2017年8月9日精河6.6级地震序列重定位与发震构造初步研究     

刘建明  高荣  王琼  聂晓红 《中国地震》2017,33(4):663-670

基于新疆区域数字地震台网震相观测报告，采用HypoDD方法精确定位了精河M_S6.6地震序列M_L≥1.0地震的震源位置，综合分析了此次地震序列的空间分布特征和可能的发震构造。结果显示，主震震中为44.2639°N、82.8294°E，震源初始破裂深度为17.6km；地震序列总体沿近EW（273°）向单侧扩展，展布长度约20km；震源深度优势分布范围为7～17km；沿余震走向的深度剖面显示，主震向西10km范围内，余震震源有逐渐变浅的趋势，余震序列中尾端向SW方向偏转的地震震源较深；垂直于地震序列的深度剖面显示，地震序列自北向南呈现逐渐加深的变化特征，表明发震断层面倾向为S倾。综合考虑中国地震局地球物理研究所给定的震源机制解以及震源区地质构造情况推测，精河M_S6.6地震发震构造可能为库松木契克山前断裂东段。  相似文献   

Two types of summertime heating over Asian large-scale orography and excitation of potential-vorticity forcing II. Sensible heating over Tibetan-Iranian Plateau     

YiMin Liu  ZiQian Wang  HaiFeng Zhuo  GuoXiong Wu 《中国科学:地球科学(英文版)》2017,60(4):733-744

Based on analysis and simulation, the interaction of thermal forcing between the Tibetan Plateau (TP) and Iranian Plateau (IP) in summer is investigated. Associated influences on water vapor transport in the Asian subtropical monsoon region and the formation of a cold center in the lower stratosphere over Eurasia are also investigated. Results show that surface sensible heating (SH) over the two plateaus not only have mutual influences but also feedback to each other. SH over the IP can reduce the SH and increase the LH over the TP, whereas the SH over the TP can increase surface heating over the IP, thereby reaching quasi-equilibrium among the SH and LH over the TP, IP SH and atmosphere vertical motion. Therefore, the so-called Tibetan-Iranian Plateau coupling system (TIPS) is constructed, which influences atmosphere circulation. In the TIPS system, interaction between surface SH and LH over the TP plays a leading role. SH of the IP and TP influences on other regions not only have superimposed effects but also mutually offset. Accounting for contributions to the convergence of water vapor transport in the Asian subtropical monsoon region, TP SH contributes more than twice that of the IP. The combined influence of SH over TP and IP represents the major contribution to the convergence of water vapor transport in that region. In addition, the heating effect of TIPS increases the upper tropospheric temperature maximum and lifts the tropopause, cooling the lower stratosphere. Combined with large-scale thermal forcing of the Eurasian continent, the TIPS produces a strong anticyclonic circulation and the South Asian High that warms the upper troposphere and cools the lower stratosphere, thereby affecting regional and global weather and climate.  相似文献   

苏06井不同深度水温变化特征     

陈健  仇中阳  刘江斌  李松华  李子威  杨彦兵 《地震地磁观测与研究》2017,38(6):64-71

根据2008—2016年苏06井400 m和800 m深度的水温观测数据,分析不同深度的水温年变速率及日变曲线形态,并运用差值、水温梯度的小波变换方法,对2个不同深度的水温变化特征进行分析,发现:苏06井不同深度水温的长期变化与水位变化具有一定同步性,事实上水位变化起主导作用,构造引起水位变化使不同深度水温的表现不同,对周围近距离显著地震发生有一定意义;从短期变化看,不同深度水温之间很少出现同步变化;400 m深度水温异常信号频度及强度高于800 m深度水温异常信号。  相似文献   

Extended finite element framework for fault rupture dynamics including bulk plasticity     

Fushen Liu  Ronaldo I. Borja 《国际地质力学数值与分析法杂志》2013,37(18):3087-3111

We present an explicit extended finite element framework for fault rupture dynamics accommodating bulk plasticity near the fault. The technique is more robust than the standard split‐node method because it can accommodate a fault propagating freely through the interior of finite elements. To fully exploit the explicit algorithmic framework, we perform mass lumping on the enriched finite elements that preserve the kinetic energy of the rigid body and enrichment modes. We show that with this technique, the extended FE solution reproduces the standard split‐node solution, but with the added advantage that it can also accommodate randomly propagating faults. We use different elastoplastic constitutive models appropriate for geomaterials, including the Mohr–Coulomb, Drucker–Prager, modified Cam‐Clay, and a conical plasticity model with a compression cap, to capture off‐fault bulk plasticity. More specifically, the cap model adds robustness to the framework because it can accommodate various modes of deformation, including compaction, dilatation, and shearing. Copyright © 2013 John Wiley & Sons, Ltd.  相似文献   

Optical dating of sand wedges and ice‐wedge casts from Qinghai Lake area on the northeastern Qinghai‐Tibetan Plateau and its palaeoenvironmental implications     

Xiang‐Jun Liu  Zhong‐Ping Lai 《Boreas: An International Journal of Quaternary Research》2013,42(2):333-341

Sand wedges and ice‐wedge casts in the Qinghai Lake area on the northeastern Qinghai‐Tibetan Plateau (QTP) occur within alluvial gravel or river terrace deposits. In this study, we report the results of quartz Optically Stimulated Luminescence (OSL) dating of the infill of five relict sand wedges and one ice‐wedge cast. Combining our dating results with previously published luminescence ages of permafrost wedges in the Qinghai Lake area, we show that sand/ice wedges formed at c. 62 ka, c. 45 ka and between 30 and 15 ka, and that the mean annual air temperature (MAAT) was depressed by at least ～3°C relative to present during the sand/ice‐wedge formation periods. This new work is partially corroborated by post‐LGM proxy records from lakes and aeolian deposits reported from the northeastern QTP. It also significantly extends the palaeoenvironmental record in the region in the period before the LGM, when other proxy records are rare, allowing a better understanding of the palaeoenvironmental conditions on the northeastern QTP.  相似文献   

Wave attenuation in the marginal ice zone during LIMEX     

Antony K. Liu  Paris W. Vachon  Chin Y. Peng  A.S. Bhogal 《大气与海洋》2013,51(2):192-206

Abstract

During the Labrador Ice Margin Experiments, LIMEX ‘87 in March 1987 and LIMEX ‘89 in March and April 1989, the Canada Centre for Remote Sensing (CCRS) CV‐580 aircraft collected synthetic aperture radar (SAR) image data over the marginal ice zone off the east coast of Newfoundland, Canada. One aspect of these experimental programs was the observation of ocean waves penetrating into the marginal ice zone (MIZ). Based upon directional wavenumber spectra derived from SAR image data, the wave attenuation rate is estimated using SAR image spectra and compared with predictions from a model developed by Liu and Mollo‐Christensen (1988). The wave and ice conditions were considerably different in LIMEX ‘87 and LIMEX ‘89. However, the model‐data comparisons are very good for all ice conditions observed. Both the model and the SAR‐derived wave attenuation rates show a characteristic roll‐over at high wavenumbers. A model for the eddy viscosity is proposed, using dimensional analysis, as a simple function of ice roughness and wave‐induced velocity. Eddy viscosities derived from SAR and wave buoy data for the wave attenuation rate show a trend that is consistent with the proposed model.  相似文献   

Development and application of a catchment scale diffuse nitrate modelling tool     

Shuming Liu  Peter Tucker  Martin Mansell  Andrew Hursthouse 《水文研究》2005,19(13):2625-2639

Water pollution from diffuse sources is a problem of increasing concern. Efforts to control diffuse pollution have been confined mainly to agricultural land and forests. Little attention has been paid to sources of diffuse pollution from urban areas. A diffuse nitrate modelling tool (DNMT) has been developed for modelling the fate of nitrate in urban areas. This tool works at the catchment scale and has a modular structure that consists of three components: the hydrological module, the nitrogen cycle module and the nitrate transport module. The hydrological model describes the possible flow pathways. The nitrogen cycle model accounts for the mass balance of nitrate and calculates the amount of nitrate for potential loss. The nitrate transport module simulates the movement of nitrate within and from the soil to the receiving water. This paper demonstrates the development of the tool and its application in the White Cart Water catchment. This implementation of the tool shows that it has a good capability for simulating the fate of nitrate in urban catchments. Copyright © 2005 John Wiley & Sons, Ltd.  相似文献   

Key Groundwater Control Factors of Deep Buried Coalfield by Landform and Sedimentation in the Northern Ordos Basin     

Jian Yang  Ji Liu  Hao Huang  Xiangyang Liang 《地球科学进展》2019,34(5):523-530

There were three landforms (i.e. desert, bedrock platform and loess gully) in deep-buried coalfield of northern Ordos Basin. Water inflow of working face in desert area was 1~2 orders of magnitude larger than that in other landform areas. In order to find out the key controlling factors of the directly water filled aquifers on the roof of the coal seam, we carried out research from the aspects of topography, landform and geological sedimentation. The results showed that desert landform provides abundant recharge water for underlying aquifers because of gentle topography, large precipitation infiltration coefficient, thick and water-rich quaternary system. While bedrock platform and loess gully landform were the water sources with weak recharge capacity of underlying aquifers. The sandstone-mudstone interbedding structure formed by continental deposits resulted in the absence of regional stable aquifers in Jurassic and Cretaceous strata on the roof of coal seams. Pumping tests of boreholes showed that all strata belong to weak to medium water-rich aquifers. The groundwater level of Cretaceous aquifer decreased by 20~130 m in three mines. There was a close hydraulic relationship between shallow and deep aquifers. The Mesozoic strata belonged to fluvial deposits. Qilizhen sandstone and Zhenwudong sandstone aquifers were mainly developed on the roof of the coal seam, which were characterized by thick medium-coarse sandstone sections. The geological and sedimentary conditions of direct water-filled aquifer were similar, but the amount of borehole water, cumulative pre-drainage water and water inflow from goaf in desert geomorphic area were much larger than those in bedrock platform and loess gully geomorphic area. The water-rich of the aquifer was mainly controlled by geomorphology, and the water sources of the deep aquifers were meteoric precipitation and Quaternary aquifer. In different mines with similar Quaternary conditions in Mu Us Desert, there were also great differences in the amount of borehole water, cumulative pre-drainage water and water inflow from goafs. The difference was related to the thickness and lithology of the aquifers. It reflected that the geological sedimentary conditions of the coal seam roof were also important factors to control the water-rich of the aquifers. Topography, landform and geological sedimentation were the key factors to control the water-rich of the aquifer directly and the water inflow from the working face.  相似文献   

Advances in Glycerol Dialkyl Glycerol Tetraethers and Long-Chain Alkyl Diols in the Marine Sediments: Implications for Paleoclimatic and Paleoenvironmental Changes     

Lilei Chen  Feng Li  Jian Liu 《地球科学进展》2019,34(8):855-867

Lipid biomarkers widely dotted in marine sediments, as their distribution characteristics accurately record huge information on the metabolism of the original organisms and migration and transformation of these organic components, are often used to reconstruct the paleoclimatic and paleoenvironmental conditions. This paper reviewed the progress in the study of paleoclimatic-environmental changes during the late Quaternary using abundant core lipids Glycerol Dialkyl Glyceryl Tetraethers (GDGTs) and long-chain alkyl diols in marginal sea sediments. It is pointed out that clarifying the “source-sink” process of lipid biomarkers buried in marine sediments is a prerequisite for paleoclimatic-environmental reconstruction. It is believed that the use of multiple indicators that are less affected by early diagenesis can increase the accuracy of reconstructing paleoclimatic changes. In the large-river dominated marginal seas, the mechanism of land-sea climate coupling evolution stimulated by the paleoclimatic-environmental changes can be elucidated based on paleoclimatic records reconstructed from core lipids GDGTs and long-chain alkyl diols in marine sediments. It is hoped that this paper can provide reliable technical means and a solid theoretical basis for predicting future temperature and rainfall changes.  相似文献   

东北地区湿度梯度下的表土植硅体的空间分布规律     

刘洪妍  王海南  介冬梅  刘利丹  高桂在  李德晖  李楠楠  冷程程  李晨露 《第四纪研究》2019,(1):76-88

植硅体的现代过程研究是恢复古环境的基础,探讨表土植硅体分布及组合特征对环境因子的响应尤为重要。沿中国东北地区年均温为4 ℃等温线采集70块表土样品,研究了单一温度因素控制下表土植硅体的空间分布规律,以期获得不同类型植硅体对降水的响应。研究结果表明:所有表土样品中植硅体丰富且数量较多,主要有棒型、尖型、块状、扇型、扁平状、短鞍型、帽型、哑铃型、齿型、三棱柱型、导管型、硅质突起、硅化气孔、弓型和多面表皮植硅体;且主要以短细胞、棒型、尖型为主,其平均百分含量之和高达80.77%,块状、扁平状、扇型次之,其他类型的植硅体含量较少。方差分析结果表明:棒型、三棱柱型、硅质突起、哑铃型和扁平状在大兴安岭、松嫩平原和长白山之间存在显著性差异,且棒型、三棱柱型、硅质突起的百分含量与年降水量具有极显著的正相关性,哑铃型的百分含量与年降水量具有极显著的负相关性。总之,年均温为4 ℃等温线上70块表土样品中植硅体类型基本相同,但不同类型植硅体的百分含量存在差异,说明本研究区域内表土植硅体组合特征对降水的响应较为敏感。  相似文献