山西长治断裂的基本特征与第四纪活动性研究

实地调查表明,山西长治断裂由三段组成,南段和中段为西倾正断层,北段为东倾正断层,总体走向北东25o,长达65km,控制着附近山地与第四纪山间盆地的构造演化和地貌发育;第四纪早期,断裂发生强烈的垂直差异活动,最大垂直活动幅度可达400m左右;第四纪晚期,断裂活动性明显减弱,中段仍有活动,至少发生过两期活动,第—期活动发生于距今10.88万年左右或以后、1.49万年以前,第二期活动发生于距今1.49万年以后,垂直错距0.65m。     

从中国、美国、欧洲抗震设计规范谱的比较 探讨我国的抗震设计反应谱

本文分析了中国、美国、欧洲 3 种抗震设计规范的地震动参数取值,并比较了 3 种抗震设计反应谱。结果表明,总体上说,欧洲、美国规范的加速度短周期反应谱高于中国规范。但随着周期的扩大,由于中国规范中反应谱的下降指数较小,导致了中国规范中的反应谱逐渐接近并可能超过了欧洲、美国规范。本文的结果可为我国未来抗震设计规范修订,以及地震安全性评价工作中确定设计反应谱提供参考。     

郑州老鸦陈断裂的探测与活动性调查研究

通过浅层地震勘探、钻孔联合剖面分析、野外地貌调查以及新地质年代测定等技术方法,对原先认定的郑州老鸦陈断裂的活动性开展调查. 其中,浅层地震勘探结果表明,该断裂仅存在于新近纪以前的地层,而在新近纪地层内均未发现该断层错断和活动迹象. 同时,地表的地质地貌调查亦发现ldquo;地貌陡坎rdquo;与老鸦陈断裂的位置不一致. 另外钻探和钻孔联合剖面的分析也表明,地表的陡坎仅发育在马兰黄土中, 其下地层平缓,没有错断现象,认为该陡坎的形成与老鸦陈断层没有关系,但可能与黄河改道变迁的侵蚀作用有关. 因此,老鸦陈断裂不属于活动断裂.      

Tectonic facies and the archipelago-accretion process of the West Kunlun,China

A tectonic facies investigation carried out in the West Kunlun, China allows us to have worked out a tectonic model of orogen. The tectonic facies, from the north to the south, are composed of the following: 1. Southern Tarim tectonic realm; 2. North Kudi magmatic arc; 3. Kudi mélange; 4. Kudi micro-continent; 5. main shear zone; 6. Xianan Bridge calc alkaline complex; 7. Mazar-Kangxiwar mélange-accretion complex; and 8. Tianshuihai foreland fold-thrust belt. The tectonic facies 1»5 recorded the history of the northward subduction of the Prototethys and southward accretion of Eurasia in the Late Proterozoic-Early Paleozoic time, while the tectonic facies 6»8 recorded the history of the northward subduction of the Paleotethys and southward accretion of Eurasia in the Late Paleozoic-Early Mesozoic time, that of the tectonic evolution of the passive margin of the Qiangtang block, and that of the docking, and the final amalgamation of the Qiangtang block to the Eurasian continent. The tectonic facies investigation has indicated that a complicated archipelago-accretion orogenesis took place in the West Kunlun orogen, which was the important character of southward growth of the Eurasian continent.     

Tectonic facies and the archipelago-accretion process of the West Kunlun,China

A tectonic facies investigation carried out in the West Kunlun, China allows us to have worked out a tectonic model of orogen. The tectonic facies, from the north to the south, are composed of the following: 1. Southern Tarim tectonic realm; 2. North Kudi magmatic arc; 3. Kudi mélange; 4. Kudi micro-continent; 5. main shear zone; 6. Xianan Bridge calc alkaline complex; 7. Mazar-Kangxiwar mélange-accretion complex; and 8. Tianshuihai foreland fold-thrust belt. The tectonic facies 1»5 recorded the history of the northward subduction of the Prototethys and southward accretion of Eurasia in the Late Proterozoic-Early Paleozoic time, while the tectonic facies 6»8 recorded the history of the northward subduction of the Paleotethys and southward accretion of Eurasia in the Late Paleozoic-Early Mesozoic time, that of the tectonic evolution of the passive margin of the Qiangtang block, and that of the docking, and the final amalgamation of the Qiangtang block to the Eurasian continent. The tectonic facies investigation has indicated that a complicated archipelago-accretion orogenesis took place in the West Kunlun orogen, which was the important character of southward growth of the Eurasian continent.

     

新疆与其边境地区、内蒙古地区及华东、华南与台湾部分地区未来强震预测

运用孕震断层多锁固段脆性破裂理论与有关预测方法,对新疆与其边境地区、内蒙古地区及华东、华南与台湾部分地区各地震区未来的地震趋势进行了分析,给出了未来有大地震发生的地震区地震震级、地点、临界应变(对应发震时间)、震源深度在内的四要素预测结果.得出的结论可供有关部门参考,以制定相应的防震减灾措施.     

Glacial advances and ESR chronology of the Pochengzi Glaciation,Tianshan Mountains,China

The Pochengzi Glaciation is a typical glaciation in Quaternary in the Tianshan Mountains. The glacial landforms comprise several integrated end moraines, like a fan spreading from the north to the south at the mouth of the Muzhaerte River valley and on the piedmont on the southeastern slope of the Tumur Peak, the largest center of modern glaciation in the Tianshan Mountains. The landforms recorded a complex history of the ancient glacier change and contained considerable information of the glacial landscape evolution, and dating these landforms helps us understand the temporal and spatial shifts of the past cryosphere in this valley and reconstruct the paleoenvironment in this region. Electron spin resonance (ESR) dating of the glacial tills in the upper stratum from a well-exposed section, end moraines, and associated outwashes was carried out using Ge centers in quartz grains, which are sensitive to the sunlight and grinding. The results could be divided into three clusters, 13.6–25.3, 39.5–40.4 and 64.2–71.7 ka. Based on the principle of geomorphology and stratigraphy and the available paleoen- vironmental data from northwestern China, the end moraines were determined to deposit in the Last Glaciation. The landforms and the three clusters of ages demonstrate that at least three large glacial advances occurred during the Pochengzi Glaciation, which are corresponding to marine oxygen isotope stage 4 (MIS4), MIS3b and MIS2. The landforms also indicate that the gla- ciers were compound valley glacier in MIS2 and MIS3b and piedmont glacier in MIS4, and the ancient Muzhaerte glacier were 94, 95 and 99 km at their maximum extensions in these three glacial advances.     

Occurrence,shape and movement of daily rainfall in the Huai Basin,China

The upper reaches of the Huai River in Central China are located in the East Asian monsoon region. Strong seasonality, as well as large interannual variability of rainfall, causes floods and an uneven supply of water. In order to conserve the water and mitigate the floods, dams and flood protection structures are constructed. Their design requires information about the rainfall. Daily observations from 1957 to 1986 from 78 rain gauges were used to study shape, orientation, movement and geographical and seasonal occurrence of storms in the 79 000 km² study area. The rainfall characteristics were described using graphical plots, cross‐ and autocorrelation. Storms larger than 50 mm/day were found to occur from February to November, whereas storms exceeding 350 mm/day were confined to the main rainfall season from late June to mid‐August. The southern part of the study area experienced a break in the rainfall season in late July, corresponding to the seasonal northward shift of the rain belt. A weekly periodicity of 7–8 days for rainfall was found during June–July, but not during August–September. During the whole period June–September, the spatial pattern of daily rainfall revealed an elongated shape, more pronounced during June–July than August–September. The rainfall area was orientated approximately from WSW to ENE during the whole period, and showed an anticlockwise rotation of about 16° per day during June–July. The cross‐correlation analysis revealed that the rainfall area moved about 100 km/day eastward. These results and an investigation of meteorological maps indicate that the spatial correlation pattern of daily rainfall is produced by cold fronts on the Mei‐Yu front. Suggestions are made as to how to use the results for the construction of design rainfalls in the study area. Copyright © 1999 John Wiley & Sons, Ltd.     

Geochronology,petrology,and geochemistry of the Yaojiazhuang ultramafic-syenitic complex from the North China Craton

The Yaojiazhuang ultramafic-syenitic complex is one of the representative Triassic alkaline plutons on the northern margin of the North China Craton(NCC).Based on detailed study of the zircon U-Pb age,petrological,mineralogical,and geochemical data of the complex,the characteristics of the magmas system,the petrogenesis of different rock types,and the nature of the mantle source were discussed to provide new constraints on the origin and tectonic setting of the Triassic alkaline belt.Cumulus ultramafic rocks,clinopyroxene-syenites and syenites are the main rock types of the complex.The zircons from the syenites yielded a U-Pb age of 209 Ma.Diopside-augite,biotite,and sanidine-orthoclase are the major minerals,with subordinate apatite and magnetite.Rocks from the complex are enriched in large ion lithophile elements(LILE)and light rare earth elements(LREE),depleted in high field strength elements(HFSE)and heavy rare earth elements(HREE),and the initial 87Sr/86Sr ranges from 0.7057 to 0.7061 and ε Nd(t)from-9.4 to-11.4.Mineralogy and geochemical data demonstrate that the parent magma of the complex is SiO2-undersaturated ultrapotassic alkaline-peralkaline,and is characterized by high CaO content and fluid compositions(P2O5,CO2,H2O),and by high oxygen fugacity and high temperature.The complex was originated from a phlogopite-clinopyroxenite-rich lithospheric mantle source in the garnet-stable area(> 80 km)that had previously been metasomatized by melts/fluids from altered oceanic crust.The parent magma has been contaminated by little ancient TTG gneisses during magma emplacement.The development of the Yaojiazhuang complex indicates that the northern margin of the NCC has entered into an extensively extensional regime in the Late Triassic.     

2008年5月12日汶川地震谱震级及相关问题研究(英文)

基于P波和S波的谱震级特征对汶川地震进行了定量研究,可以看出P波和S波的最大谱震级出现在不同的周期上。对这一现象的构造物理意义进行了讨论,推测相对于P波而言,地震发生期间辐射的S波能量来自异常大的震源体积。选择部分全球地震的谱特征为背景,对汶川地震的体波谱震级特征进行了分析,结论是汶川地震的特征与其所处的周边环境是一致的。     

福建仙游地震序列的震源机制解

1,209 earthquakes occurred in Xianyou, Fujian from August 4, 2010 to October 4, 2013. The largest earthquake was ML5.0 on September 4, 2013. In order to study the Xianyou earthquake sequence and understand the causative structure and stress field of Xianyou, the focal mechanism solutions of six earthquakes （ ML 〉 3. 5 ） in the Xianyou earthquake sequence are calculated using the broadband digital data of the Fujian Seismic Network with the seismic moment tensor inverse method. The results show that the focal faults of the six earthquakes are similar, which are all strike-slip faults striking to the northwest with high dip angles. The direction of the principal compressive stress axes is near SN, which is different from the stress field of Fujian region. The Xianyou earthquake sequence may have been induced by the stress adjustment after the impoundment of Jinzhong reservoir.     

长白山天池火山研究进展

长白山天池火山距今４１０５年以来至少发生过两次大规模喷发。其最近的一次大喷发发生于公元８５０～１０４０年间。估计了这次喷发的喷发物体积和Ｃ１，Ｆ，Ｓ等的释放量。数值模拟表明，该次大喷发对全球气候变化产生过重要影响，最近的地球物理探测结果显示，在该火山下面存在地壳和上地幔双层岩浆房。认为该火山现在仍是一座具潜在灾害性大喷发危险的现代活动火山。     

Temporal and spatial variation and stability of the oasis in the Sangong River Watershed, Xinjiang, China

The unique ecological landscapes are composed of the mountain systems with the obviousvertical differentiation, vast natural desert systems, and oasis systems on which the human beings rely for the existence in the arid areas in West China. Oases are the …     

Arsenic in the Yellow river,China

Data collected since 1973 show high levels of arsenic in the Yellow River, very largely from natural sources. Average and peak concentrations, and the downstream distribution of the arsenic suggest the most likely source as the loess which provides 90 per cent of the river's suspended load. Arsenic is strongly absorbed by the silt and clay in the river: some of it is deposited in reservoirs and delta sediments but most is carried out to sea.     

Pseudotachylytes from the Koktokay-Ertai fault zone, Xinjiang, China, and their seismogeologic implications

Multi-period of pseudotachylytes of variable occurrences and shapes are widely outcropped in Haizikou and Mukurasen sections of the Koktokay-Ertai fault zone. They consist of clasts and matrix. The clasts comprise fine fragments of the host rock (mylonite) and quartz grains, while the matrix consists of cryptocrystalline and glassy materials which contain fibrous and radial microlites. The chemical compositions of the pseudotachylytes resemble those of the host rocks. Their features indicate that the pseudotachylytes were formed from local melting of the mylonites during the rapid movement of the fault, and that the formation depth was 10—12 km. The geologic event that produced pseudotachylytes is believed to be paleoearthquake. Project supported by the Joint Earthquake Science Foundation.     

Nonlinear advection,Coriolis force,and frictional influence in the South Channel of the Yangtze Estuary,China

Observation data of along-estuary and lateral current velocities over a transect located at the South Channel of the Yangtze estuary was obtained during a spring tide in August 2011.Harmonic analysis was done on the current velocities to get a mean component and a semi-diurnal component.Based on these two components,the driving mechanisms of mean lateral flow and M2 lateral tidal flow are shown and analyzed respectively.The dominant driving force of mean lateral flow is nonlinear advection and that of lateral M2 tidal flow is Coriolis force.The friction plays an important role near the bottom and surface for both lateral mean flow and M2 tidal flow.     

紫坪铺水库库区地震精定位研究及分析

利用双差定位法, 对紫坪铺水库台网8个地震台站记录到的2004年8月16日至2008年5月10日的1569个小震进行重新定位。 结果显示, 重新定位后的小震主要集中分布在龙门山推覆构造带的中央北川—映秀断裂、 前山灌县-江油断裂和后山汶川—茂汶断裂上, 其中大部分地震位于北川—映秀断裂并收敛于紫坪铺水库的两端, 走向NE向; 震源深度集中在5~15 km范围内, 平均深度为7.8 km, 15~30 km也有少量地震发生。 水库区域小震活动频度与水库水位存在一定的相关性。 精定位后, 到时残差的均方根平均值为0.048 s, 震源位置的估算误差在水平方向上平均为0.63 km, 在垂直方向上平均为0.51 km。 文中还讨论了紫坪铺水库区震源分布和地质构造的关系。