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1.
R. T. Severn 《Bulletin of Earthquake Engineering》2012,10(2):351-366
This paper is an explanation of how earthquakes have been interpreted by our predecessors since written records began. Before
that we can only surmise that different societies had deities associated with mythological creatures able to cause earthquakes
on one pretext or another. Here I have used the Japanese catfish—or ‘namazu’—creature to a large extent, partly because it
is well-documented, but also because it is still used as a metaphor for earthquakes in official Japanese disaster prevention
activities. Both the Bible and the Koran explain that earthquakes are God’s punishment for committed sin, and this idea was
used until the seventeenth century, particularly by the Christian Church, in explaining their occurrence. The earliest rational
approach appears to have come from the founding of Scientific Societies in Europe, beginning in Naples in 1560 and followed
quickly by others in many European capital cities including London, where the Royal Society, founded in 1660, had the almost
unique benefit of knowledge about earthquakes brought to London by its trade with many parts of the known world. Its Fellows
had an opportunity to develop a more balanced approach, producing ideas which often centred on subterranean fire in the earth.
Even so, the notion that God was the immediate cause had not disappeared. The 1755 the Great Lisbon earthquake was a seismic
event in the religious and philosophical explanation of its cause. European philosophers, led by Leibnitz and Voltaire held
contrary views about God and the world, with the latter concluding that earthquakes were caused by natural events with an
unknown cause, about which the sins of the people had no influence. Rousseau was another philosopher of influence, initiating
the concept of risk, arguing that it was the actions of people which turned an event into a disaster. These philosophers had
the benefit of scientific knowledge about the world, originating with Copernicus and subsequently developed by those Scientific
Societies referred to above which were created as early as the sixteenth century. 相似文献
2.
水库地震由于具有震源浅、震级小但破坏较同等级的天然地震重的特点,其地震烈度衰减关系在水库地震灾害预测中有着十分重要的研究意义。然而,由于水库地震事件数量少,历史震例往往缺乏地面烈度调查资料,这给研究工作带来了相当大的难度。为了解决资料不足的问题,文中采用聚类分析的方法,从丰富的天然地震中选择可与水库地震灾害类比的震例,把其烈度资料引入衰减模型进行回归分析,得到了新的地震烈度衰减关系;并与已有的研究成果和天然地震的烈度衰减进行比较,证明了这种方法具有合理性,所得到的水库地震烈度在近场普遍比天然地震烈度高,但由于加入了天然地震资料使得结果比已有水库地震烈度衰减慢且震中烈度稍低 相似文献
3.
Prephotographic depictions of earthquakes can contain important information on the types and amount of damage due to a large earthquake in historic times. Care must be used in evaluating such depictions because some are more accurate than others, and many depictions contain little that is of value in making estimates of seismic intensity. Depictions of two earthquakes, in 1692 at Jamaica and in 1843 at Guadeloupe, illustrate the utility of depictions in intensity estimation. A depiction of the scene at Port Royal in Jamaica of the 1692 shock suggests that the major damage was caused by soil slumping and a tsunami, with the ground shaking itself probably only having been about MMI VII. Two depictions of Pointe-à-Pitre at Guadeloupe after the 1843 event contain evidence that the town was damaged by strong ground shaking as well as by major soil failures. The ground shaking here was probably MMI VII–IX. These and other pictures are being assembled for a monograph of prephotographic earthquake depictions in the Americas. 相似文献
4.
对我国近海海域有历史记载以来的地震的震级、震中参数进行了整理分析,并分析了各海域地震活动的时、空分布规律,根据历史地震资料,确定海域受历史地震影响的最大影响烈度,然后初步分析了地震活动与现代构造应力场、地球物理场的关系.研究发现:(1)近海海域历史地震资料的精度较低,中强地震存在明显的遗漏.(2)渤海、台湾海峡、南海北部地震活动性较强,黄海次之,东海最弱.(3)近海海域的震害主要来自海域地震和近岸陆地强震的影响,影响强弱依次为:渤海、黄海、东南沿海、东海.(4)现代构造应力场以水平向构造应力场作用下的走滑运动为主,最大主应力方向受印度板决和太平洋板块、菲律宾海板块的俯冲挤压方向影响.(5)海域地球物理场,特别是布格重力异常、地壳厚度分布与强震构造带的空间分布关系的相关性较好.本文的研究结果可为我国海域及滨海重要工程的抗震设防、海域地震危险性区划提供一定的基础. 相似文献
5.
We present a new strategy to estimate the geometry of a rupture on a finite fault for rapid reporting of seismic intensity. We use envelope attenuation relationships which were presented by Huo et al. (Acta Seismol Sin 16:519–525, 1994). An important base of this work is the fault finiteness theory. We propose a new model to simulate high-frequency motions from earthquakes with large rupture dimension. The envelope of high-frequency ground motion from a large earthquake can be expressed as a root-mean-squared combination of envelope functions from smaller earthquakes. We use simulated envelopes of ground acceleration to estimate the direction and along-strike length of a rupture. Using the Wenchuan and Jiji (Chi-Chi) earthquake dataset, we parameterize the fault geometry with an epicenter, a fault strike, and along-strike rupture lengths. So this methodology seems quite appropriate for the rapid reporting systems of seismic intensity. 相似文献
6.
采用现代仪器地震记录和烈度资料,我们建立了用于定量估算历史地震震级和震中位置的烈度衰减模型和分析方法,并对我国西南川滇地区的历史和近代地震的震中和震级进行了重新分析.利用20世纪以来该地区十四个有仪器记录的地震（5.9≤Ms≤8.0）及相应的烈度数据,对其烈度-震级-震中距衰减关系进行标定,并建立了用于震中和震级估算的烈度衰减模型.结果表明,当震级一定时,川滇地区烈度随震中距增大而衰减的速率明显小于美国加州地区（～60%）.在衰减模型基础之上,发展了确定震中区域和震级的网格搜索试算方法（GSTSL）,并给出了确定震中位置和震级的等值线置信值.采用所建立的分析方法,对1786年康定地震,1850年西昌地震,1913年峨山地震和1970年通海地震进行了分析,给出了更为精确合理的结果. 相似文献
7.
Susan E. Hough 《Bulletin of Earthquake Engineering》2014,12(1):135-155
Pioneering work by Nicolas Ambraseys and many collaborators demonstrates both the tremendous value of macroseismic data and the perils of its uncritical assessment. In numerous publications he shows that neglect of original sources and/or failure to appreciate the context of historical accounts, as well as use of unreliable indicators such as landsliding to determine intensities, commonly leads to inflated magnitude estimates for historical earthquakes. The U.S. Geological Survey “Did You Feel It?” (DYFI) system, which now collects and systematically interprets thousands of first-hand reports from felt earthquakes, provides the opportunity to explore further the biases associated with traditional intensity distributions determined from written (media or archival) accounts. I briefly summarize and further develop the results of Hough (2013), who shows that traditional intensity distributions imply more dramatic damage patterns than are documented by more spatially rich DYFI data, even when intensities are assigned according to the conservative practices established by Ambraseys’ work. I further consider the separate intensity–attenuation relations that have been developed to characterize intensities for historical and modern earthquakes in California, using traditionally assigned intensities and DYFI intensities, respectively. The results support the conclusion that traditionally assigned intensity values tend to be inflated by a fundamental bias towards reporting of dramatic rather than representative effects. I introduce an empirical correction-factor approach to correct for these biases. This allows the growing wealth of well-calibrated DYFI data to be used as calibration events in the analysis of historical earthquakes. 相似文献
8.
The seismic hazard of SW Iberia is composed of two contributions: offshore, large to very large events on the plate boundary between Africa and Eurasia such as the Lisbon earthquake of 1755 or the Gorringe Bank earthquake of 1969; and onshore, moderate to strong intraplate earthquakes on inherited crustal fractures. One of these zones of crustal weakness is the Lower Tagus Valley (LTV) fault zone, which displays the highest level of seismic hazard in Western Iberia. In this paper we review the active tectonics and seismicity of the LTV, integrating previous geophysical data with recent results of paleoseismological investigations, and discuss its impact on the seismic hazard of SW Iberia. We conclude that the seismic zonation for hazard assessment currently in force in the building code is biased towards the scenario of distant offshore rupture, and does not take adequately into account the LTV seismic source. 相似文献
9.
With the central part of Shanxi Province as an example, this paper studied seismic intensity zonation directly by use of the response intensity of historical earthquakes. From the result, some conclusions can be drawn as follows: (1) For areas rich in data of historical earthquakes, the seismic intensity zonation map with probabilistic meanings can be compiled by use of the statistical features of the response intensity of sites; (2) When determining the length of time for statistics, the completeness of response intensity data and the inhomogeneity of regional seismic activities should be fully considered; (3) By comparing the seismic intensity zonation result for recurrence interval of 500 years with the new Seismic Intensity Zonation Map of China (1990), it has been found that the two are roughly similar; though they are somewhat different for some localities, each has its own reasonableness. 相似文献
10.
随机方法在地震烈度速报中的应用 总被引：1，自引：0，他引：1
我国地震监测台网间距大,很难实现大震发生时地震烈度分布图的快速编制.基于随机方法,利用历史小震数据反演地震动估计模型的参数,参考地震发生时获取的少量强震动数据,选取合适的震源参数,正演地震动场的分布.根据地震烈度与地震动参数的经验关系,实现地震烈度速报.本方法可以模拟大震的近断层地震动特征,对高烈度区的判断较目前常用的烈度速报方法更为合理.研究成果既可以用于首张烈度分布图的发布,还能够用于地震烈度的动态修正. 相似文献
11.
中国西部地区地震烈度衰减关系 总被引：9，自引：4，他引：5
本文收集了1991年之后我国西部地区71个地震的烈度等震线资料,并以此对1918—1989年间176次地震的烈度资料进行了补充,采用长、短轴椭圆模型重新拟合了西部地区的分区地震烈度衰减关系。结果表明,新疆区和川藏区2个统计单元内地震烈度衰减关系有显著不同,应作为不同的分区对待。同时与其他研究者给出的该地区地震烈度衰减关系的对比结果显示,本文结果合理可靠,体现了近、远场地震烈度分布的特点,适合于该地区工程地震研究和应用。 相似文献
12.
With the central part of Shanxi Province as an example, this paper studied seismic intensity zonation directly by use of the
response intensity of historical earthquakes. From the result, some conclusions can be drawn as follows: (1) For areas rich
in data of historical earthquakes, the seismic intensity zonation map with probabilistic meanings can be compiled by use of
the statistical features of the response intensity of sites; (2) When determining the length of time for statistics, the completeness
of response intensity data and the inhomogeneity of regional seismic activities should be fully considered; (3) By comparing
the seismic intensity zonation result for recurrence interval of 500 years with the new Seismic Intensity Zonation Map of
China (1990), it has been found that the two are roughly similar; though they are somewhat different for some localities,
each has its own reasonableness.
Contribution No. 95A00095, Institute of Geophysics, SSB, China. 相似文献
13.
14.
China is the country with the challenge of severe earthquake disaster. In order to mitigate the disaster and save lives, emergency response and rescue work after an earthquake are deployed and led by the Chinese governments at all level, the effectiveness of which has been proved. In such work, how to quickly evaluate the seismic intensity in meizoseismal area is a crucial issue at the early period after the earthquake. It is the foundation to estimate the disaster losses and decide the scale of rescue teams and materials. However, at the early period only a few physical parameters of the earthquake can be acquired and some of them may even be inaccurate.
An evaluation model of seismic intensity in meizoseismal area is investigated and presented by statistic method in this study. After an earthquake there are four authoritative parameters officially released by China Earthquake Administration generally within ten minutes:earthquake magnitude (MS), focal depth, latitude and longitude position, and the occurrence time. They are good candidate input parameters of the evaluation model. We collect the information of 215 historical earthquake occurring in China from 1966 to 2013, including:The four parameters and the seismic intensity in meizoseismal area. Through statistical analysis we find the seismic intensity in meizoseismal area has high correlation with the earthquake magnitude (MS) and the focal depth and then select them as the formal input parameters. After further investigation a generalized linear model is built to fit the relationship between the seismic intensity in meizoseismal area, earthquake magnitude (MS) and the focal depth.
The effectiveness of the model is validated by the Sig value and F value from theoretic perspective. The validation also includes the application of the model in real earthquakes occurring from 2014 to 2017. After the earthquakes, the seismic intensities in meizoseismal area have been quickly estimated and used in the command of national earthquake disaster emergency relief. The applications in real earthquakes get good results.
Finally, the robustness of the model is analyzed. We respectively verify the influences of the earthquake magnitude (MS) and the focal depth and find the seismic intensity in meizoseismal area is more sensitive to the earthquake magnitude. Under the condition of the same focal depth, when the change of the earthquake magnitude is up to 0.5, the change of the seismic intensity will reach to 1. However, in order to cause same change of the seismic intensity, the difference of the focal depth will be 10 kilometers. Basically, these changes derived from the model meet the situation of historical earthquakes. 相似文献
15.
L. Sirovich 《Soil Dynamics and Earthquake Engineering》1997,16(6):353-362
Recent tests on a series of earthquakes in California and Nevada suggest that in some regions the approximate shapes of the territories with equal earthquake-induced damage (expressed in terms of macroseismic intensity) could be synthetically traced out with a simple formula. This formula takes into account some gross features of the source: depth and length, unilateral or bilateral rupture, radiation patterns, rupture velocity, and directivity. Having been formulated on an empirical basis, the formula is however compatible with the so-called asymptotic approach, in which the far-field component of the Green's function is used. This paper presents the synthetic isoseismals of the earthquakes at Cedar Mountain, Nevada, 1932; Fairview Peak-Dixie Valley, Nevada, 1954; and Coalinga, California, 1983. An overall consistency, from acceptable to remarkable, between the observed intensity patterns and the synthetically back-predicted intensity has been obtained for them. Where the detailed modelling techniques available today are inapplicable, due to insufficient information on the features of the seismic sources, or to save time and money, the new formula may be utilizable for improving seismic hazard calculations.The formula was also used inversely for back-predicting geometric-kinematic parameters of the Coalinga 1983 earthquake from macroseismic maps. This gave characteristics for its source which are in good agreement with the majority of data inferred from modelling and from analyzing modern instrumental recordings. This striking result opens new perspectives in retrieving information on the source of ancient earthquakes for which only macroseismic information is available. 相似文献
16.
本文通过对1976年唐山地震及其7.1级强余震宏观现象的分析,指出强震引起地面运动及建筑物的倒塌具有一定的优势方向。但同一地区不同强震引起的地面运动及建筑物的倒塌方向常不相同。发现强震高烈度区存在许多震害轻重相间的异常条带,其延伸方向大体上与地震断层平行。这种规律,给地震危险区内的各类工程、土木建筑的抗震设计提供了一些新的依据。 相似文献
17.
While rockbursts from underground copper mining in Western Poland normally produce surface peak ground accelerations (PGA) and velocities of 0.05–0.1 g and 1–3 cm/s, occasionally these peak motions may exceed 0.15 g and 10 cm/s, respectively. These larger motions are of considerable concern and an investigation has been undertaken to define the nature of these larger induced ground motions. This paper compares these rockburst motions with low intensity earthquakes. Various strong motion parameters such as PGA, peak ground velocity (PGV) and displacements as well as strong motion duration, Arias intensity, Fourier and response spectra are compared with those from earthquakes. It is concluded that although short duration is the most obvious parameter that differentiates rockbursts from earthquakes, in fact their high dominant frequencies, which result in high PGA/PGV ratios differentiate them the most. Two types of rockburst-induced ground motions are indicated in this paper: typical—with 3–6 months return period and characteristic, high frequency content—as well as rare events similar to shallow, low intensity earthquakes. 相似文献
18.
双塔连体结构弹塑性时程分析 总被引：1，自引：0，他引：1
双塔连体结构是我国实际工程中应用越来越多的一种结构形式.该结构形式是在两塔楼顶部设置连体部分的新型建筑结构形式.本文针对某一连体结构,采用NosaCAD有限元软件建立整体结构分析模型.通过建立模型,分析结构在7度多遇和罕遇地震下的弹塑性时程反应,得到结构在地震作用下的变形、内力和破坏情况的变化过程.结果表明,小震情况下... 相似文献
19.
A database of intensity observations from instrumentally recorded earthquakes in South Africa has been compiled as a contribution to the characterisation of seismic hazard. The database contains about 1,000 intensity data points (IDPs) that have been assigned from macroseismic observations retrieved from newspaper reports and questionnaires, and also digitised from previously published isoseismal maps. The database includes IDPs from 57 earthquakes with magnitudes in the range of M w 2.2 to 6.4, at epicentral distances up to 1,000 km. Sixteen events have 20 or more IDPs, with half of these events having more than 80 IDPs. The database is dominated by relatively low intensity values, mostly determined from human perception of shaking rather than structural damage. However, 19 IDPs correspond to intensity values greater than VI MMI-56. Using geological maps of South Africa, the sites of 60 % the IDPs were geologically classified as either ‘rock’ or ‘soil’, the uncertainty in locations precluding such a classification for the remaining data points. A few of the IDPs identified as being from soil sites appear to be strongly influenced by site effects, and these were removed from the trimmed database created for exploring ground-motion levels. The trimmed database includes 15 earthquakes which have a minimum of five useful IDPs, excluding those with intensity MMI?=?I and those based on a single observation. After removing such points, and those identified as clear ‘outliers’, a total of 436 useful IDPs were selected. 相似文献
20.
Influenced by the layout of seismic network and the location of earthquakes, earthquake catalogs are often incomplete; such incompleteness of earthquake catalogue directly affects the analysis of sequence activity characteristics. In this paper, the GPU-acceleration-based g template matching method is used to scan the continuous waveforms of Chang Island earthquake swarm in Shandong Province from February 9 to August 20, 2017. In total, 15,286 earthquakes events were detected, which was more than 6 times compared with those in network catalogue and thus reduced the magnitude of completeness from 1.0 to 0.5. Based on the intergrated catalogue of earthquakes, the characteristics of Chang Island earthquake swarm were then analyzed using the Epidemic Type Aftershock Sequences (ETAS) model. The stochastic components in the ETAS model are used as a proxy for possible earthquake triggered by external forces (fluids). The results show that the proportion of earthquakes triggered by external forces of Chang Island swarm increases gradually (from 31.9% to 63.5%) and then decreases. The latter stage of swarm development is mainly affected by the self-excitation of earthquakes,suggesting that the fluids play an important role in the development of the Chang Island swarm. However, the triggering intensity of fluids to microseismicity is divergent in different periods, which may be related to the process of fluid permeation. 相似文献