taiwan (M=7.6), (ii) motions recorded in South China from another earthquake occurring in the southern Taiwan Strait in the same year (M=5.1), and (iii) historical seismic intensity data obtained within South China. The overall capability of CAM in modelling both near-field and far-field attenuation has been shown to be unmatched by existing empirical models. Results of the comparison studies confirm the accuracy of CAM, particularly within an epicentral distance of 300–400 km.This study shows that the developed serviceability response spectra (i.e. at short return periods) are controlled mainly by the earthquake recurrence behaviour of major distant seismic sources. In contrast, the ultimate response spectra (i.e. at long return periods) relate to events with magnitudes close to the maximum credible earthquake (MCE) limit, the effect of which may also be represented by the Characteristic Response Spectrum (CRS). Both types of earthquake scenario can be significantly affected by the regional crustal properties. The proposed response spectrum envelopes have been compared with previously developed recommendations, and a critical review has been conducted. The intrinsic advantages of the ECD–CAM modelling approach have been highlighted, emphasising its directness and transparency when compared with the more complex process required to implement traditional Probabilistic Seismic Hazard Assessment (PSHA). 相似文献