共查询到20条相似文献，搜索用时 437 毫秒
1.
本文以滑波理论为依据，总结了山西地震带的两种不同特点的滑坡。即：振荡式滑坡及触发式滑坡。虽然两种滑坡都可分为变形、解体、滑动、毁灭等四个阶段，但其动力不同。振荡式滑波的滑动面倾角小，因而滑力来源于强震振动，而触发式滑坡的滑动面倾角大，因而滑力来自滑体本身静荷载。对两种滑坡的研究对预防及减轻强震带来的次生灾害有重要的意义。 相似文献
2.
2013年四川省芦山“4.20”7.0级强烈地震触发滑坡 总被引：5，自引：2，他引：3
2013年4月20日,四川省芦山县发生了MS7.0地震.文中简要介绍了芦山地震的基本情况与芦山地震区历史地震及其相关地震滑坡情况.依据2008年汶川地震滑坡与地震动峰值加速度(PGA)的空间关系,对芦山地震滑坡大体分布范围进行了推测.根据地震滑坡分类学,将芦山地震滑坡分为破坏型滑坡、连贯型滑坡、流滑型滑坡3大类.其中,破坏型滑坡包括岩质崩塌、岩质滑动、岩质崩滑、土质崩塌、土质滑动等5类;连贯型滑坡包括土质坍塌与慢土流2类;流滑型滑坡为快速流滑.破坏型滑坡如岩质崩塌、岩石滑动、土质崩塌这3类是芦山地震滑坡中最常见的类型.基于震后可利用的高分辨率航片,初步解译得到3 883处滑坡位置点数据.最后,从余震对滑坡的影响,芦山地震滑坡与邻区地震滑坡对比分析,对后续基于高分辨率遥感影像的滑坡精细解译的启示等3个方面开展了分析与讨论. 相似文献
3.
西山村滑坡位于地震活动性剧烈的龙门山地区,这个区域有大量的滑坡在汶川地震中被触发,此后西山村滑坡发生持续变形.为了监测该滑坡体的运移和局部破裂产生的微弱的地震信号,由微震事件获取滑坡滑动和变形模式,2015年八月底至十一月底,我们在滑坡上布置了30套地震仪.首先通过信号到时和波形特征把滑坡上的微震信号从人类活动产生的信号和滑坡体以外的区域地震信号区分开来.然后以识别到的微震波形为模板,用滑动时窗互相关的方法匹配其他的微震事件.结果表明,96个微震事件能被30个台站都记录到.通过对这些事件的定位,我们发现大部分（80个）能被所有台站记录到的事件发生在滑坡的底部,其他的少部分（16个）发生在滑坡的顶部.这意味着有相当多的能量积聚在滑坡的顶部和底部,而滑坡的底部则更活跃.除此外,在滑坡的中部有较多更微弱的事件被周围的部分仪器记录到.基于这些微震事件的位置,我们发现四个辐射地震信号的不稳定区域和钻孔监测到的不稳定区域比较吻合.这些辐射地震信号的不稳定区域应该和滑坡体的运动和内部变形相关.由此表明,地震学方法也是监测滑坡的变形的有效手段,是现有监测手段的有力补充. 相似文献
4.
5.
古浪地震滑坡的分布规律和构造意义 总被引：11，自引：0，他引：11
１９２７年古浪地区发生了一次８级地震，地震时诱发了大量的滑坡和崩塌。本文根据野外调查和航片解译，分析了古浪地震滑坡的分布规律，探讨了古浪地震的地面破坏类型和滑坡滑动方向与区域构造应力场的关系。 相似文献
6.
为了解决滑坡治理过程中的稳定性分析问题,将GeoStudio软件应用于滑坡稳定性分析计算中。以陕西巨亭滑坡为例,采用极限平衡法、滑面应力分析的有限元法分别进行了稳定性计算。对比分析2种计算方法得到的安全系数和潜在滑动面得出：安全系数较勾接近,但有限元法得出的潜在滑动面更准确。GeoStudio软件可以方便的计算出边坡安全系数,直观的表达出潜在滑动面,为滑坡的治理分析提供可靠依据。 相似文献
7.
2008年5月12日在青藏高原与四川盆地交界的龙门山山脉发生了Ms8.0级强烈地震,引发山体滑坡等地质灾害,造成了巨大的人员伤亡和经济损失.本文利用远场体波波形记录结合近场同震位移数据,根据地质资料和地震形成的地表破裂轨迹,构造了一个双“铲状”有限地震断层模型,利用反演技术重建地震的破裂过程.结果显示汶川大地震主要是沿龙门山构造带的映秀-北川断裂和灌县-江油断裂发生的逆冲兼右旋走滑破裂事件.断层面上的滑动分布显示两个高滑动区先后发生在地震破坏最为严重的映秀和北川地区,最大滑动量高达1200～1250 cm,且破裂过程也显示一定的复杂性.地震破裂的平均走滑量略大于平均倾滑量,与多种观测资料获得的震前龙门山断裂带构造变形相一致,推断是由于长期区域应力场作用和龙门山地区特殊的物质组成和结构孕育了这次千年尺度的强烈地震. 相似文献
8.
本文对典型的黄土滑坡进行研究,研究区域位于我国甘肃省永靖县盐锅峡的黑方台地区．具体方法为：首先对不同时序的黑方台滑坡监控视频截屏图片进行了亮度和对比度调整,以消除光照的影响,其次进行消除运动模糊处理;采用数字图像相关（DIC）方法对矫正后的图像进行整像素搜索和亚像素拟合,使滑动前后的滑坡体互相匹配,求出了滑坡上各点的位移方向和大小,从而得到了整体下滑时段滑坡上所有点的位移分布图及其发展变化图像．计算结果表明,在开始滑动的8 s之内,坡体做为一个整体滑动由慢到快,当总体滑动位移量达到0.3 m的量级以后,滑坡迅速解体分散下滑．用该方法计算滑坡地表位移场及其变化过程不仅成本低、操作简便,而且可以清晰地描绘滑坡的位移过程以及尺度． 相似文献
9.
与滑坡变形相关的微震称作滑坡震,反映了滑坡上不稳定区域对外界环境因素的响应,分析滑坡体微震事件的地震学性质能够为理解滑坡的动力学过程、进行滑坡稳定性分析以及灾害防治提供关键信息。放置在滑坡上的地震仪不但能记录到和滑坡变形相关的微震,可能还会记录到一些人类活动信号。滑坡上的人类活动产生的震动事件给滑坡震探测带来挑战。梭坡滑坡位于四川省丹巴县大渡河左岸猴子岩水库库尾,是丹巴县古碉群的集中分布区之一,近年来滑坡灾害频发,其稳定性对古碉群保护和水库蓄水位的选择均十分重要。为监测该滑坡体局部破裂产生的微震信号,2017年2月至3月在滑坡上布设了34台三分量短周期地震仪。基于信号到时和波形特征确定几类模板事件,采用滑动时窗互相关的方法检测微震事件,并对信噪比较高的事件进行定位。根据事件的位置和到时信息,估算出滑坡体东西部浅层沉积层面波速度结构存在一定差异,表明了滑坡浅层沉积层物质分布的横向不均匀。根据这些事件的发生时间和波形特征,认为除了滑坡震,梭坡滑坡上还存在燃放烟花造成的震动事件。 相似文献
10.
11.
12.
In the experiments, a high-density resistivity method is used to explore the electric structure of landslip mass, and a resistivity-changing anisotropy method is used to monitor the orientation and speed of main fracture extending of landslip mass. The results are as follows. 1 The exploring experiments have verified a part of creep deformation borderline, the depth and thickness of groundwater horizon, and the property of superstrata in the landslip mass investigated formerly, which have proved that the landslip belts contain rich groundwater; 2 The main fracture extending orientation inferred from the resistivity-changing anisotropy accords with the strike of fracture belt of landslip mass deduced from GPS displacement. Moreover, the changing rates of resistivity-changing anisotropy coefficient matches with the changing speeds of deep displacement of landslip mass were measured by suing clinometer in the borehole. 相似文献
13.
Gennadiy V. Ryabinin Valeriy A. Gavrilov Yuriy S. Polyakov Serge F. Timashev 《Acta Geophysica》2012,60(3):874-893
We propose a new type of earthquake precursor based on the analysis of correlation dynamics between geophysical signals of
different nature. The precursor is found using a two-parameter cross-correlation function introduced within the framework
of flicker-noise spectroscopy, a general statistical physics approach to the analysis of time series. We consider an example
of cross-correlation analysis for water salinity time series, an integral characteristic of the chemical composition of groundwater,
and geoacoustic emissions recorded at the G-1 borehole on the Kamchatka peninsula in the time frame from 2001 to 2003, which
is characterized by a sequence of three groups of significant seismic events. We found that cross-correlation precursors took
place 27, 31, and 35 days ahead of the strongest earthquakes for each group of seismic events, respectively. At the same time,
precursory anomalies in the signals themselves were observed only in the geoacoustic emissions for one group of earthquakes. 相似文献
14.
15.
通过对甘肃中东部大量地震滑坡的成灾机制分析，按形成时代将滑坡分为新滑坡、老滑坡和古滑坡；按物质组成、滑体厚度及滑床位置又可分为浅层黄土滑坡和深层切层滑坡。该地区地震滑坡的主要危险来自新滑坡和浅层黄土滑坡，滑坡成灾机制复杂，与许多因素有关。地震滑坡主要特征是成灾时间短，规模大；灾害持续时间长、反复性大；易引发次生灾害。预防地震滑坡是防震减灾工作中的一项重要任务。 相似文献
16.
17.
John F. Hermance 《Physics of the Earth and Planetary Interiors》1973,7(3):349-364
The processing of magnetotelluric data involves concepts from electromagnetic theory, time series analysis and linear systems theory for reducing natural electric and magnetic field variations recorded at the earth's surface to forms suitable for studying the electrical properties of the earth's interior.The electromagnetic field relations lead to either a scalar transfer impedance which couples an electric component to an orthogonal magnetic component at the surface of a plane-layered earth, or a tensor transfer impedance which couples each electric component to both magnetic components in the vicinity of a lateral inhomogeneity.A number of time series spectral analysis methods can be used for estimating the complex spectral coefficients of the various field quantities. These in turn are used for estimating the nature of the transfer function or tensor impedance. For two dimensional situations, the tensor impedance can be rotated to determine the principal directions of the electrical structure.In general for real data, estimates of the apparent resistivity are more stable when calculated from the tensor elements rather than from simple orthogonal field ratios (Cagniard estimates), even when the fields are measured in the principal coordinates. 相似文献
18.
《Journal of Atmospheric and Solar》2003,65(5):561-566
Sprites were observed over Asian continent and over oceans around Taiwan in the summer of 2001 (Geophys. Res. Lett. 29(4) 2002). In this article, we report some characteristic differences between the oceanic and the land sprites. Qualitatively, the oceanic sprites are tended to be brighter than the land sprites. Also some of the oceanic sprites have very peculiar forms, which do not match any of the existing types. In two of the recorded sprites, the diffuse hair region contains a distinct short streak. We suspect that they probably are tracks left behind by micrometeorites, which might also have helped in lowering the threshold of the electric field needed for sprite generation and produced exceptionally bright sprites.For the optical survey, one of the observation sites was situated in the campus of the National Cheng Kung University, which is located at the center of the Tainan metropolitan area with more than one million residents. However, on June 7, 2001, we were able to recorded 6 oceanic sprites from this highly light-polluted site. Our experience exemplifies the exceptional brightness of the oceanic sprites. The Asian TLEs recorded in this survey were observed to occur above thunderstorms at stationary fronts and over localized thunderstorms. The sole attempt to observe TLEs over typhoon Chebi failed, hence, whether they exist over tropical storms in the Asian region is yet to be confirmed. 相似文献
19.
The diurnal-variation anomalies of the vertical-component in geomagnetic field are mainly the changes of phase and amplitude
before strong earthquakes. On the basis of data recorded by the network of geomagnetic observatories in China for many years,
the anomalous features of appearance time of the minima of diurnal variations (i.e, low-point time) of the geomagnetic vertical components and the variation of their spatial distribution (i.e, phenomena of low-point displacement) have been studied before over 30 strong earthquakes with M
S≥6.6 such as Kunlunshan M
S=8.1 earthquake on November 14, 2001; Bachu-Jashi M
S=6.8 earthquake on February 24, 2003; Xiaojin M
S=6.6 earthquake on September 22, 1989, etc. There are good relations between such rare phenomena of geomagnetic anomalies and the occurrence of earthquakes. It has
been found that most earthquakes occur in the vicinity of the boundary line of sudden change of the low-point displacement
and generally within four days before and after the 27th or 41st day counting from the day of appearance of the anomaly. In
addition, the anomalies of diurnal-variation amplitude near the epicentral area have been also studied before Kunlunshan M
S=8.1 earthquake and Bachu-Jiashi M
S=6.8 earthquake.
Foundation item: National Science Technology Tackle Key Project during the Tenth Five-year Plan (2001BA601B01-05-04) 相似文献
20.
研究了2001年11月14日昆仑山MS8.1大地震前新疆地区宽频带地震仪记录到的异常扰动事件.新疆地震台网在发生强震的前三天记录到了强烈的扰动信号.由于新疆地震台距离昆仑山大地震的震中很近,因此该震前扰动的成因备受关注,一直被认为可能是与大地震相关的慢地震事件,可能是大地震的某种前兆现象.本研究扩大了观测异常扰动事件的范围,分析了欧亚大陆187个宽频带地震仪在2001年11月的观测记录,发现这些地震仪在11月10—12日期间都记录到了时频特征类似的强扰动信号,其中最强的扰动信号出现在挪威台站KONO.调查研究发现挪威海域在11月10—12日期间出现了一次超强北极风暴,我们对扰动源位置初步定位后发现大地震前欧亚大陆各台站记录的最大扰动信号主要来源于挪威西南海岸.本文的研究结果确认昆仑山大地震前新疆台网记录到的强烈震前扰动信号不是与大地震相关的慢地震事件,而是挪威海域北极风暴激发的微地震（地脉动）.本文进一步研究表明北极风暴激发的地脉动可显著影响中国大陆的地震和重力观测.在分析中国大陆地震台网记录的强扰动信号时,北极风暴的影响不能忽视. 相似文献