新疆喀什及邻近区域流动地磁和流动重力联合分析研究     

陈丽  刘代芹  李杰  艾力夏提&#;玉山  李桂荣  李瑞  丁新娟  孙小旭 《震灾防御技术》2017,12(2):423-432

利用2014-2015年南天山地区45个测点的2期流动地磁资料，分析喀什及邻近区域相邻两期岩石圈磁场的动态变化特征，同时，利用2014-2016年170个测点的4期流动重力资料，分析不同时间尺度的重力场动态变化信息。研究表明:皮山6.5级地震的发生对皮山一带的地磁矢量分布特征影响较大，总磁场强度、磁偏角和磁倾角均有变化；无论是半年尺度还是一年尺度的重力变化图像都显示乌恰一直处于重力变化的高梯度带；综合多手段的观测资料对震情形势的判定更为准确。  相似文献   

2017年精河MS6.6地震前重力变化特征分析     

艾力夏提&#;玉山  李瑞  刘代芹  王晓强  朱治国  李杰  刘立人  苏力坦&#;玉散  陈丽 《中国地震》2017,33(4):749-756

利用新疆地区北疆测网2015～2017年观测的共4期流动重力资料，分析研究区半年、1年尺度重力变化特征，并采用小波分解方法，对2017年8月9日精河M_S6.6地震前重力变化异常进行分解，分离了不同深度的重力异常。结果表明，震中附近的精河地区从2015年开始一直处于重力负值变化，同时，震中周围的重力正值变化集中区逐步向震中地区迁移，地震发生前震中以南60km处出现重力变化零值线，并且零值线两侧的重力累积变化量达到70μGal。小波分解后，4阶细节图较好地反映了精河地震前的重力异常，其与地震孕育发生有较好的对应性。  相似文献   

Gravity and magnetic investigation on the distribution of volcanic rocks in the Qinggelidi area,north‐eastern Junggar Basin (north‐west China)     

Yang Yushan  Li Yuanyuan  Liu Tianyou 《Geophysical Prospecting》2012,60(3):539-554

A detailed investigation on the location of magmatic intrusions in the Carboniferous strata of the Qinggelidi area, north‐eastern Junggar Basin, is presented based on the interpretation of gravity and magnetic data constrained by petrophysical data, seismics and surface geology. The wavelet multi‐resolution analysis based on the discrete wavelet transform is adopted to the regional‐residual separation of gravity and magnetic anomalies. A power spectrum analysis is applied to estimate the source depths corresponding to different scales. A comparative analysis on the characteristics of local gravity and magnetic anomalies improved our understanding of volcanic rock distribution in the Carboniferous strata. Generally speaking, in total 75 anomalies are recognized, among which 23 are inferred to be the responses of basalts, diabases and andesites with high density and strong magnetization. Twelve anomalies are assumed to be caused by andesites, rhyolites and volcanic breccias with medium‐low density and high magnetization. There are still five anomalies that are believed to be generated by volcanic tuffs with low density and weak magnetization. Lastly, four cross‐sections in 3D gravity and magnetic modelling are displayed to provide a more thorough image of volcanic rocks in our study area.  相似文献   

Erratum to: Molecular diversity of Enteromorpha from the coast of Yantai: a dual-marker assessment     

刘海燕  刘正一  王寅初  赵玉山  秦松 《中国海洋湖沼学报》2014,32(1):239-239

<正>Erratum to:Chinese Journal of Oceanology and Limnology Vol.31 No.6,P.1210-1215,2013http://dx.doi.org/10.1007/s00343-013-3045-7The supporting grant information on the footnote of the original version of this article needs to be altered and updated.The new information is given below.  相似文献   

尼日尔三角洲的重力滑动构造          下载免费PDF全文

苏玉山  张光亚  王桐  李程  赵岩  李曰俊  黄彤飞  赵甜玉  高艳艳 《地质科学》2019,54(2):411-422

位于南大西洋东岸被动大陆边缘之上的尼日尔三角洲发育一大型重力滑动构造。自非洲大陆向南大西洋方向,该重力滑动构造可以划分出前缘挤压构造变形区和后缘拉张构造变形区。前缘挤压构造变形,形成褶皱冲断带;后缘拉张构造变形,形成堑垒构造;两者之间的过渡带发育滑脱褶皱。三角洲沉积的时代为始新世—第四纪,地层剖面自下而上依次是海相页岩(Akata组)、近海三角洲相砂岩—页岩互层(Agbada组)和陆相冲积砂岩(Benin组)。3个岩石地层单元都是穿时的,向大洋方向变新。重力滑动构造的主滑脱面位于Akata海相页岩中。根据生长地层、不整合以及卷入变形的地层时代,重力滑动构造起始于约12 Ma,伴生有广泛发育的泥构造。重力滑动构造的形成可能与新生代喀麦隆火山带(Cameroon volcanic line)的火山活动有一定的关系。  相似文献   

Recording-based identification of site liquefaction   总被引：2，自引：0，他引：2  

胡聿贤张郁山  梁建文Ray Ruichong Zhang 《地震工程与工程振动(英文版)》2005,4(2):181-189

Reconnaissance reports and pertinent research on seismic hazards show that liquefaction is one of the key sources of damage to geotechnical and structural engineering systems. Therefore, identifying site liquefaction conditions plays an important role in seismic hazard mitigation. One of the widely used approaches for detecting liquefaction is based on the time-frequency analysis of ground motion recordings, in which short-time Fourier transform is typically used. It is known that recordings at a site with liquefaction are the result of nonlinear responses of seismic waves propagating in the liquefied layers underneath the site. Moreover, Fourier transform is not effective in characterizing such dynamic features as time-dependent frequency of the recordings rooted in nonlinear responses. Therefore, the aforementioned approach may not be intrinsically effective in detecting liquefaction. An alternative to the Fourier-based approach is presented in this study, which proposes time-frequency analysis of earthquake ground motion recordings with the aid of the Hilbert-Huang transform （HHT）, and offers justification for the HHT in addressing the liquefaction features shown in the recordings. The paper then defines the predominant instantaneous frequency （PIF） and introduces the PiF-related motion features to identify liquefaction conditions at a given site. Analysis of 29 recorded data sets at different site conditions shows that the proposed approach is effective in detecting site liquefaction in comparison with other methods.  相似文献   

Hilbert spectrum and intrinsic oscillation mode of dynamic response of a bilinear SDOF system： influence of harmonic excitation amplitude   总被引：1，自引：0，他引：1  

张郁山梁建文  胡聿贤 《地震工程与工程振动(英文版)》2005,4(1):17-26

Under harmonic wave excitation, the dynamic response of a bilinear SDOF system can be expressed by the Hilbert spectrum. The Hilbert spectrum can be formulated by (1) the inter-wave combination mechanism between the steady response and the transient response when the system behaves linearly, or (2) the intra-wave modulation mechanism embedded in one intrinsic mode function (IMF) component when the system behaves nonlinearly. The temporal variation of the instantaneous frequency of the IMF component is consistent with the system nonlinear behavior of yielding and unloading. As a thorough study of this fundamental structural dynamics problem, this article investigates the influence of the amplitude of the harmonic wave excitation on the Hilbert spectrum and the intrinsic oscillatory mode of the dynamic response of a bilinear SDOF system.  相似文献   

利用可提取性磷脂表征沉积物中微生物的生物量   总被引：4，自引：0，他引：4  

陈进才  林庆梅  郑天凌  李玉桂  黄玉山  谭凤仪 《台湾海峡》1999,18(4):407-412

应用ＧＣ－ＭＳ技术,分析了深圳大亚湾大鹏澳及厦门岛南岸海域沿岸几个站位沉积物中可提一磷脂酯结合态脂肪酸的含量和组成成份;同时采用吖啶橙荧光染色计数法测定了这些的中细菌的丰度、重担一。结果表明,在这些沉积物中细菌的生物量与磷脂酯结合态脂肪酸的组份的含量有着正相关关系。说明在环境生态研究中,可提取性磷脂作为海洋和河口沉积物中微生物生物量的生物标志物的可行性。  相似文献   

南海北部古俯冲带的位置及其对南海扩张的控制   总被引：3，自引：0，他引：3  

闵慧  任建业  高金耀  左玉山 《大地构造与成矿学》2010,34(4)

为了确定南海北部古俯冲带的具体位置,作者利用美国LCT综合反演软件对收集到的重磁数据进行处理解释,结果显示在南海北部从台湾西南部到一统暗沙隆起,即沿南海海盆北部陆坡为一条布格重力异常水平梯度峰值带,指示了古俯冲带的具体位置;其北部的高磁异常代表了与之对应的古火山弧。深反射地震资料也验证了南海北部陆坡位置存在古俯冲带,钻井资料显示俯冲带存在的时代为晚侏罗世到早白垩世。据此绘制了南海地区晚中生代到现今的构造古地理演化图,指出南海的扩张应与晚中生代俯冲带这个先存的软弱带有关,南海海盆正是从古俯冲带的位置开始扩张。  相似文献   

第一次全国水利普查与全国水文统计年报数据对比分析研究     

李玉山  任小凤 《水文》2012,32(6):73-74,33

通过对第一次全国水利普查中河湖基本情况普查、行业能力建设情况及全国水文统计年报数据的作用、目的、范围、方法和指标体系等进行对比研究,进一步分析了水利普查与统计年报工作的关系,有助于帮助水文统计人员进一步认识和理解水利普查与水文统计年报的工作衔接问题。  相似文献