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Yixin Yu Xinhuai Zhou Liangjie Tang Wenxu Peng Dingyou Lu Weiguo Li 《Marine and Petroleum Geology》2009,26(8):1600-1607
Using the new high-quality 3D seismic data, this paper addresses the salt structures in the KL11 area of the Laizhouwan depression in the southern offshore Bohai Bay basin. In the study area, the salt in the Sha-4 Member of the Paleogene Shahejie Formation thickened, and then formed an S–N trending salt wall, which changes shape regularly along its trend from salt diapir to salt pillow. The change in thickness of the suprasalt layers record five growth phases of the salt wall from the Eocene to the Quaternary: (1) early diapirism, (2) active diapirism, (3) passive diapirism, (4) relative structural quiescence, and (5) arching. The evolution of the salt structures was mostly governed by the multi-phase compression induced by the dextral strike-slip of the Tan–Lu fault, which formed a restraining bend in the study area. There was an original passive stock in the south, which was later tectonically squeezed by E–W compression and became a diapir. As the shortening propagated to the north from the original stock, the salt pillow was created in the north. Relative structural quiescence then followed until the next phase of compression, which arched the thick roof of the salt wall. 相似文献
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A short convolutional differentiator (CD) for computing second spatial derivatives in the acoustic wave equation is presented. This differentiator is obtained by tapering the inverse Fourier transform of the band-limited Fourier spectrum of the second-derivative operator. This new filter has been applied to seismogram computations for inhomogeneous media and results are compared with the conventional high-order finite-difference (FD) and Fourier schemes. The operator can be progressively shortened at the model edges to reduce boundary artefacts. The CD method is superior to the conventional FD operator and comparable with the Fourier method in accuracy but faster to run. A strategy to reduce computation time by 20%, which exploits the localized nature of the operator, is given. The method is illustrated using simple 2D models. 相似文献
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采用“八五”地震预报攻关研究成果--地震算法复杂性C(n)值及地震强度因子Mf值时间扫描,对河南及邻区12次中等以上地震进行单项和综合分析研究。结果表明,对应率达80%,显示出这些方法具有一定的预报意义。 相似文献
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外强迫随时间的变化对于非平稳系统的影响十分重要,如何从该系统中重构或提取外强迫信息则成为研究其中动力学特征的关键所在。本文基于慢特征分析方法(Slow Feature Analysis,SFA)以连续系统(改变的Lorenz系统)为参考模型,分别讨论在周期型强迫、减弱的周期型强迫、指数衰减型强迫、伴随指数衰减的周期型强迫等条件下,SFA方法对模型中不同强迫信号的提取能力。结果显示,SFA方法能够提取作用于连续系统中的外强迫信息,其提取效果与外强迫的强度、噪声以及嵌入维数m有关:对于越弱的外强迫或者存在越强的噪声干扰,提取效果越差,提取信号中将出现虚假的高频波动;嵌入维数m的增大能在一定程度上提高外强迫信号的提取效果。试验还表明,作用在单一变量上的外强迫会将其驱动信息嵌入于系统中,因此,可以通过SFA分析方法从其他变量中提取其外强迫信号。 相似文献
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渤海海域莱州湾凹陷盐构造成因探讨 总被引:5,自引:4,他引:1
通过分析莱州湾凹陷盐构造特征,盐构造形成动力条件,探讨莱州湾凹陷盐构造成因,讨论了走滑背景下盐岩活动特点。分析表明,莱州湾凹陷盐层构造发育刺穿性盐株和枕状底辟,欠压实、超压破裂、潜伏走滑断层和楔形体的重力扩张促使了莱州湾凹陷盐岩早期流动;渐新世右行走滑阶段,走滑压扭作用下形成刺穿盐株;盐构造活动可分为沙三末期-沙一段沉积期盐流动阶段、中晚渐新世东营沉积时期盐刺穿阶段、中新世-第四纪盐构造再次活化三个阶段。走滑断裂作用下盐岩以流动为主,发育典型的刺穿型盐底辟。 相似文献
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西藏羊卓雍错流域水体水质评价及主要污染因子 总被引:4,自引:1,他引:3
水质是流域生态系统的重要指标,水质评价则是开展流域水体污染防治等工作的基础.基于2010-2014年羊卓雍错流域湖泊、河流水质及2012-2014年流域居民饮用井水、自来水水质监测资料,结合单因子污染评价法和内梅罗污染指数法,对流域水质现状进行分析和评价.结果表明,12处地表水体中,羊卓雍错和巴纠错受中度污染,其他水体清洁或尚清洁,硒及氟化物为主要污染因子;9处居民饮用水体中,自来水水质明显好于井水,但也仅有3处自来水达清洁标准,硒、铝及硝酸盐为主要超标项.污染因子通过水-土-植被-动物系统破坏流域生态环境、阻碍农业生产发展,并直接或间接影响人类身体健康.因此,必须做好流域环境的综合整治、控制农业面源污染、完善饮用水基础设施建设,同时继续加强水质监测. 相似文献
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渤海海域歧南断阶带古近系沉积体系及控制因素 总被引:1,自引:0,他引:1
在层序地层研究基础上,对歧南断阶带古近系砂分散体系与沉积体系构成及其主控因素进行分析。研究结果表明:歧南断阶带古近系沙三段至东营组地层可划分为2个二级层序和8个三级层序;可划分埕子口、沙垒田、沙中低凸起和燕山4个方向的物源体系;沉积体系演化经历了初始断陷期、主断陷期和断陷晚期3个阶段,发育辫状河三角洲、三角洲、扇三角洲、湖底扇等沉积体系类型;古地貌控制了砂体平面分布,其中古构造格架控制着相带分布,构造转换带控制着古水系,断裂坡折控制着砂体发育部位;复合基准面旋回控制着砂体垂向分布。预测海一断层附近至歧口17-1西侧坡折带和海四断层南侧三级台阶区是主要的潜力区。 相似文献