福建省5级地震的气候前兆     

顾延芬 《台湾海峡》1991,10(4):399-402

本文通过相关统计事实,初步探讨了福建5级地震前期的气象异常,提出了“气压、气温和雨量”模式,发现一次中强震前的1～3a间,先出现大面积降压和最高气温的异常增温,后出现大面积的干旱。这一时序演变,似可作为一次完整的孕震过程的气象前兆而用于中长期地震预报。  相似文献   

Successful colonization of the calanoid copepod Acartia tonsa in the oligo-mesohaline area of the Gironde estuary (SW France) – Natural or anthropogenic forcing?     

Valrie David  Benoît Sautour  Pierre Chardy 《Estuarine, Coastal and Shelf Science》2007,71(3-4):429-442

The copepod Acartia tonsa appeared in Europe in the first half of the 20th century and colonized progressively European seas and estuaries, possibly transferred from North Atlantic Coast of America. It had been reported in the polyhaline area of the Gironde estuary for a long time but was first recorded in the oligo-mesohaline area in 1983. Its abundance has been increasing significantly. High abundances of A. tonsa were reported since 1999, supplanting the abundances of its autochthonous congeneric species, Acartia bifilosa. This colonization was characterized by analyzing the mean seasonal variability: (1) for three 5-year periods corresponding to three different steps of A. tonsa appearance (1978–1982, A. tonsa was absent; 1988–1992, low abundances of the species; and 1999–2003, high abundances of A. tonsa) in the oligo-mesohaline area and (2) for three stations distributed along the salinity gradient during the recent period. The aim of this work was to define if this colonization was due to natural or anthropogenic forcing and to evaluate its possible impact on autochthonous zooplanktonic community.Both natural and anthropogenic forcings seem to explain the colonization of Acartia tonsa in the oligo-mesohaline area of the Gironde estuary. First records (1983–1988) could be due to marine water inputs caused by high values of the North Atlantic Oscillation index. The global warming which caused the increase of the summer warm period, the marinisation of the system and the local decrease of the turbidity should have been the key factors favoring the establishment of the species. Anthropogenic forcings as the establishment of the nuclear power plant which locally causes warmer conditions are also important factors explaining the differences of seasonal cycle observed between oligo-mesohaline area and other stations: the seasonal pattern of A. tonsa in the oligo-mesohaline area was indeed characterized by an autumnal peak of abundances which has been observed in other stations and in many North European estuaries, and by a second spring peak that had only been observed in Southern estuaries.The introduction of Acartia tonsa in the Gironde estuary significantly changed the seasonal pattern of autochthonous copepods, by limiting their seasonal abundances without affecting their long-term population stability. Finally, the successful colonization of A. tonsa had led to the spread of the seasonal zooplanktonic production which could have had an impact on fish and shrimp productions.  相似文献   

海洋沉积物声速与其物理-力学参数的相关性     

卢博  梁元博 《热带海洋学报》1991,(3)

通过对海洋沉积物声速及其物理-力学参数相关性的初步分析和研究,可以找到估算沉积物压缩波速Vp和切变波速Vs的经验式,最终为海底沉积物的性质进行声学遥测、为发展海底参数声遥感服务。本文给出了7个较为理想的回归方程。沉积物的物理参数与Vp有密切的关系;力学参数对Vs的预报有较大的作用。若增加物理参数作为修正项,其效果更佳。  相似文献   

Age and individual growth of Mesodesma mactroides (Bivalvia) in the southernmost range of its distribution     

Fiori  Sandra M.; Morsan  Enrique M. 《ICES Journal of Marine Science》2004,61(8):1253-1259

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Study of the growth of southern black and white monkfish stocks   总被引：1，自引：0，他引：1  

Duarte  Rafael; Azevedo  Manuela; Pereda  Pilar 《ICES Journal of Marine Science》1997,54(5):866-874

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向量损失函数下2个尺度参数估计的线性容许性     

赵建昕  张立振  于尚易 《中国海洋大学学报(自然科学版)》2003,33(6):983-988

在向量损失函数下 ,本文研究了含有尺度参数更一般线性模型中参数估计在线性估计类中的容许性 ,给出了估计可容许的充要条件  相似文献   

Determination of source parameters of small earthquakes in the east part of Guandong and south part of Fujian Province     

Jizeng Lin  Weiqiang Jiang  Youming Li  Shanghong Liang 《地震学报(英文版)》1992,5(3):469-480

Determination of source parameters of small earthquakes from amplitude ratios of and is studied in this paper when the distribution of the regional seismic network is skew to the earthquakes. The distribution of stations of the seismic network was to one side of the 17 earthquakes chosen from among 39 earthquakes in the east part of Guangdong and south part of Fujiang Province. The distribution of stations was classified into three types according to their relative positions with respect to the chosen earthquakes and the experiments of artificial data were done. Excellent results were also presented in various unfavourable conditions by using the method. As to the 39 small earthquakes recorded by the network in east Guangdong and south Fujian Province from 1982 to 1986, the results can be summarized as follows: Most of the fault planes of the earthquakes apear to be steep. Most of the principal compression stressesP and tensile stressesT are nearly horizontal, concentrating in the WNW-ESE direction. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinia,13, 420–429, 1991.  相似文献   

Seismic hazard in East Africa: An example of the application of incomplete and uncertain data     

Päivi Mäntyniemi  Andrzej Kijko 《Natural Hazards》1991,4(4):421-430

Earthquake hazard parameters maximum regional magnitude M _max and annual activity rate , and the b parameter of the Gutenberg-Richter relation have been evaluated for parts of East Africa. The applied maximum likelihood method permits the combination of both historical and instrumental data available (the catalog used here covers the interval 1880–1979). In addition, the uncertainty involved in magnitude determination and thresholds of completeness were taken into account. The hazard-parameter determination was performed for two study areas corresponding to segments of the eastern and western branches of the East African rift system. The results for these areas show differences that can be partly explained through the characteristics of the data.  相似文献   

基于Hoek-Brown准则的节理岩体能量参数估算          下载免费PDF全文

柴波  陶阳阳  杜娟  台大平  王禹 《地质科技通报》2020,39(1):78-85

岩体变形和破坏可以看作能量耗散和释放的过程.由于节理岩体结构复杂且难以开展室内试验,因此无法通过试验直接求取其能量学参数.基于Hoek-Brown准则和岩石能量理论,提出了节理岩体在临界状态能量学参数的估算方法.针对含贯通节理(或层面)岩体,通过修正岩块单轴抗压强度以体现贯通节理的方向效应.采用PFC3D分别模拟小尺寸岩样(Φ50mm×100mm)和大尺寸岩体(Φ2m×2m)的三轴压缩试验,通过岩石三轴试验结果拟合岩石数值模拟的细观参数并应用于节理岩体的模拟.根据节理岩体模拟得到应力应变曲线和能量流,验证了Hoek-Brown准则对节理岩体能量参数估算的合理性.  相似文献   

Sea‐surface hydrographical conditions off South Faeroes and within the North‐Eastern North Atlantic through MIS 2: the response of dinocysts     

CLÉMENCE CAULLE  AURÉLIE PENAUD  FRÉDÉRIQUE EYNAUD  SÉBASTIEN ZARAGOSI  DIDIER M. ROCHE  ELIZABETH MICHEL  SÉBASTIEN BOULAY  THOMAS RICHTER 《第四纪科学杂志》2013,28(3):217-228

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