川滇交界中段历史强震及其活动特征     

黄圣睦 《四川地震》1994,(4):25-33

本文在详细补充调查和充分整理前人资料基础上，对川滇交界中段的其中６次强震进行了等烈度图编制，并对川滇菱块东界大地震的等烈度线分布特征进行了研究，按照构造孕育与发震扩展的思路，探讨了川滇交界中段的中长期地震危险性。  相似文献   

中国地震历史资料的信息开发与利用   总被引：7，自引：1，他引：7  

宋治平  梅世蓉 《地震》1995,(1):12-19

本文对全国历史地震资料的有用信息作了进一步的开发和利用，按统一方法处理了大量有感以上地震的文字记载，确字每个独立地震的时间与地点；分区求得地震的有感区长半径与震级的关系式；确定了历史有感地震的最低震级为４；取得了８０００余次有感地震垢基本参数；用等震线测定了巨大地震的参数；将有感强震目录统编成全国与几个大区Ｍ≥４．０地震目录，按《地震学地震预报实用程序系统》（ＥＰＳＥＩＳ）的格式要求建库；同时编制  相似文献   

Rupture zones in the area of the 17.08.99 Izmit (NW Turkey) large earthquake (Mw 7.4) and stress changes caused by its generation   总被引：1，自引：0，他引：1  

E.E. Papadimitriou  V.G. Karakostas  B.C. Papazachos 《Journal of Seismology》2001,5(2):269-276

The M_w 7.4 Izmit earthquake of 17 August 1999 struck a part ofthe North Anatolian fault in the area of Izmit Bay (NW Turkey). Historicalinformation shows that the fault which moved during the generation of thisearthquake consists of two fault segments moved during the generation oflarge (M 7) earthquakes in 1719 and 1754, respectively. Since then onlythe central part (between Izmit and Lake Sapanca) of this fault ruptured bythe generation of a smaller shock (M = 6.6) in 1878.The spatial stress variations based on the calculation of changes in theCoulomb Failure Function (CFF) associated with this earthquake aresupported by the distribution of strong aftershock foci. Large positive valuesof CFF to the east and west of the mainshock epicenter are inagreement with the notion that secondary faults were triggered there by thegeneration of the main event. Large positive values of CFF are alsoobserved in the adjacent western fault segment where the 1766 event wasgenerated, evidencing the occurrence of the next strong earthquake in thissegment.  相似文献   

Lightning optical pulse statistics from storm overflights during the Altus Cumulus Electrification Study   总被引：2，自引：0，他引：2  

D.M. Mach  R.J. Blakeslee  J.C. Bailey  W.M. Farrell  R.A. Goldberg  M.D. Desch  J.G. Houser 《Atmospheric Research》2005,76(1-4):386

The Altus Cumulus Electrification Study (ACES) was conducted during the month of August 2002 in an area near Key West, Florida. One of the goals of this uninhabited aerial vehicle (UAV) study was to collect time resolved optical pulse data from thunderstorms. During the month long campaign, we acquired 5256 lightning generated optical pulses. Most of these observations were made while quite close to the top of the storms. We divided our data into two amplitude groups based on prior NASA U2 aircraft optical data and the pulse characteristics. The group of strong pulses with radiance greater than 2.1 mW m^{− 2} sr^{− 1} had mean and median 10–10% optical pulse widths of 770 and 740 μs, respectively, 50–50% pulse widths of 399 and 355 μs, respectively, and 10–90% risetimes of 292 and 260 μs. These values are very similar to the previous U2 based optical results The other group of pulses consisting of slightly more than a quarter of the total pulses observed had radiances less than the minimum values detected in the U2 study. These weak pulses were narrower than the strong pulses with 50–50% mean and median values of 199 and 160 μs, respectively. Only 12% of the flashes observed contained only weak pulses. The source of these weak pulses is unknown, but we suspect that some are artifacts of the close proximity of the aircraft to cloud top.  相似文献   

Hard as the Rock Itself: Place and Identity in the American Mining Town by David Robertson     

David J. Nemeth 《The Professional geographer》2007,59(4):558-559

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陈代光教授对岭南历史地理研究的贡献     

许桂灵  司徒尚纪 《地域研究与开发》2007,26(2):124-128

陈代光教授是我国一位著名历史地理学者.文章主要论述其在岭南广州、港澳、雷州等城市、南海海上丝绸之路交通、区域历史地理、广东历史地图集编纂、地名、中国历史地理教材建设、历史地理人才培养,以及历史地理为社会经济发展服务等方面的学术成就和重要贡献,以作为对陈代光教授的一种纪念,同时唤起社会各界对这门又古又今、既要看书、又要走路的学科的关注.  相似文献   

吐哈盆地航测数据库管理系统   总被引：1，自引：0，他引：1  

郑贵洲  王欣  曹泽欣  郑卫勤 《物探化探计算技术》2002,24(4):345-348

随着吐哈盆地航测不断深入，航测数据急剧增加，航测成果管理已进入信息化阶段，吐哈盆地航测数据库管理系统是基于Visual C^ 、ODBC 、DAO、ActiveX、COM等技术开发的属性数据管理系统，系统实现了对吐哈盆地航测成果数据的动态存储和管理，可完成属性数据输入，航测数据建库，航测数据更新，数据记录修改，属性结构修改，数据查询检索等功能。  相似文献   

基于分形理论的航空图像分类方法   总被引：2，自引：0，他引：2  

李厚强  刘政凯  林峰 《遥感学报》2001,5(4):353-357

提出一种基于分形理论和BP神经网络的航空遥感图像有监督分类方法。该方法尝试将航空图像的光谱信息和纹理特征相结合。它首先将彩色航空图像由RGB格式转化为HSI格式，然后，根据亮度计算分数维、多重分形广义维数谱q-D(q)和“空隙”等基于分形的纹理特征，同时加入归一化的色度和饱和度作为光谱特征，采用BP神经网络作为分类器。通过对彩色航空图像的分类实验，结果证实该方法行之有效。  相似文献   

基于二面投影原理的单张像片的连续制图     

任留成  谭建成等 《测绘学院学报》2001,18(1):67-68

考虑利用卫星像片进行制图问题，对于需要两张或更多张卫片才能覆盖的地区进行连续制图时，需要研究多张卫片的图像镶嵌问题，利用二面投影原理对卫片原的镶嵌问题进行了研究，主要考虑两张相邻卫片的几何配准问题。  相似文献   

洞庭湖区第四纪气候变化的初步探讨   总被引：14，自引：0，他引：14  

张人权  梁杏  张国梁  皮建高 《地质科技情报》2001,20(2):1-5

探讨了洞庭湖区第四纪以来的气候变化，初步得出以下规律：更新世气候变化剧烈，气候组合暖湿（温湿）与冷干；全新世气候转为温凉，主要气候组合为温湿与凉干；历史时期气候主要仍温湿与凉干交替，但15 世纪以来出现短暂的温干与凉温期；15世纪以来，气候波动频繁，有愈来愈不稳定的趋向，进入20世纪，旱涝灾害更加。在全球变暖的背景下，预计该区未来气候趋向于暖湿，但不排除暖干的可能性。  相似文献