The Statistical Analysis of Migration of Strong Earthquakes─Taking the North China Region as an Example

INTRODUCTIONMigrationofstrongearthquakesisaphenomenonwherebystrongearthquakestakeplaceinsuccessionincertainspatiallyregularpatterns (ZhangGuomin ,etal,2 0 0 1 ) .Seismologistsintheworldhavenoticedthisphenomenonforalongtime .Manyinstanceswerediscoveredinthepastdecades ,suchasthemigrationofstrongearthquakesalongtheNorthAnatolianFaultinTurkeysince1 939(Richter,1 958)andthemigrationofaseriesofearthquakes (MS ≥ 6 0 )aftertheMS7 9earthquakeinKwandong ,Japan (Utsu ,1 987) .Theexamplesofre…     

多源异构土地利用数据的建库方案探讨

随着国土资源信息化建设的快速发展,各地积累了大量的土地利用数据及其变更数据,对这些海量数据的管理和使用,使得多源异构土地利用数据的集成成为当务之急。本文结合建库工作实际,简要介绍了多源异构土地利用数据存在的问题、整合建库的技术方案以及质量控制方案。     

一次飑线型的多普勒雷达资料特征分析

此次飑线型弓形回波发生在高空前倾槽天气形势下,低层浅薄的水汽辐合及高空中等强度垂直切变为飑线发生发展提供了有利条件。飑线弓形回波北端具有明显的气旋性特征,飑线型弓形回波由许多小弓形回波组成,在弓形回波后部有后侧入流急流存在,弓形回波顶点中空有明显的涡旋式辐合,与弓形回波顶点相对应地面出现灾害性大风和小冰雹。飑线型弓形回波受高空WNW偏移引导气流右侧30°移动,平均移速60km/h。将2部雷达资料相结合,可以提前1h发布强对流天气预警。     

1996年11月9日长江口外6.1级地震影响场与震中区地震地质概述

1996年11月9日长江口外6.1级地震震中位于北纬31°43’,东经123°04’震级(Ms)6.1级,震源深度7km,陆上最大地震烈度为4度。上海虽普遍有感,但无明显损失。在解译长江口外地球物理场异常的基础上,发现这次地震发生在东西向崇明—启东断裂与北东向镇海断裂的交汇部位,是北东向断裂右旋滑移的结果。     

西宁台DD－1地震记录仪的改造

介绍了西宁台ＤＤ－１地震仪的改造工作，并讨论了改造后的ＤＤ－１记录器的工作状况，得出：改造后的ＤＤ－１地震记录器基本上解决了原记录器的缺点，使记录性能及记录效果有了明显的提高，其改造工作是成功的。     

脊髓纵裂征一例

本文报道了一例脊髓纵裂征，并着重讨论了该病Ｘ线ＣＴ表现，其中脊髓中央的骨嵴是诊断该病的关键，通过Ｘ线ＣＴ检查对比认为ＣＴ是最理想的诊断依据     

福建省地层多重划分,对比研究（续）

福建省地层多重划分、对比研究（续）李兼海，王国平，郑铁藩，梁诗经（福建省区域地质调查队，三明，３６５００１）３晚三叠世一新第三纪印支运动后，福建地壳发生了重大变革，全境由海转变成陆地。晚三叠世一中佛罗世，除闽西南局部地区有海湾泻湖相沉积外，皆为河流一...     

γ能谱法和X-荧光法在新疆阔尔真阔腊金矿预测中的应用

使用伽玛能谱法和X—荧光法组合在残积土发育的新疆阔尔真阔腊金矿床找矿预测中的应用实践表明，这两种方法组合是一种简便、快速、有效的间接找金方法。不同类型的蚀变带，具有不同的伽玛能谱和X—荧光特征。二者的结合使用能有效地区分不同类型的热液蚀变带，同时为在阉尔真阔腊金矿区及外围进行金矿体的定位预测提供了十分有意义的资料。     

A long connection (750–380 Ma) between South China and Australia: paleomagnetic constraints

A new paleomagnetic study has been carried out on sediments of middle Cambrian age in the North Sichuan Basin (Yangtze Block). Detailed stepwise thermal demagnetizations allowed us to isolate three components. Site-mean direction derived from higher temperature components is D/I=146.9°/–17.1° (₉₅=8.3°) yielding a pole position at 51.3°S, 166.0°E. The fold and reversal tests suggest that remanence was acquired during early stage of sedimentation. Combined with the high-qualities early Sinian (748 Ma) and middle Silurian poles obtained recently from the Yangtze block, the deriving polar track demonstrates a similar loop to that of Australia. After rotating these poles from South China to fit that of Australia, the South China Block is placed against northwestern Australia. This reconstruction favors the correlations of the Jiangnan Grenville-age orogenic belt with the Rudall belt of western Australia, and subsequently the late Proterozoic Jiangnan and Officer/Adelaide rift systems. The paleobiogeographic evidence also indicates that this configuration might maintain by the middle Devonian.     

In situ zircon Hf isotopic, U-Pb age and trace element study of monzonite xenoliths from Pingquan and Fuxin basalts:Tracking the thermal events of 169 Ma and 107 Ma in Yanliao area

K-Ar ages of the Mesozoic (92-100 Ma) Fuxin alkalic basalts (western Liaoning Province) and the Tertiary (23-45 Ma) Pingquan alkalic basalts (eastern Hebei Province), and the results of in situ zircon U-Pb dating, Hf isotope and the trace elements from three monzonite xenoliths carried in the alkalic basalts are reported. The crust-mantle interaction occurring in the Yanshan intracontinental orogenic belt is also discussed. Fuxin zircons show highly uniform U-Pb age ((169±3) Ma). More than 95% Pingquan zircons display the age of (107±10) Ma except two are 2491 Ma and 513 Ma respectively. Zircons with the ages of (169±3) Ma have εHf close to zero. εHf of the zircons with the ages of (107±10) Ma are mainly at -11.5--16.3, showing the crustal derivation. Fuxin zircons contain low Nb, Ta, Sr, Th, U contents, low and narrow Hf model ages (0.87-1.00 Ga), which reflect that the source materials of the monzonite xenoliths are young to Pingquan (focus at (1.28±0.08) Ga). High contents of the incompatible elements, and wide range of Hf model ages (0.89-2.56 Ga) in Pingquan zircons suggest a more complex source and the highly crustal maturity in their petrogenesis. Comprehensive information including the published data indicates that J3-K1 is the key period of the deep processes and shallow tectonic reverse in the Yanliao area. However, the processes were highly heterogeneous in spatial and in temporal.