重庆地区重复地震识别及在数字地震台网定位评价中的应用     

汪建  张巡  杨亚运  陈凯  马伟  王同军 《地震地磁观测与研究》2020,41(2):37-43

利用重庆数字地震台网2010年1月至2017年12月的地震波形资料和观测报告,选出5个研究区1 251个M_L≥1.5地震进行波形互相关计算,识别出358对同时被2个地震台站记录且各台波形互相关系数(cc)不小于0.8的重复地震对,涉及342个地震事件,约占地震总数的27%。将筛选出的重复地震对用于定量判断地震目录中震相拾取误差及评估台网定位精度,结果显示:重庆数字地震台网的垂直定位误差约为3 km,水平定位误差约为5 km,Pg、Sg震相拾取误差分别为0.5 s和0.7 s;其中武隆区地震定位和震相拾取精度最高,綦江区最低。  相似文献   

Ab initio study of the high-pressure behavior of CaSiO3 perovskite     

Daniel Y. Jung  Artem R. Oganov 《Physics and Chemistry of Minerals》2005,32(2):146-153

Using density functional simulations, within the generalized gradient approximation and projector-augmented wave method, we study structures and energetics of CaSiO₃ perovskite in the pressure range of the Earths lower mantle (0–150 GPa). At zero Kelvin temperature the cubic CaSiO₃ perovskite structure is unstable in the whole pressure range, at low pressures the orthorhombic (Pnam) structure is preferred. At 14.2 GPa there is a phase transition to the tetragonal (I4/mcm) phase. The CaIrO₃-type structure is not stable for CaSiO₃. Our results also rule out the possibility of decomposition into oxides.

Daniel Y. JungEmail: Phone: +41-44-6323744Fax: +41-44-6321133

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1997年9月三水3.7和4.4级地震特征初析     

王正尚  康英 《华南地震》1998,18(1):125-129

对１９９７年９月２３日和２６日两次三水有感地震的特征进行了初步分析,认为这两次地震具有震前和震后地震活动水平低、面波发育和低震级高烈度等特性;震区的主压应力为北北西方向,两震的受力方向基本一致,但断层面解明显不同。  相似文献   

察尔汗盐湖盐田渗漏及其工程地质条件分析     

王石军 《化工矿产地质》1998,20(4):301-307

１９８１年以来对察尔汗盐湖三次渗漏试验结果表明,盐田渗漏是盐田土层与外界条件综合作用的结果,在盐田建设和生产管理过程中,应结合不同地点的土层特性、工程地质条件和其它有关条件,采取不同的处理措施。  相似文献   

淮河流域洪涝变化吸引子维数研究   总被引：15，自引：1，他引：14  

周寅康  包浩生 《地理科学》1998,18(4):362-367

淮河流域洪涝序列的功率谱表现出了较好的混沌谱特征,这是序列呈分形结构的内在原因。洪涝序列及其不同平滑序列的关联维数表明,序列平滑程度越大,关联维数越小,关联维数反映了序列所在系统的层次,是系统结构复杂性的重要量度,是 系统建模所需独立变量的控制参数。要恰当地描述淮河流域洪涝发生系数,需构造至少５个状态变量的动力学系统。  相似文献   

LiMn_2O_4的溶胶─凝胶─酯化法合成及性能Ⅱ　立方尖晶石的形成及其形貌     

尉继英  孙长敏  高海春 《盐湖研究》1998,(1)

以溶胶-凝胶-酯化法在220℃即可得到纯相的LixMn2O4（0.762＜x＜1.139）尖晶石粉体材料。它在880℃时发生立方相向四方相的转变：900℃－1000℃间,四方相渐变为正交相LiMnO2,过程中有Li2MnO3生成。应用SEM、TEM观测了材料的粘度及形貌,其粒度10－40nm,粒子间极易团聚成为1-206μm的团块。以BET法测其比表面为3.6m2／g。  相似文献   

干涉雷达在DEM测量中的精度影响及处理方法   总被引：1，自引：0，他引：1  

郭泾平  彭军  向茂生 《测绘学院学报》1998,(3)

干涉合成孔径雷达 (INSAR)为数字高程模型 (DEM)测量提供了一种新的手段。它具有同时获取三维信息、测量范围广、空间和高程分辨率高等优点。文中首先扼要介绍了干涉雷达的原理 ,然后重点讨论几个影响测量精度的因素及其处理方法 ,如相关、运动补偿、配准、相位展开等。  相似文献   

Crust and upper mantle heterogeneities in the southwest Pacific from surface wave phase velocity analysis     

R. Pillet  D. Rouland  G. Roult  D. A. Wiens 《Physics of the Earth and Planetary Interiors》1999,110(3-4):211-234

Direct earthquake-to-station Rayleigh and Love wave data observed on high gain broadband records are analyzed in order to improve the lateral resolution of the uppermost mantle in the southwest Pacific region. We used data of nine permanent Geoscope and Iris stations located in the southern hemisphere and nine other stations as part of two temporary networks, the first one installed in New Caledonia and Vanuatu (hereafter named Cavascope network) by ORSTOM and the EOST from Louis Pasteur University in Strasbourg (France) and the second one installed in the Fiji, Tonga and Niue islands (hereafter named Spase network) by Washington University in St. Louis (USA). In order to collect more significant details on the surficial structures, we included the analysis of short period waves down to 8 s. A multiple frequency filtering technique has been used to recover phase velocities of Rayleigh and Love waves for selected earthquakes with magnitude greater than 5.5 and with known centroid moment tensor (CMT). About 1100 well-distributed seismograms have been processed in the period range 8–100 s and corrections for topography and water depth have been applied to the observed phase velocities. The geographical distribution of phase velocity anomalies have then been computed using the tomographic method developed by Montagner [Montagner, J.P., 1986a. Regional three-dimensional structures using long-period surface waves. Ann. Geophys. 4 (B3), 283–294]. Due to a poor knowledge of dense, well-distributed, crustal thickness values and corresponding velocity models, we did not perform or speculate on the construction of an S-wave 3D velocity model; therefore, we limited this study to the interpretation of the phase velocity distribution. The location of phase velocity anomalies are well determined and the deviations are discussed within the framework of the geological context and compared with other tomographic models. At long periods, from 40 s to 100 s, our results agree well with most of previous studies: the tomographic imaging shows a large contrast between low and high phase velocities along the Solomon, New Hebrides and Fiji–Tonga trenches. The lowest phase velocity anomalies are distributed beneath northern and southern Fiji basins and the Lau basin (corresponding to the volume situated just above the dipping slabs), whereas the highest values are displayed beneath the Pacific plate and the eastern part of Indian plate downgoing under the North Fiji basin. At shorter periods, our results show that the phase velocity distributions are well correlated with the large structural crustal domains. The use of local temporary broadband stations in the central part of the studied area gives us the opportunity to observe surface waves showing well-dispersed trains, allowing extended velocity measurements down to 8 s although aliasing due to multipaths become important. The continental regions (Eastern Australia, New Guinea, Fiji islands and New Zealand) show low velocities which are likely due to thick continental crust, whereas the Tasmanian, D'Entrecasteaux, and the Northern and Southern Fiji basins are characterized by higher velocities suggesting thinner oceanic crust. Additional analysis including the anisotropic case and S-wave velocity inversion with depth is in progress.  相似文献   

非线性时间序列分析的最新进展及其在地球科学中的应用前景   总被引：14，自引：0，他引：14  

洪时中 《地球科学进展》1999,14(6):559-565

评述了非线性时间序列分析的最新进展,包括相空间重构、序列性质的鉴别、建模与预报,同时介绍了非线性时间序列分析在地球科学中的应用概况。  相似文献   

关于数字相位式测距仪的频率改正     

徐忠阳 《测绘学院学报》1995,(4)

本文在分析自动脉冲数字测相基本原理的基础之上，推出了不仅与测距频率有关，而且还与填充脉冲频率及低频测相频率有关的新的频率改正公式，并给出新的频率改正公式与传统频率改正公式之间等同的条件，即有锁相环路（或频率跟踪电路）的正常工作来保证。  相似文献