Crustal structure of the Southwest Subbasin,South China Sea,from wide-angle seismic tomography and seismic reflection imaging     

Zhiteng?YuEmail author  Jiabiao?LiEmail author  Weiwei?Ding  Jie?Zhang  Aiguo?Ruan  Xiongwei?Niu 《Marine Geophysical Researches》2017,38(1-2):85-104

The Southwest Subbasin (SWSB) is an abyssal subbasin in the South China Sea (SCS), with many debates on its neotectonic process and crustal structure. Using two-dimensional seismic tomography in the SWSB, we derived a detailed P-wave velocity model of the basin area and the northern margin. The entire profile is approximately 311-km-long and consists of twelve oceanic bottom seismometers (OBSs). The average thickness of the crust beneath the basin is 5.3 km, and the Moho interface is relatively flat (10–12 km). No high velocity bodies are observed, and only two thin high-velocity structures (~7.3 km/s) in the layer 3 are identified beneath the northern continent-ocean transition (COT) and the extinct spreading center. By analyzing the P-wave velocity model, we believe that the crust of the basin is a typical oceanic crust. Combined with the high resolution multi-channel seismic profile (MCS), we conclude that the profile shows asymmetric structural characteristics in the basin area. The continental margin also shows asymmetric crust between the north and south sides, which may be related to the large scale detachment fault that has developed in the southern margin. The magma supply decreased as the expansion of the SWSB from the east to the west.  相似文献   

大规模空间数据处理模式和系统集成     

翟永  刘磊  顾学明  高景强  赵薇蔚 《测绘通报》2016,(9):99-102,122

随着地理信息需求推动下的空间数据采集能力的发展,空间数据的生产规模和数据量呈爆发式增长,直接带来了对大规模空间数据处理的需求。本文基于IT并行计算和大数据技术的发展成果,探讨了这些技术在大规模空间数据处理上的应用及相应的IT系统集成思路,提出了基于数据库的并行空间数据处理方法,并根据第一次全国地理国情普查项目需求作了深度验证和分析。  相似文献   

基于CPLD的石英水平摆倾斜仪CCD驱动设计     

占伟伟  卢海燕  蔡莉  王秀  杨振宇 《地震地磁观测与研究》2014,35(5):253-257

针对SQ-70D型石英水平摆倾斜仪光电转换器在实际使用中存在的驱动频率低、电路结构复杂不易调试等问题,研究基于CPLD的CCD驱动时序生成方法.仿真和测试结果表明,采用CPLD设计的驱动电路结构简单,稳定性高,能够满足TCD1500c典型工作频率的要求.同时,设置积分时间控制变量QINT,可以根据实际光照强度对CCD光积分时间进行灵活调整,提高仪器的环境适应性.  相似文献   

传统农林复合系统:一种全球重要文化遗产类型(英文)     

刘伟玮  李文华  刘某承  Anthony M.FULLER 《资源与生态学报(英文版)》2014,5(4):306-313

作为一种土地利用活动,传统农林复合系统已经经历了成百上千年的历史,并且依然发挥着重要的作用在世界上,特别是热带和亚热带地区。在全球变化和粮食安全等危机的时代背景下,传统农林复合系统受到越来越多政府和非政府组织的重视,因为传统农林复合系统具有重要的经济、生态和社会文化效益。这与全球重要农业文化遗产要求的特征也相一致,目前为止,已经有5个国家4个典型的传统农林复合系统被列为全球重要农业文化遗产。这些传统农林复合系统具有丰富的农业生物多样性,多重的生态系统服务功能,重要的社会文化价值,无论在区域还是全球水平上。目前传统农林复合系统面临一些威胁和挑战,如人口迁移、市场冲击、气候变化等,但是只要政府和非政府组织、社区、农民之间采取多种方式紧密合作,在未来的全球土地利用活动中,传统农林复合系统必将得到有效保护和推广。  相似文献   

Ocean data assimilation with background error covariance derived from OGCM outputs   总被引：6，自引：2，他引：4  

FU Weiwei  ZHOU Guangqing  WANG Huijun 《大气科学进展》2004,21(2):181-192

  相似文献   

城市综合与专业地下管线空间数据的差异性分析     

张书亮  储征伟  何源  张巍巍 《测绘通报》2013,(12):58-62

从管线数据来源及数据精度、数据模型、信息分类、数据语义等几个方面,本文对城市综合与专业两类地下管线空间数据进行了深入的差异分析,提出了差异形成的原因及消除差异的初步对策,以期对城市管线空间数据资源的集成、融合、共享、交换等技术提供支撑,并推动地下管线信息化统一标准的制订。  相似文献   

Enhanced resistance of Portunus trituberculatus to Vibrio alginolyticus by selective breeding     

母昌考  刘帅  宋微微  李荣华  王春琳 《中国海洋湖沼学报》2012,30(4):638-643

We established a line (screened) of Portunus trituberculatus by selectively breeding individuals that survived from challenge with Vibrio alginolyticus, and compared the response of screened and unscreened (control) P. trituberculatus challenged with V. alginolyticus. We measured superoxide dismutase, catalase, acid phosphatase, alkaline phosphatase, and peroxidase activity and the content of hemocyanin in the plasma and phenoloxidase activity in serum. The cumulative survival rate after 24-h challenge with V. alginolyticus was significantly higher in the screened crabs than in the unscreened crabs (P<0.05). T-SOD and PO activity were significantly lower in the screened stock than in the unscreened stock (P<0.05). POD, CAT, and ACP activity and hemocyanin content were significantly higher in the screened stock than in the unscreened stock. Our results suggest that the screened stock was more resistant to infection. Furthermore, the indices we measured may be used to evaluate the health state of P. trituberculatus.  相似文献   

景观格局与生态过程相互关系研究进展   总被引：9，自引：0，他引：9  

胡巍巍  王根绪  邓伟 《地理科学进展》2008,27(1):18-24

景观格局的形成反映了不同的景观生态过程,与此同时景观格局又在一定程度上影响着景观的演变过程。 空间格局、生态过程与尺度之间的相互关系是景观生态学研究的核心内容。本文对景观格局与生态过程的研究方 法、景观格局与生态过程相互关系等方面的国内外研究进展进行了综述。最后分析了目前景观格局与生态过程相 互关系研究中存在的问题与不足、未来的研究热点及发展趋势。  相似文献   

Heterogeneous strain regime in the eastern margin of Tibetan Plateau and its tectonic implications     

Guojie Meng  Xiaoning Su  Weiwei Wu  Jinwei Ren  Yonglin Yang  Jicang Wu  Chieh-Hung Chen  Nikolay V. Shestakov 《地震科学（英文版）》2015,28(1):1-10

The eastern margin of Tibetan Plateau is one of the most active zones of tectonic deformation and seismicity in China. To monitor strain buildup and benefit seismic risk assessment, we constructed 14 survey-mode global position system(GPS) stations throughout the northwest of Longmenshan fault. A new GPS field over 1999–2011 is derived from measurements of the newly built and pre-existing stations in this region. Sequentially,two strain rate fields, one preceding and the other following the 2008 MW7.9 Wenchuan earthquake, are obtained using the Gausian weighting approach. Strain field over1999–2007 shows distinct strain partitioning prior to the2008 MW7.9 Wenchuan earthquake, with compression spreading over around Longmenshan area. Strain field derived from the two measurements in 2009 and 2011 shows that the area around Longmenshan continues to be under striking compression, as the pattern preceding the Wenchuan earthquake, implying a causative factor of the sequent of 2013 MW6.7 Lushan earthquake. Our GPSderived dilatation shows that both the Wenchuan and Lushan earthquakes occurred within the domain of pronounced contraction. The GPS velocities demonstrate that the Longriba fault underwent slight motion with the faultnormal and-parallel rates at 1.0 ± 2.5 mm and 0.3 ± 2.2 mm/a; the Longmenshan fault displayed slow activity, with a fault-normal rate at 0.8 ± 2.5 mm/a, and a fault-parallel rate at 1.8 ± 1.7 mm/a. Longriba fault is on a par with Longmenshan fault in strain partitioning to accommodate the southeastward motion of eastern margin of the Tibetan Plateau. Integrated analysis of principal strain tensors, mean principal stress, and fast directions of mantle anisotropy shows that west of Sichuan is characterized as mechanically strong crust-mantle coupling.  相似文献   

近5年国际地球科学领域发展态势文献计量分析   总被引：2，自引：0，他引：2  

史静  朱薇薇  王鑫  肖仙桃  刘振锋  王欢  柴新夏 《地质学报》2017,91(12):2881-2888

本文基于Web of Science平台,以SCI-E数据库2012~2016年地球科学领域各年度居前10%的高被引论文为统计分析源,从国际地球科学研究论文的总体概况、研究的主要国家和机构、研究热点等方面对近年来地球科学发展态势进行文献计量分析,旨在为相关管理部门了解地球科学研究发展态势提供参考。  相似文献