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Received: 5 November 1998 / Accepted: 17 November 1999  相似文献   

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The original article to which this erratum refers was published in Earthquake Engineering and Structural Dynamics 1999; 28 :1405–1425.  相似文献   

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通过对福建数字遥测台网1999年所监测到的“9.21”台湾南投大震群和“9.23”福州小震群中的一系列较大地震进行分析,利用地震的时间和空间相对集中这一特点,有效地避开震源、路径及随时间变化的地质背景等因素对测定震级的干扰,发现了对测定台网平均震级影响的主要因素,不仅仅来自于台站地质背景的影响、台网使用的起算函数的影响,而且还发现在一定距离内地震周期也会对台网平均震级测定产生明显的影响。通过计算地动位移随震中距衰减的系数和起算函数随震中距增幅的系数,求出起算函数引起震级偏差的大小,提出了改进和消除这些影响的方法。  相似文献   

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A new probabilistic remediation simulation package, PREMChlor, was used to simulate the effect of contaminant source and plume remediation at a site contaminated by trichloroethylene (TCE). First, the PREMChlor model was calibrated to the plume using a deterministic approach to represent the site conditions prior to remediation activities, which occurred in 1999. The calibrated model was then used in a probabilistic mode to conduct a simulation of the effects of field source and plume remediation activities during the period after 1999. This probabilistic simulation considers uncertainties in seven key parameters: the initial source mass and concentration, the relationship between source mass removal and source concentration, the effectiveness of the source remediation, the groundwater velocity, the background plume degradation rate, and the plume treatment effectiveness. The simulation results compare favorably with the observed data collected after 1999, and show the influence of the remediation efforts on the plume.  相似文献   

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IntroductionShanxi is a significant seismic activity area in North China (WANG, 1995), named as Shanxi fault zone. One can see how important it is by the name. Up to now, a large number of achievements have been obtained from the studies mainly by the geological method. In order to improve the seismic research and carry out earthquake monitoring and prediction in this area, a GPS horizontal deformation monitoring network is established along the fault from the north to the south by the Se…  相似文献   

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The HadISST1 sea surface temperature data set is examined for two contrasting areas: the Chagos Archipelago, central Indian Ocean which has a small (approximately 3 degrees C) annual temperature fluctuation, and Abu Dhabi in the southern Arabian Gulf whose annual air temperature fluctuation of approximately 24 degrees C is the largest known for coral reef habitats. The HadISST1 data are shown to match air temperature records closely, both in terms of annual moving averages and residual analysis. Temperatures in 1998 caused massive mortality of corals in the Indian Ocean: sea surface temperature (SST) values causing this were 33.8 degrees C in the Arabian Gulf at a time when average daily air temperature was over 40 degrees C, while in Chagos the SST lethal to corals was 29.8-29.9 degrees C, when air temperatures peaked at about 31 degrees C. The HadISST1 record was searched back to 1870 for previous abnormal peaks: one of 29.7 degrees C was found for Chagos SST in 1972, though this did not cause coral mortality. Analysis of 12-month running means of the residuals from the annual cycle show that, between 1870 and 1999, the largest SST deviations occurred between October 1997 and May 1998 in Chagos and between August 1998 and July 1999 near Abu Dhabi. The event of 1998-1999 was the largest in these regions for at least 130 years. SSTs have risen over the last three decades at rates of about 0.22 degrees or 0.23 degrees per decade in both locations.  相似文献   

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An analysis and discussion of the main features and effects of the 1999global seismicity based especially on the inferred patterns of strong(Mw 7) earthquakes using NEIC/USGS data is presented.Based on the above data and their statistical features (see also Table 1)one may state that from the point of view of occurrence rate (number/yr)the 1999 global seismicity was fairly regular, but from the moment (orenergy) release standpoint it is well under the long-term average. The spacepartition was again rather typical and time distribution was quasi-Poissonian,noteworthy, the 1999 worldwide seismicity had an anomalously high deathtoll, to be discussed later. Two main new insights are brought by ouranalysis: (i) a (mega)quiescence along the whole south American segmentof circum-Pacific earthquake belt, which was inferred and rated asanomalous while it was underway and which, in retrospect, ended with thegreat (Mw = 8.4 HRV) 2001 Arequipa (Peru) event; (ii) an intriguingmonotonous rate decrease within only magnitude class 5.0 to 5.9 duringthe analyzed period (i.e., 1990–1999).  相似文献   

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川滇地区现今块体水平运动变形特征分析   总被引:2,自引:0,他引:2  
依据川滇地区1991,1999和2001年GPS测量数据,利用DDA正分析基本原理,结合现有的地质资料,对该地区近年来的水平构造运动特征进行了模拟分析,认为川滇地区水平运动整体速率在1999~2001年期间明显减弱;川滇决体主压应变以顺时针旋转为主,方向为SE—SEE;其南部是运动变形相对剧烈、易于积累能量的区域;未来一两年内,该地区地震活动水平不会太高。  相似文献   

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本文利用Sato单次散射模型,研究1999年至2007年辽宁海城-岫岩地区尾波Q值随时间的变化情况及1999年岫岩5.4级地震和2000年5.1级两次中强地震发生阶段该地区的尾波Q值变化。计算结果表明:该区在地震活跃阶段,Qc值随时间变化起伏较大,平均值相对较高,在岫岩5.4级主震前有短时升高现象,之后Qc值并没有明显的降低,直到强余震序列结束之后Qc值逐步降低,趋于平稳,通过对比该区在地震活跃阶段与平静阶段的Qc值变化,可以为未来该区的强震预测提供参考依据。  相似文献   

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林依再 《华南地震》2001,21(2):48-52
分析了1999年长乐筹东土壤氡气(土氡)变化特征,认为4-6月该测点土氡异常特征与9月21日的台湾南投Ms7.6级地震有关,7-9月的测值变化是由于降雨过多引起,并介绍了9月下旬后该测点的土氡变化特征。  相似文献   

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This paper presents an application of hydrological and hydraulic models for transferring instantaneous discharges from a water gauge station to budgeting sites on rivers. Calculations were done using the following models: MIKE NAM rainfall-runoff model and a hydrodynamic MIKE 11 HD model. The simulations were carried out for the catchment of Warta River and its tributaries for the multiyear period 1999–2009.  相似文献   

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 Glass fragments from three different hyaloclastites have been used to evaluate the range of cooling rates experienced by undersea volcanic deposits. We found that the glass fragments retain structures with a range of apparent quench rates from 25 to 0.15 K min–1. The most rapid cooling rates are interpreted to be those resulting from cooling of the lava near the water interface. Simple conductive cooling models produce a range of quench rates comparable to those of the more rapidly cooled samples. The very slow apparent quench rates are unlikely to result from simple linear cooling through the glass transition, because of the onset of crystallization; instead, they are indicators of a more complex thermal history that involves the annealing of glasses at temperatures within the glass transition interval for a dwell time sufficient to allow the relaxation of the glass to lower temperature structures. The thermal history recorded in these samples illustrates the complexity of eruptive processes and demonstrates that quench rates for natural glasses retain information relevant to more complex cooling models. Received: 10 February 1999 / Accepted: 9 September 1999  相似文献   

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The first analyses of PAHs in marine sediments within Rijeka Bay started in 1998 at three sampling sites offshore from the petroleum refinery facilities and were extended in 1999 to three more sampling points in front of the repair shipyard within the same east industrial zone. The small Svezanj cove, lying between the shipyard and the petroleum refinery was chosen as the reference point. The concentrations of PAHs were considerably higher in the shipyard environment (average: 3009-6314 μg kg−1 d.w.) in comparison to the petroleum refinery area (average: 279-919 μg kg−1 d.w.), while the PAHs load at reference point was close to the latter level (average: 717 μg kg−1 d.w.). The Phe/Anth and Flo/Py ratios indicate the dominant pyrogenic sources, except for the results from 1999 to 2000 with dominant petrogenic origin at some sites. A declining trend of total PAHs, and consequently toxicity indices was observed at all sites.  相似文献   

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简要介绍了美国ACI(1999)和AISC-LRFD(1999)、日本AIJ(1997)、英国BS5400(1979)、中国DBJl3-51-2003(2003)和DL/T5085-1999(1999)及欧洲EC4(1994)等设计规程中有关圆形截面钢管混凝土(以下简称圆钢管混凝土)压弯构件计算方法的特点,并将上述各方法及数值方法的计算结果和搜集到的圆钢管混凝土梁柱极限承载力实验结果进行了对比和分析。结果表明,在进行圆钢管混凝土梁柱极限承载力计算时,上述各规程提供的计算方法及数值方法均能较好地计算出构件的极限承载力,且计算结果偏于安全,其中,数值方法的计算结果与实验结果最为吻合,规程AISC-LRFD(1999)的计算结果最为安全。本文的研究结果可供进行圆钢管混凝土柱抗震设计时参考。  相似文献   

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ENSO和长江大水对天文因子的响应研究   总被引:5,自引:1,他引:4  
ENSO(厄尔尼诺和南方涛动的总称)对世界尺度的天气气候有影响,本文用概率论统计检验方法,查明长江大水与ENSO以及ENSO与天文因子的相关关系,并系统分析了三者之间的相关关系。结果表明:ENSO事件对天文物理主周期和天文特征有明显的响应,长江大水年对太阳活动特征、节气日的月相年变化和ENSO也有显著的响应关系。这些关系对长江大水的准确预测有重要价值。文中对天文物理因子对ENSO和大水的影响机理进行了探讨。  相似文献   

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No Abstract. .The following two amendments concern the above mentioned article that appeared electronically Online First on June13, 2005 (this issue, pp. 274–291).1. the first name of the author Cooper is Philip (and not Phillip).2. the correct grant reference number is EVK1-CT-1999-00032 (instead of: EVK1-CT-2002-00121).  相似文献   

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