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91.
Study on distribution characteristics of strong earthquakes in Sichuan-Yunnan area and their geological tectonic background 总被引:2,自引:0,他引:2
Introduction Both Sichuan and Yunnan are provinces with more earthquakes. Based on catalogue of strong earthquakes in China compiled by the Prediction Department of China Earthquake Administration, there are 639 M5.0 earthquakes during 26 B.C.~A.D. 2001. Among them, 475 are M=5.0~5.9 events, 124 are M=6.0~6.9 events, 39 are M=7.0~7.9 events, and one is M=8 event occurred in Sichuan and Yunnan area. Here is one of the areas where seismic activities are most active in China. Sichuan-Yun… 相似文献
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巴基斯坦北Potwar形变区是西北喜马拉雅褶皱逆冲带前陆区的一部分,绘制了该区的地震活动性图. 与相邻地区比较,该区地震并不活跃,没有显示出与地表地质构造相关的清晰地震活动图象. 做出了4次地震的震源机制解. 结果表明,有3次地震是左旋走滑断层活动,另一次地震是逆断层活动. 地震震源机制解的P轴方向为NW-SE和NE-SW. 现今的构造形变很可能也包括基底的形变. 相似文献
94.
Upgrading the Earthquake Catalog of Switzerland (ECOS) included revising the earthquake of 1720. This change has major importance for history and seismology.Although that quake has been the subject of several publications, none was based on critical methods. This re-evaluation of the event is built upon a new and more reliable database established after investigating archives and libraries. Using data from such historical sources, we assigned new site intensities, adopting the criteria established by the European macroseismic scale EMS 98 (Grünthal, 1998).We discovered that the event had been assigned an overestimated intensity, due to interpretation errors in former earthquake catalogs and compilations. We recommend reducing the intensity from I0= VIII to I0= VI (EMS 98). The moment magnitude is given as MW= 4.6. Since the event had been considered the largest for its respective area, downgrading it now will influence the seismic hazard assessment for this region. 相似文献
95.
Introduction Sichuan-Yunnan region is a major area with frequent strong earthquakes in Chinese mainland, especially the middle-southern segment of South-North Seismic Zone, where many strong earth-quakes occurred in history. In the past 30 years, Sichuan-Yunnan region has two seismically active periods: one is from Tonghai earthquake in 1970 to Longling-Songpan earthquake in 1976, the other is from Lancang earthquake in 1988 to now. During this two periods, the M=7.7 Tonghai, M=7.1 Dagua… 相似文献
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内蒙古东部闹牛山铜矿成矿地质背景分析 总被引:4,自引:0,他引:4
通过对闹牛山铜矿区与成矿有关的次火山岩岩石化学分析,以及对矿区火山一次火山岩微量元素、稀土元素的分析,结合相关的铅同位素分析,综合分析了该矿床的成矿地质背景。认为:闹牛山铜矿床构造环境属于大陆边缘裂陷带的局部隆起区,成矿火山岩浆为钙碱性,其来源于地壳深部或上地慢,并有上部地壳物质混染。 相似文献
98.
Management of Historical Seismic Data Using GIS: The Island of Ischia (Southern Italy) 总被引:1,自引:0,他引:1
This paper presents the results of the use of Geographic Information Systems (GIS) inmanaging information on the effects of earthquakes in historical times on the island ofIschia. The unpublished sources on the Casamicciola earthquake of 28 July 1883 andthe extensive bibliography documenting the island's seismicity from 1228 showed theneed to proceed towards a type of data storage that would also allow management ofthe same data. Application of GIS techniques allowed us to insert, extract, handle,manage and analyse the data for the zoning of seismic damage on the island of Ischia.The end-product consists of information layers, such as maps of isoseismals, the damage, and hazard involved, as well as numerical tables associated to maps.The study was developed using GIS Arc-View 3.2 software (ESRI) and is structured inthematic vectorial levels and rasters. The overlapping themes constitute a cartographicdata base of the island. The damaged sites are located on a map at a scale of 1:10,000,with all the information on the 1883 earthquake (total number of houses, number ofcollapsed houses, collapsed or damaged rooms, photographs, plans of buildings, etc.)being associated to each site. The GIS is structured in such a way as to be able to beintegrated with further georeferenced data and with other databases. It is thus able toprovide support both for in-depth analyses of the dynamic processes on the island andextend the assessment to other natural risks (volcanic, landslides, flooding, etc.). 相似文献
99.