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1.
We developed a recipe for predicting strong ground motions based on a characterization of the source model for future crustal earthquakes. From recent developments of waveform inversion of strong motion data used to estimate the rupture process, we have inferred that strong ground motion is primarily related to the slip heterogeneity inside the source rather than average slip in the entire rupture area. Asperities are characterized as regions that have large slip relative to the average slip on the rupture area. The asperity areas, as well as the total rupture area, scale with seismic moment. We determined that the areas of strong motion generation approximately coincide with the asperity areas. Based on the scaling relationships, the deductive source model for the prediction of strong ground motions is characterized by three kinds of parameters: outer, inner, and extra fault parameters. The outer fault parameters are defined as entire rupture area and total seismic moment. The inner fault parameters are defined as slip heterogeneity inside the source, area of asperities, and stress drop on each asperity based on the multiple-asperity model. The pattern of rupture nucleation and termination are the extra fault parameters that are related to geomorphology of active faults. We have examined the validity of the earthquake sources constructed by our recipe by comparing simulated and observed ground motions from recent inland crustal earthquakes, such as the 1995 Kobe and 2005 Fukuoka earthquakes. 相似文献
2.
基于震源动力学模型,采用曲线网格有限差分法模拟了水平自由地表及实际地形条件下2010年玉树MS7.1地震的震源破裂过程及相应的地面地震动,获取了断层面上的破裂传播过程、最终滑移量分布及峰值地面速度分布,讨论了实际地形对玉树地震破裂过程及相应地震动的影响。基于本文设定的动力学模型,模拟结果显示:断层面上的高应力降是玉树地震出现超剪切破裂传播现象的主要原因;计算区域的实际地形阻碍了由自由地表引起的超剪切破裂的产生,对断层面滑移量的分布特征及滑动速率影响较大,进而在一定程度上降低了地震动峰值,同时对地震动的分布特征产生影响,且地震动平行断层面的水平分量相对受影响更大。 相似文献
3.
基于第四代地震区划的跨越发震断层永久位移概率分析方法 总被引：2，自引：1，他引：1
本文主要借鉴了Lee(2007)和Youngs(2003)提出的地表永久位移估计方法,联合中国第四代地震区划图的潜在震源区参数,给出了适合中国跨越发震断层永久位移概率分析方法。震害调查表明,近场的结构破坏不仅是地震动引起的,地震地表的破裂或永久位移引起的破坏也占很大比重。应用与概率估计地震动相似的方法,给出不同概率水准的地震地表永久位移,使之服务于穿越地震发震断层管线、桥梁工程的抗震设防,采取有效的抗御永久地表位移措施,减小地震灾害带来的损失。 相似文献
4.
2021年5月22日青海省玛多县发生Mw7.3级地震。震后,根据初步估计的断层走向和破裂长度,基于YU15地震动衰减模型和三种NGA-West2（Next Generation Attenuation-West2）地震动衰减模型快速产出地震区震动图及理论烈度图。在获得强震记录和地表破裂长度信息后,对预测结果进行修正。通过比较理论烈度与调查烈度,并结合震动图分布形态以及衰减模型在2016年新疆呼图壁Mw6.0地震中的应用情况对四种地震动衰减模型的适用性进行了分析。结果表明:在台网稀疏地区,基于地震动衰减模型可在震后快速获得地震动分布,并产出具有应用价值的地震影响场;NGA-West2模型在断层破裂较长的大震中表现优于YU15模型,而在中强地震中后者适用性更强;近实时强震动记录可用来检验模型的适用性并对预测结果进行修正;断层破裂尺度、震源机制和破裂过程等信息的准确估计可有效提高地震影响场预测精度。 相似文献
5.
Characterization of Earthquake Strong Ground Motion 总被引：1，自引：0，他引：1
— Some underwater landslides are triggered by strong ground motions caused by earthquakes. This paper reviews current concepts and trends in the characterization of strong ground motion. Improved empirical ground motion models have been derived from a strong motion data set that has grown markedly over the past decade. However, these empirical models have a large degree of uncertainty because the magnitude-distance-soil category parameterization of these models often oversimplifies reality. This reflects the fact that other conditions that are known to have an important influence on strong ground motions, such as near-fault rupture directivity effects, crustal waveguide effects, and basin response effects, are not treated as parameters of these simple models. Numerical ground motion models based on seismological theory that include these additional effects have been developed and extensively validated against recorded ground motions, and used to estimate the ground motions of past earthquakes and predict the ground motions of future scenario earthquakes. 相似文献
6.
地震破裂区是地震时沿发震断裂带的同震错动面或破裂面在地表的垂直投影区域,指示了震源断层/破裂的位置与尺度。确定过去长期的强震/大地震破裂区是鉴别地震空区、研究与预测强震危险性的重要基础。对于现代强震,破裂区可运用多种现代技术方法确定,但对于历史强震,破裂区确定的方法需要探索与发展。以华北地区为例,研究利用烈度/等震线资料、结合地震构造与震区地表地质环境等信息确定历史强震破裂区的方法,并开展应用试验。结果表明:研究区现代地震破裂区延伸的烈度区间与极震区烈度、震区环境之间存在密切关系,基于这种关系建立了2条经验准则,可分别用于根据烈度分布确定华北2类震区环境(基岩区和厚层第四纪松散堆积覆盖区)历史强震破裂区的位置与延伸。文中还提出通过综合地震构造、现代小震/余震分布等信息,辅助确定历史强震破裂区横向宽度的思路与途径。作为应用试验,文中确定了5次历史地震的破裂区,结果表明本文发展的经验准则及相应方法适用于华北地区历史强震破裂区的确定。 相似文献
7.
Depths of earthquake occurrence and large slip distribution are critical for seismic hazard assessment.Numerous examples show that earthquakes with similar magnitudes,however,can result in significantly different ground shaking and damage.One of the critical factors is that whether the large slip was generated near the ground surface.In this article,we reviewed two aspects that are important on this regard,shallow slip deficit and nucleation depth.Understanding how shallow future earthquakes may nucleate in particular regions,such as shale gas fields,is critical for hazard assessment.Whether or not a strong earthquake may slip significantly at shallow depths(less than 3 km)plays crucial rules in seismic hazard preparation and should be further investigated by integrating high-resolution fault zone observations,dynamic rupture simulation,and fault zone properties.Moreover,precisely resolving shallow depth and slip distribution of earthquakes demands InSAR and/or other image data that can better capture the near-fault deformation to constrain the source parameters of earthquakes. 相似文献
8.
隐伏和出露地表断层近断层地表运动特征的研究进展 总被引：2，自引：1，他引：1
本文介绍了在强震地震学研究方面国内外目前所关注的重要问题：隐伏断层和出露地表断层在地震发生时近断层地表运动特征存在着明显的差异。根据近几十年全球发生的中强地震的地表运动参数的统计分析所得的结果表明,由隐伏断层所造成的近断层地表运动强度（速度、加速度）大于出露地表断层所产生的地表运动强度,虽然发生在出露地表断层的地震往往可造成较大的近断层地表位移,但是当地震矩震级（MW）达到 7.5 级以上的时候,近断层地表加速度和速度在近源区却出现了饱和现象。对该问题的深入研究有着十分重要的科学意义和工程应用价值。本文着重介绍了当前国际上对该问题的研究现状,并且建议在此基础上利用三维有限差分断层动力学模型,模拟断层的动态破裂过程以及近断层地表运动的特征。 相似文献
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鲜水河断裂的几何形态对地震发生的影响 总被引：2，自引：2，他引：0
本文整理分析了鲜水河断裂的几何特征以及从1327年有记录以来6级以上历史地震的断层破裂位置和长度。选用速率和状态依赖性摩擦本构关系代表断裂区域物理性质,构建了鲜水河断裂3D物理模型模拟强震周期性。模拟结果与历史地震的发震有较好的一致性,主要表现在:1模拟结果在第二次地震周期之后,明显出现分段现象与鲜水河断裂分段的几何特征较为一致;2断裂北西端结构较为简单,地震发震情况也偏单一,在7级以上地震发震之前有6级以上地震的发生,此类现象与模拟结果一致;3断裂中段结构复杂,不仅存在分段还有轻度弯曲,模拟结果显示中段地震逐渐减小,破裂长度逐步缩短,并且出现级联破裂现象与历史地震较为吻合;43D模拟结果中,地震破裂区域起始与终止位置大都发生在断层转折的区域,特别是在乾宁和康定两处断层出现弯曲的位置,这与鲜水河断裂历史地震发震情况十分相似。 相似文献
10.
Characteristics of amplitude and duration for near fault strong ground motion from the 1999 Chi-Chi, Taiwan Earthquake 总被引：2，自引：0，他引：2
A great number of free-field ground motion records are obtained during the 1999 Chi-Chi, Taiwan, earthquake. Records from 130 near fault free-field stations within 55 km to the causative fault surface are used as database, and characteristics of earthquake peak ground acceleration, velocity, displacement and duration are analyzed. According to this study, near fault ground motions are strongly affected by distance to fault, fault rupture directivity, site condition, as well as thrust of hanging wall. Compared with empirical strong ground motion attenuation relations used in China, US and Japan, the PGAs and PGVs recorded in this earthquake are not as large as what we have expected for a large earthquake as magnitude 7.6. However, the largest PGV and PGD worldwide were recorded in this event, which are 292 cm/s and 867 cm, respectively. Caused by nonlinear site effects of soil, peaks and corresponding ratios on E-class site were markedly different from those on other sites. Just as observed in historic earthquakes, fault rupture directivity effects caused significant differences between peaks of ground motion of two horizontal components, but took very slight effects on the duration of ground motion. The significant velocity pulses associated with large PGVs and PGDs, as well as large permanent displacements, which may result from the large thrust of the hanging wall, became the outstanding character of this event. Based on this study, we point out that 3D waveform modeling is needed to understand and predict near fault ground motion of large earthquakes. 相似文献
11.
强烈地震震源区和其周边地域的介质,在力源作用下开始破裂,即微破裂,而当其在应力不断积累、逐渐发展并形成具有一定规模的“破裂链”时,即应力集中达到临界状态时,震源介质所积累的巨大能量以波动的形式瞬间释放,并冲出地表发生地震,且在地表产生一系列的破坏和大型断裂.在强烈地震发生后依据设定的初始模型和远、近地震台网记录,通过震源机制解计算,可求得震源介质的破裂长度和破裂过程.事实表明,一系列大地震的“孕育”、发生和发展,由震源深处到地表均呈现出强烈的破裂效应,其破裂长度可由几公里、几十公里、乃至千余公里长.有的地震在发生前确亦存在着破裂响应和迹象.为此,若在地表和深井中能进行破裂效应的观测,以捕捉初始微破裂和其形成“破裂链”的动力过程,这对于短临地震预测可能是一个十分重要的途径. 相似文献
12.
A seismological overview of long-period ground motion 总被引：1，自引：1，他引：0
Long-period ground motion has become an increasingly important consideration because of the recent rapid increase in the number
of large-scale structures, such as high-rise buildings and oil storage tanks. Large subduction-zone earthquakes and moderate
to large crustal earthquakes can generate far-source long-period ground motions in distant sedimentary basins with the help
of path effects. Near-fault long-period ground motions are generated, for the most part, by the source effects of forward
rupture directivity. Far-source long-period ground motions consist primarily of surface waves with longer durations than near-fault
long-period ground motions. They were first recognized in the seismograms of the 1968 Tokachi-oki and 1966 Parkfield earthquakes,
and their identification has been applied to the 1964 Niigata earthquake and earlier earthquakes. Even if there is no seismogram,
we can identify far-source long-period ground motions through the investigation of tank damage by liquid sloshing. 相似文献
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Bounding of near-fault ground motion based on radiated seismic energy with a consideration of fault frictional mechanisms 
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下载免费PDF全文 The energy radiated as seismic waves strongly depends on the fault rupture process associated with rupture speed and dynamic frictional mechanisms involved in the fault slip motion.Following McGarr and Fletcher approach,we derived a physics-based relationship of the weighted average fault slip velocity vs apparent stress,rupture speed and static stress drop based on a dynamic circular fault model.The resultant function can be approximately used to bound near-fault ground motion and seismic energy associated with near-fault coseismic deformation.Fault frictional overshoot and undershoot mechanisms governed by a simple slip-weakening constitutive relation are included in our consideration by using dynamic rupture models named as M-and D-models and proposed by Madariaga(1976) and Boatwright.We applied the above function to the 2008 great Wenchuan earthquake and the 1999 Jiji(Chi-Chi) earthquake to infer the near-fault ground motion called slip weighted average particle velocity and obtained that such model-dependent prediction of weighted average ground velocities is consistent to the results derived from the near-fault strong motion observations.Moreover,we compared our results with the results by McGarr and Fletcher approach,and we found that the values of the weighted average particle velocities we obtained for these two earthquakes are generally smaller and closer to the values by direct integration of strong motion recordings of the near-fault particle velocity waveform data.In other words,if this result comes to be true,it would be a straightforward way used to constrain the near-fault ground motion or to estimate source parameters such as rupture speed,static and dynamic stress drops. 相似文献
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Over the past few decades, earthquake engineering research mainly focused on the effects of strong seismicshaking. After the 1999 earthquakes in Turkey and Taiwan, and thanks to numerous cases where fault rupture causedsubstantial damage to structures, the importance of faulting-induced deformation has re-emerged. This paper, along withits companion (Part Ⅱ), exploits parametric results of finite element analyses and centrifuge model testing in developing afour-step semi-analytical approach for analysis of dip-slip (normal and thrust) fault rupture propagation through sand, itsemergence on the ground surface, and its interaction with raft foundations. The present paper (Part Ⅰ) focuses on the effectsof faulting in the absence of a structure (i.e., in the free-field). The semi-analytical approach comprises two-steps: the firstdeals with the rupture path and the estimation of the location of fault outcropping, and the second with the tectonically-induced displacement profile at the ground surface. In both cases, simple mechanical analogues are used to derive simplifiedsemi-analytical expressions. Centrifuge model test data, in combination with parametric results from nonlinear finite elementanalyses, are utilized for model calibration. The derived semi-analytical expressions are shown to compare reasonably wellwith more rigorous experimental and theoretical data, thus providing a useful tool for a first estimation of near-fault seismichazard. 相似文献
17.
利用汶川地震区不同地段的断层围陷波记录,分析了该地震断层的分段性特征。对断层北东段的关庄测线分析研究结果表明：地壳内破碎带的宽度大约160~180m,地下破碎带的中间与地表破裂的位置对应,并且地下破碎带在断层的两盘边缘较均匀地分布,反映了北东段的断层倾角较陡,近似直立断层。对断层南西段的虹口测线研究结果表明：地壳内破碎带的宽度大约180~200m,地下破碎带主要分布在地表断层陡坎上盘所对应的地壳内,反映了南西段断层倾角比北东段断层倾角小。本文的研究结果可以为汶川8.0级地震的构造背景研究提供依据。 相似文献
18.
Wave energy flow in shallow ground depth is calculated based on main shock records obtained at 30 vertical array sites throughout Japan during nine recent strong earthquakes (MJ=6.4–8.0) by assuming vertical propagation of SH waves. It is generally found that upward energy tends to decrease considerably as it goes up from the base (about 100 m deep) to the ground surface. Large energy is reflected at layer boundaries with clear impedance contrast and returns to deeper ground, so that only less than 10–30% of the upward energy at the base level arrives at the ground surface in most sites. Energy dissipation calculated from the upward and downward energies tends to increase with the increase of damping ratio of the ground back-calculated from the seismic records. It is also found that the upward energy at the base may roughly be estimated for engineering purposes using spherical energy radiation of the body wave despite strong effects of fault rupture/path mechanisms. 相似文献
19.
对海域地震区划中涉及的我国海域有影响的俯冲带地震动参数预测模型研究进展与阶段性成果进行介绍,基于资料、回归方法等,对地震动参数预测模型建立过程进行说明。依托可靠的强震加速度记录与宽频带速度记录,采用使结果更稳定的分步回归方法,考虑俯冲带深大地震断层尺度与震源深度影响选取新的预测模型。针对我国海域实际地震环境,新的预测模型重点关注了对俯冲带长周期地震动的估计。 相似文献
20.
Qilian Shan-Hexi Corridor is located at the northeastern margin of Tibetan plateau. Series of late Quaternary active faults are developed in this region. A number of strong earthquakes even large earthquakes occurred in history and present-day. In the past, the study of active faults in the area was mostly concentrated in the northern margin fault zone of the Qilian Shan on the south side of the corridor, while the research on the interior and the north side of the corridor basin was relatively rare. We found a new fault scarp in the northern part of the Baiyanghe anticline in Jiuxi Basin in 2010. It is an earthquake surface rupture zone which has never been reported before. In this paper, we carried out palaeoearthquake trench analysis on the newly found earthquake surface rupture zone and textual research of relevant historical earthquakes data.
According to the interpretation of aerial photo and satellite image and field investigation, we found the surface rupture has the length of about 5km. The rupture shows as an arc-shaped line and is preserved intact comparably. The lower terrace and the latest flood alluvial fan are offset in addition to modern gullies. By differential GPS measurement, the height of the scarp is about 0.5~0.7m in the latest alluvial fan and about 1.5m in the T1 terrace. From the residual ruins along the earthquake rupture zone, we believe the surface rupture might be produced by an earthquake event occurring not long ago. In addition, the rupture zone locates in the area where the climate is dry and rainless and there are no human activities induced damages. These all provide an objective condition for the preservation of the rupture zone. The trench along the fault reveals that the surface rupture was formed about 1500 years ago, and another earthquake event might have happened before it. Based on the textural research on the historical earthquake data and the research degree in the area at present, we believe that the surface rupture is related to the Yumen earthquake in 365, Yumen Huihuipu earthquake in 1785 or another unrecorded historical earthquake event. 相似文献