青海热水-日月山断裂带的新活动特征

热水 -日月山断裂带是发育在青藏高原东北缘柴达木 -祁连活动地块内部的 1条重要的NNW向逆 -右旋走滑活动断裂带 ,长约 183km。断裂由 4条不连续的次级断裂段右阶羽列而成 ,阶距 2～ 3km左右 ,在不连续部位形成拉分区。主断裂两端则形成帚状分叉。断裂活动形成了一系列山脊、冲沟和阶地等右旋断错微地貌 ,其中Ⅰ级阶地右旋断错约 8～ 11m ,Ⅱ级阶地右旋断错约 35m。同时沿断裂带还形成了许多断层陡坎 ,Ⅰ级阶地或洪积台地上断层陡坎高约 0 .5～ 1m ,最高达 2 .8m ,Ⅱ级阶地或台地上的断层陡坎高约 2 .5～ 3m ,最高达 4～ 5m。根据相应的阶地年代 ,计算得到断裂带全新世以来的平均水平滑动速率为 3 16mm/a ,垂直滑动速率为 0 .83mm/a     

新疆柴窝堡盆地南缘断层晚第四纪的最新活动和滑动速率

通过航、卫片解译和野外实地踏勘对新疆柴窝堡盆地南缘断层晚第四纪以来的活动特征及活动速率方面有了新的认识:研究认为该断层晚第四纪以来曾有过强烈的活动,断层最新活动在南台子断错乌鲁木齐河Ⅰ级阶地的全新世砂土卵砾石层,形成20～40 cm的垂直断距,在柴窝堡盆地盐湖以南断错冲沟河流Ⅱ级阶地的晚更新世砾石层,垂直断距大于9 m,初步估算晚更新世以来该断层的垂直活动速率为0.09 mm/a,引起的水平缩短速率为0.5 mm/a.作为柴窝堡盆地南缘断层分支的板房沟断层,其最新活动的证据是断错了乌鲁木齐河Ⅰ级阶全新世砾石层.     

塔什库尔干断裂带北段木吉河断层运动特征

塔什库尔干断裂带是由多条运动性质不同的次级断层组成。该断裂带北段的木吉河断层运动特征以逆冲为主,兼有右旋走滑分量。该断层全长20km左右,全新世以来仍有较强活动,断错了全新世中晚期的地貌面,对吉如吉能沟西岸的阶地变形进行测量,得到Ⅰ、Ⅱ阶地的垂直断错量分为10m和14m左右。通过对变形阶地的年代测定,计算得到全新世中期以来,木吉河断层的平均垂直滑动速率为1．8—2．1mm／a,所造成的南北向地壳缩短为1．1～1．3mm／a。     

罗云山山前断裂中段土门-贾朱村晚第四纪断错地貌特征

罗云山山前断裂位于山西临汾盆地西侧,控制着盆地的西界。通过对该断裂1∶ 5万地质填图、对河流冲沟阶地及山前断错地貌的调查,介绍了罗云山山前断裂中段土门-贾朱村晚第四纪断错地貌特征。罗云山山前发育D1、D2、D3 等3 级洪积扇,罗云山山前断裂上升盘冲沟发育T1 ～ T5 等5 级阶地。D1 洪积扇与T1、T2 阶地形成于全新世早中期;D2 洪积扇与T3 阶地形成于晚更新世中晚期;D3 洪积扇与T4、T5 阶地形成于中更新世中晚期。罗云山山前断裂中段不同部位断错地貌特征差异较大,D1 洪积扇的断错在席坊沟一带断距约2. 9m;在金殿镇峪口村南西山前断错约3m。D2 洪积扇的断错在土门镇南西堡子村约2. 5m;在杨家庄村西山前断错约4m;在景村西山前断错约6m;在襄陵镇浪泉沟南西侧山前断错约7. 7m。罗云山山前断裂中段山前断错地貌明显,其最新活动时代为全新世。其中,土门段最新活动时代为全新世早期,龙祠段最新活动时代为全新世中晚期。罗云山山前断裂中段晚更新世中晚期以来活动速率为0. 18～ 0. 54mm / a,由北向南活动呈增强趋势;全新世早中期以来活动速率为0. 4 ～ 0. 9mm / a,断裂活动主要集中于席坊沟-峪口一带。罗云山山前断裂中段从晚更新世中晚期到全新世活动速率有增大的趋势,这与该断裂上升盘冲沟阶地从晚更新世中晚期到全新世抬升速率有增大的趋势以及临汾盆地从晚更新世晚期到全新世沉降速率也有增大的趋势具有较好的一致性。     

东天山地区伊吾断裂晚第四纪活动特征

通过对伊吾断裂的实地调查,发现断裂在伊吾县城北侧的山前地带断错了晚第四纪洪积扇、T_3河流阶地,在地表形清晰的陡坎地貌,T_1阶地未见明显错动。依据探槽及天然露头揭露的剖面,认为研究区内断裂的运动方式以高角度逆冲为主。实测洪积扇上陡坎的高度在5～13 m区间内,T_3阶地的垂直高差达26 m,光释光测年结果表明研究区内T_3阶地的年龄为71～108 ka,初步估计伊吾断裂晚第四纪以来的垂直活动速率为0.24～0.37 mm/a。     

登登山-池家刺窝断裂晚第四纪活动性定量研究

登登山-池家刺窝断裂位于阿尔金断裂东端宽滩山隆起的NE侧,总体走向NW,地貌上表现为醒目的断层陡坎;登登山段长约19km,池家刺窝段长约6.5km。通过卫星影像解译、探槽开挖、断错地貌测量及年龄样品测试等工作,研究了2条断裂的新活动特征。宽滩山NE麓普遍发育3级地貌面,即山前基岩侵蚀台面和冲沟I、Ⅱ级阶地。登登山断裂断错除I级阶地以外的其他地貌面,陡坎高度普遍在1.5m左右,最大高度2.6m。探槽揭露登登山断裂晚更新世以来有3次古地震事件,3次事件的总断距约2.7m,一次事件的垂直断距为0.5~1.2m,事件Ⅰ大约发生于距今5ka;事件Ⅱ大致发生于距今2×10~4a,事件Ⅲ大致发生于距今3.5×10~4a,重复间隔约1.5×10~4a,晚更新世以来的垂直滑动速率约为0.04mm/a。池家刺窝断裂断错了所有3级地貌面,陡坎最大高度为4m,一般在2m左右。探槽揭露池家刺窝断裂晚更新世以来也有3次古地震事件,3次事件的总断距约3.25m,1次事件的垂直位错为0.75~1.5m,晚更新世以来断裂垂直滑动速率为0.06mm/a。池家刺窝断裂古地震事件年代限定较差,但最新1次事件晚于登登山断裂,根据登登山断裂古地震事件的研究结果,推测池家刺窝断裂古地震重复间隔接近于登登山断裂的1.5×10~4a左右。池家刺窝断裂的最新活动时代晚于登登山断裂,1次事件的垂直位错及晚更新世以来的垂直滑动速率都比登登山断裂略大,2条断裂之间还有长约5km的不连续段,被第四纪冲洪积砂砾石层覆盖,地形平坦,断裂地貌特征不发育,这些都表明登登山断裂和池家刺窝断裂具有明显的分段活动特征。阿尔金断裂以北的登登山和池家刺窝断裂规模都不大,垂直滑动速率仅为0.04~0.06mm/a,远小于祁连山断裂及酒西盆地内NW向断裂的垂直滑动速率,反映出构造变形主要限制在高原内部及河西走廊地区,登登山和池家刺窝断裂以低滑动速率、古地震复发间隔很长(10~4a)的缓慢构造变形为特征。     

龙陵-瑞丽断裂(南支)北段晚第四纪活动性特征

遥感影像解译和野外地质地貌调查表明,龙陵-瑞丽断裂(南支)北段是以左旋走滑为主兼张性正断的区域性活动断裂。根据一些断错地貌点的大比例尺填图、实地测量及其年代学分析,确定了该断裂为全新世活动断裂,断裂晚更新世以来的平均水平滑动速率为2.2mm/a,平均垂直滑动速率为0.6mm/a;全新世以来的平均水平滑动速率为1.8～3.0mm/a,平均垂直滑动速率为0.5mm/a。断裂晚更新世以来的滑动速率在不同的时间尺度上变化不大,反映了该断裂晚更新世以来的活动强度比较平稳     

安宁河断裂紫马跨一带晚第四纪地貌变形与断层位移速率

紫马跨一带是安宁河断裂北段晚第四纪断错地层地貌序列保存最好的地区,通过数字影像分析、全站仪实测和探槽开挖,对该地点断错现象进行细致研究,获得了晚全新世以来的左旋位移速率为6·2mm/a,垂直位移速率1·4mm/a;距今约10ka以来的平均左旋位移速率3·6~4·0mm/a,垂直位移速率约为1·1mm/a;距今约20ka以来的左旋位移速率为3·8~4·2mm/a,垂直位移速率最小为0·9mm/a。断层水平和垂直位移速率的比例约为4∶1。断层位移速率在时间分布上的变化与古地震研究的丛集复发特征有较好的一致性,反映断裂的活动强度存在强弱活动的交替现象     

博格达北麓晚第四纪地壳缩短速率

博格达推覆构造,由南向北发育3~4排活动断裂,活动性逐渐向北迁移,最新活动主要集中在前缘的阜康断裂及北三台断裂上。阜康断裂上盘在二工河一带为单斜岩层,具有断弯褶皱的特征,通过测量阶地拔河高度、阶地基座岩层的产状以及阶地年代数据,应用断弯褶皱变形的关系式得到了断层沿断层面滑动速率为0.8 mm/a;北三台断裂发育在断层扩展褶皱北三台背斜北翼,利用阶地剩余面积及褶皱滑脱面埋深,计算得到北三台背斜晚更新世晚期以来的缩短速率在0.5~0.9mm/a之间。综合得到博格达北麓晚第四纪地壳缩短速率为1.3~1.7 mm/a,考虑到埋藏地貌面的变形量,估计博格达北麓晚第四纪以来南北向总的地壳缩短速率在1.5~2.0 mm/a之间。     

天全-荥经断裂晚第四纪活动的地貌证据

天全-荥经断裂是青藏高原东南缘的1条晚第四纪且活动资料较少的断裂,在2008年汶川M 8.0地震之后,龙门山断裂带西南端未来的地震危险性受到关注。对天全-荥经断裂晚第四纪活动特征的获取有助于理解该区地震危险性的评价。通过遥感影像解译,结合野外调查和断错地貌测量,分析了天全-荥经断裂在荥经下坝村至桂花村切过荥经河河谷晚第四纪地貌区的活动证据。断裂沿线形成冲积扇断错、阶地坎断错和断坎等地貌,并沿断裂发育滑坡。晚第四纪以来断裂以左旋走滑活动为主,其中T2/T2'阶地坎被左旋断错22—24m。利用荥经河阶地与青衣江河流阶地对比,认为该断裂20—40ka以来左旋走滑速率为0.6—1.1mm/a。仍需要从古地震等方面开展工作,来进一步确定天全-荥经断裂的地震危险性。     

Changes in sediment transport in the Kuye River in the Loess Plateau in China

In this paper, the changes in sediment transport over 51 years from 1955 to 2006 in the Kuye River in the Loess Plateau in China are assessed. Key factors affecting sediment yield and sediment transport, such as precipitation depth, discharge, and human activities are studied. To investigate the changes in sediment yield in this watershed, a trend analysis on sediment concentration, precipitation depth, and discharge is conducted. Precipitation depths at 2 Climate Stations （CSs）, as well as discharge and sediment transport at 3 Gauging Stations （GSs） are used to assess the features of sediment transport in the Kuye River. The rtmoff modulus （defined as the annual average discharge per unit area, L/（s·km^2）） and the sediment transport modulus （defined as the annual suspended sediment transport per unit area, t/（yr km^2）） are introduced in this study to assess the changes in runoff and sediment yield for this watershed. The results show that the highest average monthly discharge during the study period in the Kuye River is 66.23 m^3/s in August with an average monthly sediment concentration of 88.9 kg/m^3. However, the highest average monthly sediment concentration during the study period in the Kuye River is 125.34 kg/m^3 and occurs in July, which has an average discharge of 42.6 m^3/s that is much less than the average monthly discharge in August. It is found that both the runoff modulus and sediment transport modulus at Wenjiachuan GS on the Kuye River has a clear downward trend. During the summer season from July to August, the sediment transport modulus at Wenjiachuan GS is much higher than those at Toudaoguai and Longmen GSs on the Yellow River. The easily erodible loess in the Kuye River watershed and the sparse vegetation are responsible for the extremely high sediment yield from the Kuye River watershed. The analyses of the grain size distribution of suspended load in the Kuye River are presented. The average monthly median grain size of suspended load in the Kuye River is largest in February and then decreases until June. In July, the average monthly median grain size of suspended load approaches another peak and decreases until September. Then, the median grain size of suspended load starts to increase until February of the following year. However, the average monthly median grain size of suspended load in the Yellow River at Toudaoguai and Longmen GSs is the smallest between early summer and late fall The median grain size in the Yellow River starts to increase in November and approaches the largest size in January.     

Variations in trace gas concentrations in different environments in India

Observations of trace gases (SO₂, NH₃, NO₂ and O₃) were made during the period 1981 to 1984 at 6 different locations representative of urban industrial, urban, nonurban, thermal power plant and marine environment. Diurnal variations of the trace gases were studied in an urban environment. Except in the urban industrial environment, the concentration of NH₃ was found in the range of background values. Also, the average concentrations of NO₂ and O₃ at the different environments were in the order of background values. However, the concentrations of SO₂ were substantially higher by about 7 times, in urban industrial and thermal power plant environments. The diurnal variations of SO₂, NH₃ and NO₂ showed anitphase relationship with surface temperature at the urban environment station which is relatively free of industrial pollution. Discussion is centred on trace gas variations in different environments in India together with the values reported for various countries in the world.     

TritiogenicHe in groundwater in Takaoka

³He/⁴He ratios up to 3.5 times the ratio of atmospheric He were found in groundwater samples. The³He enrichment can be attributed to radiogenic³He produced by in-situ beta-decay of³H. This shows that tritiogenic³He is accumulating in confined waters. From tritiogenic³He and³H concentrations, ages of groundwaters can be calculated. Detection of tritiogenic³He gives a tool to trace a tritium contamination which occurred in the past and cannot be assessed only by the³H counting method.     

2008年云南地震灾害概况

列出了2008年云南省破坏性地震目录.在此基础上,结合云南省地震局的地震灾害评估资料,总结了2008年云南地震灾害的主要数据和特性.最后列出1990～2008年云南地震灾害的相应数据,并进行了简要对比.     

Applied volcanology in geothermal exploration in Iceland

In an active spreading area like Iceland, where the regional geothermal gradient is in the range 50–150°C/km, it is normally not a problem to find high enough temperature with deep drilling, but the difficulties arise with finding permeable layers at depth within the strata. Various volcanological methods can be applied in the search for aquifers and geothermal reservoir rocks. The flow pattern (as deduced from deuterium studies) indicates that the thermal water flows preferentially along high porosity stratiform horizons and dyke swarms from the recharge areas in the highlands to the hot spring areas in the lowlands. The primary porosity of the volcanic strata is dependent on the chemical composition and the mode of eruption of the volcanic units. Both the reservoir rocks and the flow channels forming the geothermal plumbing system are thought to vary from the Tertiary to the Quaternary provinces due to environmental conditions at the eruptive sites.     

2007年中国大陆地震灾害损失述评

在列出2007年中国5级以上地震目录的基础上,结合有关省(自治区、直辖市)地震局的地震灾害评估资料,总结出2007年中国大陆地震灾害的主要数据和特性。最后列出1990—2007年中国大陆地震灾害的相应数据,并进行了简要的比较。     

Projected changes in flood indices in selected catchments in Poland in the 21st century

The aim of this study is to estimate likely changes in flood indices under a future climate and to assess the uncertainty in these estimates for selected catchments in Poland. Precipitation and temperature time series from climate simulations from the EURO-CORDEX initiative for the periods 1971–2000, 2021–2050 and 2071–2100 following the RCP4.5 and RCP8.5 emission scenarios have been used to produce hydrological simulations based on the HBV hydrological model. As the climate model outputs for Poland are highly biased, post processing in the form of bias correction was first performed so that the climate time series could be applied in hydrological simulations at a catchment-scale. The results indicate that bias correction significantly improves flow simulations and estimated flood indices based on comparisons with simulations from observed climate data for the control period. The estimated changes in the mean annual flood and in flood quantiles under a future climate indicate a large spread in the estimates both within and between the catchments. An ANOVA analysis was used to assess the relative contributions of the 2 emission scenarios, the 7 climate models and the 4 bias correction methods to the total spread in the projected changes in extreme river flow indices for each catchment. The analysis indicates that the differences between climate models generally make the largest contribution to the spread in the ensemble of the three factors considered. The results for bias corrected data show small differences between the four bias correction methods considered, and, in contrast with the results for uncorrected simulations, project increases in flood indices for most catchments under a future climate.     

Advances in ground motion studies in China

This paper briefly summarizes the works in the processing of strong ground motion data, the factors affecting strong ground motion, the modeling of strong ground motion and the calculating of broad-band response spectrum which have been done recent years by engineering seismologists and seismologists of China. In addition, we think back to the international cooperation in strong ground motion of the recent years and make some expectations for the future.     

冬季亚洲中强震与夏季我国东部主雨带的准同纬性

根据1954～2003年50年亚洲中强震与我国地温资料，分析了冬季震中纬度—震涡中心纬度—冬季我国东部强地热涡中心纬度—夏季我国东部主雨带纬度4者之间的相互关系，发现冬季中强震与夏季主雨带之间具有较好的准同纬性. 这是每年汛期降水预报的一个指标. 文中也讨论了应用此预报指标时的一些特例.