Deep electrical anomaly in the M7.5 Qiongzhou earthquake region and its relation with future seismicity

From the magnetotelluric detection in the epicentral region and the adjacent areas of the 1605 M7.5 Qiongzhou earthquake, we have discovered there is a low resistive body in the deep crust of the epicentral region. The low resistive body extends straightly from the depth of about 13 km to the upper mantle, which is supposed as an up-rising mantle pole. We therefore consider it is just the existing mantle pole and its upwelling thermal material that result in the faulting and stick-slipping activities of the upper crust, which is an important factor for the M7.5 Qiongzhou great earthquake occurrence. The postseismic faulting activity is characterized by creep, which shows that the risk is greatly decreased for the occurrence of a great earthquake with similar intensity in the future.     

Distribution of lipids in modern soils from various regions with continuous climate (moisture-heat) change in China and their climate significance

Total 26 modern soil samples were collected from various regions under different climate conditions from tropical to arid temperate in China and systematically analyzed for their organic matters by GC/MS in order to evaluate climatic impacts on soil organic components. Abundant lipids molecules were recognized, including n-alkanes, n-alkenones, and long-chain branched alkanes. We find the predominance of main peaks of long-chain n-alkanes (nC29,nC31,nC33) and short-chain ones(nC16,nC17,nC18) records information of soil generation in warm-humid and cold-dry regions. The proportion of n-alkanes(nC16 nC17 nC18)to(nC29 nC31 nC33)varies in good agreement with moisture-heat conditions and thus probably can serve as a new index for climate change. The ratios of C21-/nC22 ,nC17/nC31 and (nC15 nC17 nC19)/(nC27 nC29 nC31)of n-alkanes, indicating respectively input ratios of lower bacterial alga, aquatic organisms, and higher plants and terraneous organisms, co-vary well in different climate regions from forest to grassland and desert, suggesting that they have also reflected the difference of climates between monsoon region and inland one. The C21-/C22 ratio of n-alkan-2-one records largely the discrepancy of temperature from north to south of China bordered by the Qinling Mountains, but less humidity. The C21-/C22 ratio of n-alkan-3-ones changes well with climatic factors, such as temperature and humidity. The biogenic source of series A-D long-chain branched alkanes may be derived from some kinds of special epiphyte that most likely live in weak oxic-anoxic and moisture-heat environments, suggesting their distribution record as well some information on climatic change. All these researches demonstrate that the distributions of lipids molecules in modern soils in China record well signals of climates from quite different climatic regions, and can serve as important climatic proxies to reveal climatic change over China.     

The crustal structure under Sanjiang and its dynamic implications: Revealed by seismic reflection/refraction profile between Zhefang and Binchuan,Yunnan

The Sanjiang area in southwest China is considered as a tectonic intersection belt between the Tethys-Alps and the western Pacific, and has endured three-phase evolution processes: Proto-Tethys,Paleo-Tethys and Meso-Tethys[1―4]. In this area, its tectonics and struc- ture are extremely complicated, and intensively extru-sive deformation and faults are widely developed[1―3]. For that, the area is considered as the ideal na- ture-laboratory to study the evolution of Paleo-Tethys and also …     

Land cover changes based on plant successions: Deforestation,rehabilitation and degeneration of forest in the upper Dadu River watershed

The land use/cover classification system is the foundation for land use/cover change study. Remote sensing data were firstly used for land use and land cover classification in the United States in 1971 and the Anderson Classification System was proposed in 1976[1], which was put into use in mapping 1:250000 land use and land cover of the United States. A series of new land cover classification systems have been established in recent years through research projects such as FAO LCCS and Bi…     

新疆伽师强震群震源应力环境分析

本文基于能量辐射系数（Ag)和环境剪应力（τ0）讨论了伽师强震群发生的应力环境背景。1988年以来11年的环境剪应力τ0值表明,伽师震群发生在相对低的应力环境下,1992年以来8年的能量辐射系数Ag值显示震源区介质强度较弱,震中位于介质性质发生变化的过渡区。同时,震源区（喀什）能量辐射系数Ag自1994年5月起系统性地降低,较好地显示了1996年3月19日至1998年8月27日期间震源区发生的10次强震前（包括1996年3月19日阿图什6．9级地震）震源区介质性质的前兆性异常变化,本文由此对伽师强震群的成因进行了讨论。     

1998年夏季松花江、嫩江流域大暴雨中尺度雨团活动分析

用地面逐时降水资料、静止卫星云图、雷达图及常规气象资料,分析了８月上旬不同时段松花江及嫩江流域出现的中尺度雨团（≥５．０ｍｍ／ｈ）活动情况。根据它们的活动特点及在卫生云图、雷达回波上的演变和物理量诊断场的特征,将其分为两类。第１类是典型的冷涡中尺度雨团,第２类为东南方有地面气旋活动的冷涡中尺度雨团,它们都出现在冷涡的成熟及消亡阶段,活动在冷涡的不同部位,有着各自不同的演变特点。由此构建了相应的中尺     

泡塑-地电联用法找金研究

本文介绍了一种新的找金方法－泡塑－地电联用法。该用法将泡沫塑料吸附和地电化学离子提取等两种找金方法融为一体。通过综合研究联用法找金机理,改进提取器材料、结构及仪器设备,并结合研究金的地坏化学规律,使该联用法成为寻找隐伏型金矿的新方法。该联用法既发挥了上述两种方法的优点,又克服了二者的缺点,具有灵敏度高、探测深度大和使用安全可靠的特点。     

小热泉子铜矿床物化探找矿效果及综合找矿模式

对小热泉子铜矿进行了一系列物探找矿方法的试验研究工作,其中包括：重力、井中充电激发极化法、高精度磁测、地－井方式激发极化法、甚低频电磁法、瞬变电磁法、天然电磁场测深、可控源音频电磁法、分布式被动源陈列电磁法及中间梯度激发极化法等。仅钻孔原生晕取得一定的地质效果。     

松花江、嫩江流域降水异常对水位变化的影响

利用松花法、嫩江流域的气象和水文资料,讨论了该流域降水对水位变化的影响。结论指出,松花江、嫩江流域汛期一变化与流域内的降水有密切的关系。１９９８年夏季特大洪水主要是由嫩江流域降水异常偏多引起的,逐日水位变化取决于上游水位和临近流域的降水情况。     

1998年夏季松花江、嫩江流域大暴雨的水汽输送

使用松花江、嫩江流域内 94个地面气象观测站 1 998年 6～ 8月逐日降水资料和同期的 NCEP/NCAR再分析资料 ,分析了造成 1 998年夏季中国东北地区松花江、嫩江流域出现超历史纪录特大洪水大暴雨过程时的水汽输送。分析结果认为 ,关键在于南部充沛的水汽向高纬度地区的经向输送。水汽的源地可以追朔到相当远 ,主要来自西太平洋副热带高压南部低纬热带地区和印度洋洋面。制约水汽输送的条件主要是西太平洋副热带高压南北位置、低空偏南急流强弱等。