Research on the Effects of the Contents of Radioactive Elements on Granularity and Climate Change： An Example of SZK1 and SZK2 Drill Holes Strata in the Fuzhou Basin

INTRODUCTIONFuzhou basin is a faulted basin developed during the mid-late Quaternary,filled with marine ,terrestrial and alternating marine-terrestrial facies sediments (Lin,1979 ;Lan,et al .,1986 ; Han,etal .,1992 ;Ding,et al .,1992 ; Wang,et al .,2000 ; Wang,et al .,2002) .Inthe basin,concealedfaults are distributed. With the support of a project entitled“Testing exploration of active fault inurban area”of the National Development and ReformCommission,two drill holes (SZK1 and S…     

Average slip rate,earthquake rupturing segmentation and recurrence behavior on the Litang fault zone,western Sichuan Province,China

The Litang fault zone (LFZ) is an important active fault within the northwestern Sichuan sub-block. To-gether with the Garzê-Yushu, Xianshuihe, and An-ninghe fault zones on its northern, eastern and south-eastern sides, the LFZ constitutes the lateral extrusion tectonic system in the southeastern part of the Qing-hai-Tibetan Plateau[1,2] (Fig. 1). According to instru-mental records, historical recordings and field investi- gation, an earthquake (Ms7.3) occurred on its middle to south se…     

永定河上游晚更新世晚期以来的堆积阶地年代测定

应用1 4 C测年法和热释光方法对采自永定河上游晚更新世晚期以来形成的堆积阶地样品进行了年代测定。研究结果表明 ,永定河上游三条一级支流的低阶地形成时代具有一定的同时性 ,第三级阶地的下切时间大约在 30 0 0 0aB .P .;第二级阶地的下切时间大约在 10 0 0 0aB .P .;第一级阶地的下切时间大约在 4 0 0 0aB .P .。气候变暖对第二级阶地形成起主导作用 ,构造作用对最新阶地形成有一定的影响     

2009.3.23东京成田机场坠机的气象条件分析与数值模拟

2009年3月23日美国联邦快递公司的一架飞机在东京成田机场坠毁,事故发生的原因与当时的气象条件密切相关。利用美国新一代非静力平衡中尺度数值预报模式(WRF V2.2)对该次过程进行数值模拟,着重分析事故发生前后各种物理量的水平分布和垂直配置,并诊断分析了该时段内位温平流的分布特征。结果表明,强风发生在位温平流梯度区。强冷空气影响下形成的低空水平风的垂直切变、低层强下沉速度引起的侧风切变和地面强风是造成此次事故的主要气象原因。     

福州市活断层探测与地震危险性评价

大量震例研究表明，活动断层产生的直下型地震对城市的破坏非常严重，应用先进有效的地质与地球物理探测技术，准确地探明城市之下及附近活动断层分布，确定直下型地震的震源和危害性是我国城市减灾工作面临的一个非常急迫的实际问题。《福州市活断层探测与地震危险性评价》项目作为中国地震局全国城市活动断层探测的试点与示范项目于2001年初开始实施，2004年8月通过中国地震局的验收。项目围绕解决城市范围内的断裂定位、定年、定性、深部背景、地震危险性和危害性及防震减灾对策等一系列科学问题，通过“初查与目标区主要活断层鉴定”、“深部地震构造环境探测”、“地震活断层鉴定与危险性评价”、“地震活断层的详细探测”、“地震活断层危害性评价”和“活断层地理信息系统建设”等阶段的探测和评价工作，同时在福州市城、郊区全面开展壤中气汞、土壤汞、气氡、地质雷达、多道直流电法、瞬变电磁法、浅层地震折射法、浅层地震反射法、勘探震源效果对比、用于建立福州盆地埋藏第四系(标准)剖面的钻探等多种手段的试验探测，总结各种试验探测的技术指标和实践经验，在活断层的综合试验探测、定位定年、地震危险性和危害性评价等方面取得了下列成果与结论：(1)福州市活断层综合试验探测成果表明，在充分收集、整理与分析相关地质、地球物理、钻孔等资料的基础上，以地球化学探测为先导“侦察机”，确定了活断层的可能位置；以浅层地震勘探为主要探测方法，辅以电磁勘探作为补充，并利用钻探建立的第四系(标准)剖面或地层层序及测井获得的各种地球物理参数进行必要的校正和验证，结合裸露地表断层或埋深较浅断层的槽探及古地震调查或隐伏断层两侧钻孔岩芯岩性、层序、绝对年龄或孢粉等相对年龄的测定与对比等，是进行城市活断层探测(定位)与地震危险性、危害性评价(定年、定性)的最佳组合方法。(2)福州盆地位于具有发生中等强度地震的区域地震构造环境中，“台湾动力触角”对其影响相对较弱。(3)福州盆地主要断裂的活动性较弱，经鉴定的6条目标断裂都不是全新世断裂。其中，八一水库-尚干断裂和闽侯-南屿断裂至少为晚更新世中期以来的不活动断裂，其它为晚更新世以来不活动断裂。(4)福州盆地深部不存在发生直下型强烈破坏性地震的构造环境，其邻近的长乐-诏安断裂带是未来可能会发生对福州市有影响的地震震源区。(5)福州盆地主要断裂存在发生中等-中强地震的危险性，但发震概率较小。(6)福州盆地地震危害性较弱，地面发生地震地表破裂带的可能性不大。(7)开发建立了全国第一个活断层地理信息系统，具备信息查询显示、数据管理、数据的分析处理和咨询服务等功能。     

Terraces and Tectonic Uplifts at Yandantu and Changcaogou on the Northern Margin Fault of Altun

The formation of strath and strath terrace is closely related to tectonic uplift in the drainage basin. Based on the investigation of straths at Yandantu and Changcaogou on the eastern segment of the northern margin fault of Altun, and in combination with the paleoclimatic data,the tectonic uplift since late Epipleistocene as revealed by stream terraces at the two places is discussed. At Yandantu, three levels of stream terraces( T1, T2 and T3 )have developed since 16ka BP, where T1, T3 and T2 are fill terraces and the buried major straths are exposed. The ages of three treads are dated to be about 16.1ka BP, 12 .Ska BP and 6.2ka BP, respectively. The three terraces reflect three tectonic uplift events, while the ages of the treads represent the occurrence time of these events. The stream is still beveling the bedrock and widening the channel at present, and the modern strath is being generated. The uplift rate is 4.8～4.5mm/a since 16.1 ka BP in this area. From 12.8ka B .P to 6.2ka BP, The uplift rate was 6.4mm/a.The uplift rate is 3. lmm/a since 6.2ka BP.At Changcaogou, four levels Of stream terraces(T1, T2, T3 and T1)have developed since 7ka BP. All of them are fill terraces. There are buried straths under the deposits. The buried major strath is exposed on T3 and T2 and the minor strath on T1‘and T1. The ages of treads of the three terraces (T3, T2 and T1’) are 7 ka BP, 3 ka BP and 2.5 ka BP, respectively. The four terraces reflect two uplift events induced by tectonic activities. One occurred in about 7 ka BP, and the other in 3ka BP. The uplift rate is 5.gmm/a since 7.0 ka BP at Changcaogou.From 7ka BP to 3ka BP, the uplift rate was 7.0mm/a, and since 3ka BP till now, the uplift rate is 4.7 mm/a.     

Pattern of latest tectonic motion and its dynamics for active blocks in Sichuan-Yunnan region,China

Based on the concept of “active blocks” and spatial distribution of historical earthquakes with surface ruptures as well as major and subordinate active faults. The Sichuan-Yunnan region can be divided into four first-order blocks. They are the Markam block (I), the Sichuan-Yunnan rhombic block (II), Baoshan-Pu’er block (III), and Mizhina-Ximeng block (IV). Cut by sub-ordinate NE-trending active faults, the Sichuan-Yunnan rhombic block (II) can be further divided into two sub-blocks: the northwestern Sichuan sub-block (ll₁) and the middle Yunnan sub-block (ll₂), while the Baoshan- Pu’er block (III) can be further divided into three sub-blocks: Baoshan sub-block (Ill₁), Jinggu sub-block (lll₂), and Mengla sub-block (lll₃). A quantitative study of offset landforms is carried out and the basic types of active faults and their long-term slip rates along the major boundaries of active blocks of different orders in the Sichuan-Yunnan region are determined, through slip vector analysis, the motion states of the active blocks are clarified and the deformation coordination on the block margins is discussed. It is suggested that the tectonic motion of the blocks in this region is a complex or superimposition of three basic types of motions: southeastward sliding, ro-tating on vertical axis, and uplifting. The Markam block (I), the northwestern Sichuan sub-block (ll₁), and middle Yunnan sub-block (ll₂) have a southeastward horizontal sliding rate of 1-5 mm/a, clockwise rotating angular rate of 1.4-4°/Ma, and uplifting rate of about 1 mm/a. The Baoshan-Pu’er (III) and Mizhina-Ximeng (IV) blocks have also been extensively clockwise rotated. This pattern of motion is a strain response to the collision between the Indian and Eurasian plates and the localized deformation and differential slip on the block margins associated with the northward motion of the Indian Plate. Because a set of transverse thrusts between the blocks absorbs and transforms some components of eastward or southeastward sliding motion, the eastward escape or extrusion of the Tibetan Plateau is limited as “imbricated thrusting transformation-limited extrusion model”.

     

东昆仑断裂带中东部地震破裂分段性与走滑运动分解作用

基于卫星影像解译和野外考察测量,本文对东昆仑断裂带中东部的3条次级断裂(托索湖断裂、玛沁断裂和玛曲断裂)的滑动速率以及全新世以来的古地震活动特征进行了分析研究。托索湖段与玛沁段走向产生20°和30°的双挤压弯曲,形成阿尼玛卿山挤压隆起,作为托索湖段和玛沁段的破裂分段标志,成为1937年托索湖7.5级地震地表破裂带的终止点;在西贡周西侧和莫哈塘南侧,阿万仓断裂以40°的夹角与东昆仑断裂带相交,形成西贡周断裂交汇区,成为玛沁段与玛曲段破裂分段的标志。通过构造地貌方法获得西段托索湖断裂晚第四纪晚期以来的平均水平速率为10.8±1mm/a,垂直滑动速率为1.2±0.2mm/a;中段玛沁断裂带晚第四纪晚期以来的平均水平滑动速率为9.3±2mm/a,垂直滑动速率为0.7±0.1mm/a;西贡周断层交汇区平均水平滑动速率为7.4±1mm/a,垂直滑动速率为1.2±0.1mm/a;东段玛曲断裂晚第四纪晚期以来的平均水平滑动速率为4.9±1.3mm/a,垂直滑动速率为0.3mm/a。断裂的滑动速率从西至东呈梯度下降,通过构造转换矢量分解获得阿万仓断裂西支的左旋水平走滑速率为2.4mm/a,东支的左旋水平走滑速率为1.4mm/a,垂直断裂的水平缩短速率为2.3mm/a,阿万仓断裂带西支和东支构成一个滑动分解模式。3条次级断裂的活动均产生独立地表破裂,西侧的托索湖断裂发生了1937年MS7.5级地震,中段玛沁断裂发生了公元1061年格萨尔王时期和距今358~430CalaBP的地表破裂,玛曲段地表破裂距今约1055~1524aBP,显示出段落之间应力触发有关的地震破裂事件沿断裂带单向迁移的特征。同时利用断裂单次地震位移和古地震复发周期获得断裂的长期滑动速率,结果显示与构造地貌方法获得的滑动速率几乎一致,也显示自西向东逐渐递减的趋势。断裂滑动速率的递减与几何结构走向的弯曲以及横向断裂的相交一一对应,东昆仑断裂带的滑动速率梯度递减的主要原因是东昆仑断裂带东延和横向断裂相交,构造转换造成的。     

长白山天池火山近代喷发物的热释光（TL）年代学初步研究

利用热释光（TL）技术首次测定了长白山天池火山近代喷发浮岩的年 代。测定结果在误差范围内与历史记载及其它测年方法的结果吻合,表明天池火山在最近2000 a来,至少发生了两次碱流质浮岩的喷发,同时也表明用TL方法能比较可靠地测定火山喷发物的年代,为近代火山喷发历史的恢复提供年代学依据。     

基于人工神经网络的GMS云图四类云系的识别

应用人工神经网络方法较成功地识别了GMS云图中的四类云系,并与传统的统计识别方法进行了对比,得出结论:神经网络方法更适合于云系的特征识别。还研究了神经网络本身的问题,取得一些网络设计的经验。