中国大陆中强以上地震余震分布尺度的统计特征   总被引：10，自引：0，他引：10       下载免费PDF全文

蒋海昆  郑建常  吴琼  曲延军  李永莉  代磊 《地震学报》2007,29(2):151-164

依据1970年以来记录相对完备的MSge;5.0地震序列资料，统计研究了中国大陆余震分布尺度与序列最大地震震级M0及最大地震破裂形式之间的关系. 在95%置信概率下，考虑主震破裂形式， 分序列类型给出了余震分布尺度与M0之间的统计关系. 定性而言，余震分布尺度的对数lgR与M0正相关， 但数据分布较为离散. 分类型来看， 孤立型序列余震分布尺度与M0之间统计相关程度低， 余震分布尺度介于5~60 km之间； 主余型序列lgR与M0正相关； 多震型序列当M0le;6.2时lgR与M0之间相关性不显著，余震分布尺度介于5~70 km之间， 当M0ge;6.3时lgR与M0线性相关. 统计结果还表明， 走滑近走滑及斜滑型主震所导致序列类型比例之间没有显著差异，而倾滑近倾滑型主震（主要为逆断型破裂）所导致的主余型序列所占比例较高， 孤立型及多震型序列所占比例则相对较低. 对比研究显示， 当M0较高时，余震分布尺度主要取决于主震大小而与主震破裂形式关系不明显.   相似文献   

Shallow seismic refraction analysis: Application to studying the active North Sakhalin fault     

V. V. Zhigulev  V. N. Patrikeev 《Russian Journal of Pacific Geology》2007,1(1):15-21

Results are presented from a seismic refraction survey (P-S waves) carried out in different years on recent faults of North Sakhalin. Structural features of the near-surface zone of active faults with different types of tectonic motions and their imaging in seismic fields are demonstrated. Criteria for estimating the activity of the studied tectonic disruption are proposed.  相似文献   

构造环境应力场在确定新疆地震危险区中的应用   总被引：2，自引：0，他引：2  

陈培善  白彤霞 《内陆地震》1998,12(1):1-12

基于断裂力学的研究成果和位错论,提出了断裂力学地震破裂模式,进而推导出了几个从地震波观测资料直接计算震源处构造环境剪力场量值ｒ０的公式。根据这些公式计算了中国地区中小地震的构造环境剪应力值。结果表明：ｒ０值的大小与分布和大震发生的地点有密切关系,即剪应力水平较高的地区将容易发生大地震,而剪应力水平较低的地区通常只发生小地震。据此,从１９９２年开始,根据环境应力场进行寻找地震危险区的尝试总有效北达７  相似文献   

走滑活动断裂的障碍体与地震破裂的关系     

袁道阳  刘小凤 《华南地震》1998,18(4):35-40

系统收集了中国大陆走滑活动断裂带上障碍体（阶区）与地震破裂的资料,探讨了障碍体止裂尺度与地震破裂的关系及其分段意义。统计分析表明,走滑活动断裂带上地震的震级与障碍体的阶距、阶距与次级段长度具有较好的线性关系。障碍体的阶距可以作为判定地震破裂止裂尺度的极重要标志,是进行破裂分段的前提和基础。  相似文献   

1927年古浪8级大震地表破裂特征及形成机制   总被引：10，自引：3，他引：7       下载免费PDF全文

侯康明 《地震地质》1998,20(1):20-26

野外考察结果表明,１９２７年古浪８级大地震造成了６段不同规模、不同方向、不同力学成因、不同等级的地表破裂,构成了呈面状分布的复杂地震破裂带,与我国西部地区由走滑断层运动形成的破裂带相比具有较大差异。其中的４段破裂与极震区及余震分布的位置相重合,主体散布在冬青顶北麓一带,沿皇城－双塔活动断裂的东段和武威－天祝活动断裂北段分布,是１９２７年古浪地震的主破裂带。其余两段分别分布在Ⅸ度区内的皇城－双塔断裂中段和西山堡－滴水崖断裂带上,是高烈度区内的次级破裂。４段主破裂是在统一构造应力场作用下形成的产物,具有统一变形机制。其中冬青顶张性破裂带是发育在山前下方寨－严家新庄逆断层上盘的次级张性破裂,而主破裂是由逆断层运动在寺儿沟滩等处的山前洪积台地上产生的  相似文献   

THE PALEOSEISMIC SURFACE RUPTURE AT SOUTH OF CENTRAL ALTYN TAGH FAULT AND ITS TECTONIC IMPLICATION          下载免费PDF全文

SHAO Yan-xiu  YUAN Dao-yang  LIU-ZENG Jing  Jerome Van der Woerd  LI Zhi-gang  WU Lei  LIU Fang-bin 《地震地质》1979,42(2):435-454

In this study, we described a 14km-long paleoearthquakes surface rupture across the salt flats of western Qaidam Basin, 10km south of the Xorkol segment of the central Altyn Tagh Fault, with satellite images interpretation and field investigation methods. The surface rupture strikes on average about N80°E sub-parallel to the main Altyn Tagh Fault, but is composed of several stepping segments with markedly different strike ranging from 68°N~87°E. The surface rupture is marked by pressure ridges, sub-fault strands, tension-gashes, pull-apart and faulted basins, likely caused by left-lateral strike-slip faulting. More than 30 pressure ridges can be distinguished with various rectangular, elliptical or elongated shapes. Most long axis of the ridges are oblique(90°N~140°E)to, but a few are nearly parallel to the surface rupture strike. The ridge sizes vary also, with heights from 1 to 15m, widths from several to 60m, and lengths from 10 to 100m. The overall size of these pressure ridges is similar to those found along the Altyn Tagh Fault, for instance, south of Pingding Shan or across Xorkol. Right-stepping 0.5~1m-deep gashes or sub-faults, with lengths from a few meters to several hundred meters, are distributed obliquely between ridges at an angle reaching 30°. The sub-faults are characterized with SE or NW facing 0.5~1m-high scarps. Several pull-apart and faulted basins are bounded by faults along the eastern part of the surface rupture. One large pull-apart basins are 6~7m deep and 400m wide. A faulted basin, 80m wide, 500m long and 3m deep, is bounded by 2 left-stepping left-lateral faults and 4 right-stepping normal faults. Two to three m-wide gashes are often seen on pressure ridges, and some ridges are left-laterally faulted and cut into several parts, probably owing to the occurrence of repetitive earthquakes. The OSL dating indicates that the most recent rupture might occur during Holocene.
Southwestwards the rupture trace disappears a few hundred meters north of a south dipping thrust scarp bounding uplifted and folded Plio-Quaternary sediments to the south. Thrust scarps can be followed southwestward for another 12km and suggest a connection with the south Pingding Shan Fault, a left-lateral splay of the main Altyn Tagh Fault. To the northeast the rupture trace progressively veers to the east and is seen cross-cutting the bajada south of Datonggou Nanshan and merging with active thrusts clearly outlined by south facing cumulative scarps across the fans. The geometry of this strike-slip fault trace and the clear young seismic geomorphology typifies the present and tectonically active link between left-lateral strike-slip faulting and thrusting along the eastern termination of the Altyn Tagh Fault, a process responsible for the growth of the Tibetan plateau at its northeastern margin. The discrete relation between thrusting and strike-slip faulting suggests discontinuous transfer of strain from strike-slip faulting to thrusting and thus stepwise northeastward slip-rate decrease along the Altyn Tagh Fault after each strike-slip/thrust junction.  相似文献   

On mixing processes in cumulus clouds     

J. Warner 《Pure and Applied Geophysics》1980,119(4):809-815

An examination is made of the hypothesis that internal cloud properties are determined by the mixing of dry air from above the cloud top and cloud base air in such a way that the mixture is neutrally buoyant with respect to the clear air environment at each level. It is concluded that the resulting mixture is much drier than is actually observed. Comments are made about observed cloud properties which need to be taken into account in any model of the mixing process.  相似文献   

Summertime Mixing Heights At Vienna, Austria, Estimated from Vertical Soundings and by a Numerical Model   总被引：1，自引：1，他引：0  

Martin Piringer 《Boundary-Layer Meteorology》1998,89(1):25-45

Mixing heights calculated by the Danish OML meteorological pre-processor are compared to those diagnosed from radio- and tether-sonde vertical potential temperature profiles. All methods give reliable estimates of noon mixing heights deduced from radiosoundings, especially when the boundary layer is fully convective. Differences are larger during convective conditions without a well-defined capping inversion in the radiosonde potential temperature profile or when OML calculates a mechanical mixing height. The OML model is also able to calculate the daily course of the mixing height as expected. The tethersonde-derived mixing heights are especially valuable during the morning rise of the elevated inversion. Modifications to all three methods to improve mixing-height predictions are discussed.  相似文献   

Discrete modelling of time‐dependent rockfill behaviour     

Claire Silvani  Thierry Désoyer  Stéphane Bonelli 《国际地质力学数值与分析法杂志》2009,33(5):665-685

This modelling study deals with the time‐dependent behaviour of rockfill media, which is of particular interest during the life of rockfill dams. Breakage of rock blocks and crack propagation are the main processes responsible for rockfill creep and collapse. The modelling procedure presented here is performed on two scales: on the rock block scale, where the grain is taken to be an assembly of rigid particles initially endowed with cohesive bonds, and on the rockfill scale, which is taken to involve a set of breakable grains interacting via contact and friction processes. The grain breakage process is described in term of a thermodynamically consistent damage interface model, where the damage is a gradual delayed process. This model was implemented in a non‐smooth contact dynamics code. The effects of the main parameters involved were analysed by performing numerical studies. The ability of the model to predict the creep behaviour of rockfill media is confirmed by presenting several simulations. Copyright © 2008 John Wiley & Sons, Ltd.  相似文献   

Simultaneous inversion of waveform and geodetic data for the rupture process of the 1984 Naganoken–Seibu, Japan, earthquake     

Shingo Yoshida  Kazuki Koketsu 《Geophysical Journal International》1990,103(2):355-362

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