2006年青海玉树地震类型和发震构造分析          下载免费PDF全文

都昌庭  李文巧  卢宁  哈辉  才扎西  达杰 《地震工程学报》2007,29(3):271-274

2006年7月18和19日在青海玉树相继发生了5.0、5.6和5.4级地震。本文通过玉树地震台记录的地震波形及青海省地震台网监测结果分析该地震事件属于震群型地震;通过现场考察及宏观烈度区、余震分布和震源机制解、区域构造分析认为发震构造为乌兰乌拉湖-玉树构造带。  相似文献   

High-resolution provenance determination of construction-stone: A preliminary study of Corinthian oolitic limestone quarries at Examilia     

Chris L. Hayward 《Geoarchaeology》1996,11(3):215-234

At least 1.5 × 10⁶ m³ of oolitic limestone from the Corinthia was quarried during antiquity, mainly for construction. Previously, it has only been possible to speculate about the sources of oolite in ancient constructions because of its uniformity on the macroscopic scale. However, thin section petrography demonstrates a considerable degree of petrographic variation within the oolite of one group of quarries at Examilia, 4.5 km ENE of Ancient Corinth. Variation in the characteristics of the ooids and the amount and types of noncarbonate grains in the oolite from different quarries permit the identification of five petrographically distinct zones in the Examilia quarries. This offers great potential as a high resolution provenancing tool, and the data have numerous other archaeological applications. Following these results, the work has been extended to become a comprehensive study of all Corinthian oolite quarries. © 1996 John Wiley & Sons, Inc.  相似文献   

华南汛期持续性降水特征及其与30~90 d大气低频振荡的联系北大核心          下载免费PDF全文

鲁围  朱益民  哈瑶 《气象科学》2023,43(2):207-214

利用全国756站逐日降水资料以及NCEP/NCAR再分析资料,研究了1961—2011年我国东部汛期持续性降水30~90 d低频变化特征及其与大气低频振荡的联系。结果表明,华南地区降水偏多型是汛期持续性降水低频变化的主导模态。对流层低层位势高度负异常和气旋型环流异常,以及高层略向北偏移的环流异常为华南汛期持续性降水低频变化提供了大尺度形势场。当西太平洋副热带高压脊线维持在22°N附近时,来自孟加拉湾和南海的水汽输送维持了华南地区汛期持续性降水活跃位相,向东北传播的副热带大气低频振荡系统对华南汛期持续性降水具有调制作用。此外,华南汛期降水低频变化还具有南北迁移的经向演变特征。  相似文献