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1.
John Antonopoulos 《Natural Hazards》1984,5(1):83-93
In 427 BC, a major earthquake occurred in ancient Greece. In particular, Attica, Boeotia, and the island of Euboea were the areas where seismic activity was most frequent. The fact that these events happened in conjuction with the Peloponnesian war provides us with an account made by historians of the war. Such an account is the one made by Thucydides.During the spring and summer of 426 BC shocks continued to take place. This time, the sea area between the island of Euboea and the mainland (Maliakos gulf) was also affected and as a result, a seismic sea-wave of considerable size formed. The tsunami, as it is better known, swept the surrounding coastal area. Major topographic alteration of the area occurred, resulting in a huge loss of life and the destruction of cities.In this paper, the author attempts to describe this event and to explain scientifically how it happened, and how this affected the shape of the area and human life.All the evidence used in this paper has been cross-referenced with at least one other historic or scientific source. Although it was extremely difficult to uncover hidden detail about an event so far in the past, any facts that could not be verified have not been included. 相似文献
2.
本文利用半经验、半理论的方法对世界各主要地震汇集和研究机构所给出的集集主震基本震源参数进行了综合计算和评定。根据这些参数重新计算了集集主震的标量地震矩、破裂面积、应力降等。根据这些参数之间的内在联系 ,从地震分类学的角度 ,判定集集地震是发生于板块边缘的大地震。可供研究台湾岛上地震活动性以及台湾地区板块构造演化问题参考。 相似文献
3.
本文利用半经验、半理论的方法对世界各主要地震汇集和研究机构所给出的集集主震基本震源参数进行了综合计算和评定。根据这些参数重新计算了集集主震的标量地震矩、破裂面积、应力降等。根据这些参数之间的内在联系,从地震分类学的角度,判定集集地震是发生于板块边缘的大地震。可供研究台湾岛上地震活动性以及台湾地区板块构造演化问题参考。 相似文献
4.
阿尔金断裂系东北段阳关断裂的晚第四纪活动性与强震危险性关系到敦煌地区及相关文物古迹的防震减灾问题.基于高分辨率卫星影像对阳关断裂几何展布特征进行解译,采用差分GPS、无人机航空摄影测量方法、古地震探槽方法以及OSL测年方法对两个研究点进行了详细研究,对其定量活动参数进行了初步限定.结果显示,阳关断裂东段运动形式主要表现为挤压逆冲,最新的一次地震事件可能发生在距今43.5~12.1 ka之间,表明阳关断裂东段至少在晚更新世以来有过活动,并且具有发生Mw6.6强震的潜能及危险性.如果发生类似强度的地震,敦煌主城区的烈度至少在Ⅵ以上,阳关土遗址地区则会达到Ⅸ.因此,阳关断裂应该是该区防震减灾重点关注的发震断层之一. 相似文献
5.
滩海区人工岛场地地震安全性评价 总被引：2，自引：1，他引：1
本文以辽河口滩海区人工岛场地为例, 从区域地震地质、近场区地震地质、区域地震活动等方面, 讨论了滩海区人工岛基本地震地质环境特点, 在此基础上, 完成场地地震烈度、地震设防参数、场地地震地质灾害等影响人工岛场地安全性的因素评价。结果说明, 从场地地震安全性角度, 本文所评价的场地, 对人工岛兴建是适宜的。 相似文献
6.
An earthquake of local magnitude 5.3 (duration magnitudeM
d
) on the Richter Scale occurred at Dahshour, 18 km south of Cairo, Egypt, on Monday, 12 October 1992 at 3:09 pm (local time). Numerous aftershocks followed the main event during the following weeks with magnitude up to 4.3. The earthquake occurred in an area that has had no recent seismic activity, and affected many cities in Egypt. Many buildings and monuments were severely damaged or collapsed. Modern concrete skeletal structures suffered minor nonstructural damage. Earthquake physical damage was estimated at about one billion U.S. Dollars. The severity of the damage was mainly due to poor construction materials and detailing, aging, inferior workmanship, and inadequate maintenance. Egypt was generally considered to be an area of moderate seismic activity. In 1989, earthquake provisions were first introduced in the Egyptian Code of Practice for Reinforced Concrete Structures only. The earthquake clearly showed the urgent need for an assessment and rehabilitation program to mitigate seismic risk hazard in existing structures. In addition, future development planning, and earthquake preparedness strategies should implement lessons learned from the event. In this paper, an overview discussion about the observations from the 12 October earthquake is presented. 相似文献
7.
A method for the evaluation of seismic hazard in a given zone, taking into account both the spreading of macroseismic effects and seismic catalogue information, is applied. A data-bank of some 500 digitized isoseisms of earthquakes having occurred in Italy between 1542 and 1986 is used. The isoseismical maps are digitized considering for each degree of intensity the length of 24 spreading rays starting from the macroseismic epicenter or barycentre of the megaseismic area. These rays are separated from each other by the same angle, i.e. every isoseism is divided into 24 equal circular sectors. The year 1542 is taken as the beginning of the time span, since this is when the first seismic event occurred for which reliable isoseismal maps are available. The epicentral intensities considered lie between theVI andXI degrees of the Mercalli-Cancani-Sieberg scale (MCS). This digitized data-bank is analyzed to achieve, for each homogeneous seismogenetic zone that has been recognized, the mean azimuthal spreadings of effects for each degree of intensity as a function of the epicentral intensity. Once a mean propagation model is obtained for each zone, this is applied to seismic events of the same zone, the isoseismal maps of which are not available. A geographic grid is defined to cover the analyzed area, and for each cell of this grid it is then possible to count the number of felt events and their degree. These effects have been evaluated either on the basis of the isoseismal maps (when available) or on the basis of the mean propagations of the zone in which the single event occurred. Moreover, an index summarizing the seismic information was computed for each cell of the previous grid. All the events producing effects and their provenance are stored on files, allowing the main seismogenic zones influencing this cell to be identified. This methodology has been applied to central and southern Italy in an area between the latitudes 40.6 and 43.3 N. In particular, attention is focussed on the sample areas of Rome (given the historical and political importance of the city) and of the Sannio-Matese and Irpinia zone (in which some of the strongest earthquakes of the Apennine chain have occurred). Finally, in order to evaluate the maximum expected magnitude, extreme value statistics (Gumbel III-type) are applied to the Colli Albani area, which represents the seismogenic zone nearest to Rome. For the Sannio-Matese and Irpinia area, considering the more dangerous zone as a ‘unicum’, theWeibull distribution has been hypothesized to determine the mean return time for events with an intensity greater than or equal to IX. 相似文献
8.
采矿塌陷在开采施工中被给予了特别关注,也是施工地质灾害重要表现形式之一。已有地震记录中不乏对其形态辨识,然而少见对塌陷机理和发生过程中能量转换等较全面的研究。温岭市长屿硐天采矿遗址区碧玉潭洞室群1997年8月11日早晨发生持续时间约20 s大塌方。现场残留了面积约31 380 m2、体积约1.35×106 m3的塌陷岩体。通过现场工程地质调查、塌陷过程追溯、邻近地震台站频谱记录分析,笔者认为这次发生在凝灰岩中的大规模塌陷系因地下采石过程中保安矿柱被过量开挖掉而引发局部顶板破裂和应力分布的大改变,进而发展至整个矿区岩体塌落破坏,使矿坑积水飞溅和压缩空气冲击波带来了沿途150 m范围内人员伤亡、树木折断和财产损失。塌陷区南93 km的温州台地震波谱记录了这次采矿塌陷地震活动,其波形数据与现场塌陷破坏能量转化情况基本吻合。在采矿活动中保安矿柱的合理配置、为人员安全设置变形破坏过程监测等,是需考虑的预防塌陷措施。 相似文献
9.
A number of high-profile seismic events have occurred in recent years, with a wide variation in the resulting economic damage and loss of life. This variation has been attributed in part to the stringency of seismic building codes implemented in different regions. Using the HAZUS Earthquake Model, a benefit?Ccost analysis was performed on varying levels of standard buildings codes for Haiti and Puerto Rico. The methodology computes expected loss assuming a Poisson event process with lognormally distributed event magnitude and idealized damage?Cmagnitude response functions. The event frequency and magnitude distributions are estimated from the historical record, while the damage functions are fit using HAZUS simulation results for events with systematically varying magnitudes and different seismic code levels. To validate the approach, a single-event analysis was conducted using alternative building codes and mean magnitude earthquakes. A probabilistic analysis was then used to evaluate the long-term expected value for alternative levels of building codes. To account for the relationship between lives saved and economic loss, the implicit cost of saving a life is computed for each code option. It was found that in the two areas studied, the expected loss of life was reduced the most by use of high seismic building code levels, but lower levels of seismic building code were more cost-effective when considering only building damages and the costs for code implementation. The methodology presented is meant to provide a basic framework for the future development of an economic-behavioral model for code adoption. 相似文献
10.
The catastrophic 1883 earthquake at the island of Ischia (southern Italy): macroseismic data and the role of geological conditions 总被引：1，自引：0，他引：1
This article presents the results of a detailed study of the effects of the 1883 earthquake, which occurred at the island
of Ischia (Gulf of Naples) and produced the total destruction of buildings in the epicentral area (Casamicciola town). Despite
the moderate magnitude, this event was characterised by very high intensities (I
max = XI degree MCS) mainly due to the shallow depth of the source. The study of the earthquake shows that the intensities, which
decreased rapidly with distance, were affected by source directivity, according to the causative fault geometry and tectonic
structures, while local amplification of damage was observed where soft soils outcrop. The attenuation of seismic intensity
with distance was evaluated using the well-known relation of intensity versus epicentral distance (Blake’s method). The diverse
gradients of attenuation, observed in different directions, were ascribed to the various geological features of the shallow
crust of the island. In order to evaluate the role of geology in the damage level, we computed different attenuation models
for stiff and soft soils outcropping on the island. A systematic local amplification of about 1 MCS degree associated to the
presence of reworked tuffs was obtained. This study also shows the influence of geological conditions on the evaluation of
macroseismic data and supplies useful elements to derive a predictive map of potential site effects. 相似文献
11.
Seismological, geological and geophysical constraints for the Gualdo Tadino fault, Umbria–Marche Apennines (central Italy) 总被引：1，自引：0，他引：1
The April 3, 1998 Mw = 5.1 Gualdo Tadino earthquake (central Italy) was the last significant event in the 6-month-long Umbria–Marche seismic crisis. This event and its aftershocks occurred in an area where active faulting produces no striking geological and geomorphological effects. In this study, we investigated the ruptured fault using detailed seismological data and a re-processed and re-interpreted seismic reflection profile. Aftershock location and focal mechanisms were used to constrain the geometry and kinematics of the ruptured fault and a comparison was made with the subsurface image provided by the seismic profile. We found that the 1998 Gualdo Tadino earthquake occurred on a WSW-dipping, normal fault, with a length of about 8 km and a relatively gentle dip (30°–40°), confined between 3.5 and 7 km in depth. Kinematics of the mainshock and aftershocks revealed a NE-trending extension, in agreement with the regional stress field active in the Northern Apennines belt. The Mw = 5.1 earthquake originated above the top of the basement and ruptured within the sedimentary cover, which consists of an evaporites–carbonates multilayer. We hypothesised that the active fault does not reach the surface (blind normal fault). 相似文献
12.
厦门-金门大桥桥址地处闽东南沿海断隆带和泉州-汕头地震带南段,濒临台湾海峡,具有独特的地震地质构造环境。为了保障跨海大桥的长期安全性,无疑应对桥址地区的地震地质稳定性进行必要的研究,以期为工程设计提供科学依据。 本文依据近30多年来,对该地区地质构造调查、陆海地球物理探测、地壳形变观测、地震活动性、地壳动力学和工程场地特征等资料进行了比较系统研究,结果表明该区断块构造自晚第四纪以来,呈间歇性上升运动,速率约1-2.3毫米/年,史今地震能量释放速率为(2.737-7.999)×107焦耳/公里2/年。现代地壳水平运动的速度矢量指向南东东,速度值为9-13毫米/年。从震源机制揭示,区域现代构造应力场主压应力轴(P轴)为SE125°,仰角2-8°,引张轴(T轴)为SW215°,仰角2-10°,中间轴(N轴)近垂直。这导致台湾动力触角对闽东南沿海产生强烈的推挤作用。形成潜在震源区。历史上在漳州和金门海外曾发生过61/4至61/2级地震,但桥区内未有破坏性地震(Ms≥43/4级)发生,表明厦门-金门地区构造稳定性介于泉州与南澳岛海外Ms≥7.0级地震的不稳定区之间,为相对较稳定区,适宜建跨海大桥。从地形地貌、工程地质条件显示,桥场地区由花岗岩、变质岩形成的丘陵、红土台地和第四系海陆交互相沉积层所组成。依据场地不同特点与 相似文献
13.
《Geoforum》2016
The destruction of the ancient ruins of Palmyra by the terrorist group Islamic State (IS) in September 2015 shocked the world, with some going so far as to decry it as a war crime. This paper explores why the razing of Palmyra resonated so strongly with the international community, demonstrating how the relationship between urban space and collective memory made this event so powerful. Looking to the future, it suggests that the toughest test for Palmyra is yet to come. The challenge of post-conflict reconstruction in sites such as this is inextricably bound up with questions of identity, memory and power, all of which will need to be worked out when the war in Syria eventually comes to an end. 相似文献
14.
A method for the evaluation of seismic hazard in a given zone, taking into account both the spreading of macroseismic effects and seismic catalogue information, is applied. A data-bank of some 500 digitized isoseisms of earthquakes having occurred in Italy between 1542 and 1986 is used. The isoseismical maps are digitized considering for each degree of intensity the length of 24 spreading rays starting from the macroseismic epicenter or barycentre of the megaseismic area. These rays are separated from each other by the same angle, i.e. every isoseism is divided into 24 equal circular sectors. The year 1542 is taken as the beginning of the time span, since this is when the first seismic event occurred for which reliable isoseismal maps are available. The epicentral intensities considered lie between theVI andXI degrees of the Mercalli-Cancani-Sieberg scale (MCS). This digitized data-bank is analyzed to achieve, for each homogeneous seismogenetic zone that has been recognized, the mean azimuthal spreadings of effects for each degree of intensity as a function of the epicentral intensity. Once a mean propagation model is obtained for each zone, this is applied to seismic events of the same zone, the isoseismal maps of which are not available. A geographic grid is defined to cover the analyzed area, and for each cell of this grid it is then possible to count the number of felt events and their degree. These effects have been evaluated either on the basis of the isoseismal maps (when available) or on the basis of the mean propagations of the zone in which the single event occurred. Moreover, an index summarizing the seismic information was computed for each cell of the previous grid. All the events producing effects and their provenance are stored on files, allowing the main seismogenic zones influencing this cell to be identified. This methodology has been applied to central and southern Italy in an area between the latitudes 40.6 and 43.3 N. In particular, attention is focussed on the sample areas of Rome (given the historical and political importance of the city) and of the Sannio-Matese and Irpinia zone (in which some of the strongest earthquakes of the Apennine chain have occurred). Finally, in order to evaluate the maximum expected magnitude, extreme value statistics (Gumbel III-type) are applied to the Colli Albani area, which represents the seismogenic zone nearest to Rome. For the Sannio-Matese and Irpinia area, considering the more dangerous zone as a unicum, theWeibull distribution has been hypothesized to determine the mean return time for events with an intensity greater than or equal to IX. 相似文献
15.
Matthieu Ghilardi Sylvian Fachard Kosmas Pavlopoulos David Psomiadis Christopher Collana Andrew Bicket 《Geodinamica Acta》2013,26(1-2):38-51
This article examines the shoreline evolution and human occupation in the vicinity of the important archeological site of Amarynthos (Euboea Island, Greece) over the last six millennia. Archeological evidence indicates a continuous occupation of the site from the Bronze Age to the Roman period and the site is well-known, thanks to the existence of a sanctuary dedicated to the goddess Artemis. Based on the study of four boreholes, a paleogeographic reconstruction of the coastal landscape is proposed. Facies were determined based on mollusc identification, and sedimentology based on grain-size measurements (hand sieving for the fraction above 2?mm and LASER technique for particles below 2?mm) and loss-on-ignition. In addition, a series of 12 AMS radiocarbon dates define a reliable chronostratigraphy. Results suggest the presence of a fully marine environment from the early Holocene to ca. 2600–2400?cal. BC, which developed into a brackish environment from ca. 2600–2400?cal. BC to ca. 750?cal. BC due to the deltaic progradation of the nearby stream (Sarandapotamos River). From ca. 750?cal. BC onward, coastal swamps prevailed in the study area. Human-environmental interaction is discussed and particular attention is paid to the paleolandscape configuration of Amarynthos. 相似文献
16.
Examination of damages affecting the buildings of the archaeological sites of Phaistos and Agia Triada (southern Crete) suggests that these Minoan settlements were probably destroyed by two major seismic events characterized by MKS intensities of IX–X and occurred at the end of the Protopalatial (1700 BC) and the Neopalatial (1450 BC) periods. Geological and morphological studies carried out in the neighbouring areas show the occurrence of E–W trending Quaternary normal fault segments (Spili and Agia Galini faults) that control the present topography and morphology, and exhibit steep young scarps mostly Holocene in age. These fault segments are related to a NW–SE extension direction, which is consistent with that indicated by the available focal mechanisms of the earthquakes occurring in this area in the last 50 years. Combining structural and seismic data we can infer that the Spili and Agia Galini fault segments could represent good candidates to be considered active faults generating large earthquakes (M6.5) that were responsible for the damages of Phaistos and Agia Triada. This hypothesis suggests that the Minoan palatial centres were destroyed by several large earthquakes related to ruptures along distinct fault segments rather than by a single catastrophic event that caused the abrupt destruction of the Minoan civilisation in the eastern Mediterranean. 相似文献
17.
We have identified a 50-km-long active fault scarp, called herewith the Lourdes Fault, between the city of Lourdes and Arette village in the French Pyrénées. This region was affected by large and moderate earthquakes in 1660 (Io = VIII–IX, MSK 64,), in 1750 (Io = VIII, MSK 64) and in 1967 (Md = 5.3, Io = VIII, MSK 64). Most earthquakes in this area are shallow and the few available focal mechanism solutions do not indicate a consistent pattern of active deformation. Field investigations in active tectonics indicate an East–West trending and up to 50-m-high fault scarp, in average, made of 3 contiguous linear fault sub-segments. To the north, the fault controls Quaternary basins and shows uplifted and tilted alluvial terraces. Deviated and abandoned stream channels of the southern block are likely due to the successive uplift of the northern block of the fault. Paleoseismic investigations coupled with geomorphic studies, georadar prospecting and trenching along the fault scarp illustrate the cumulative fault movements during the late Holocene. Trenches exhibit shear contacts with flexural slip faulting and thrust ruptures showing deformed alluvial units in buried channels. 14C dating of alluvial and colluvial units indicates a consistent age bracket from two different trenches and shows that the most recent fault movements occurred between 4221 BC and 2918 BC. Fault parameters and paleoseismic results imply that the Lourdes Fault and related sub-segments may produce a MW 6.5 to 7.1 earthquake. Fault parameters imply that the Lourdes Fault segment corresponds to a major seismic source in the western Pyrénées that may generate earthquakes possibly larger than the 1660 historical event. 相似文献
18.
Surface ruptures induced by the devastating 1068 AD earthquake in the southern Arava valley, Dead Sea Rift, Israel 总被引：2，自引：1，他引：2
The Elat fault (a segment of the Dead Sea Transform) runs along the southern Arava valley (part of the Dead Sea Rift, Israel) forming a complex fault zone that displays a time-dependent seismic behaviour. Paleoseismic evidence shows that this fault zone has generated at least 15 earthquakes of magnitude larger than M 6 during the late Pleistocene and the Holocene. However, at present the Elat fault is one of the quietest segments of the Dead Sea Transform, lacking even microsesimicity. The last event detected in the southern Arava valley occurred in the Avrona playa and was strong enough to have deformed the playa and to change it from a closed basin with internal drainage into an open basin draining to the south.Paleoseismological, geophysical and archaeological evidences indicate that this event was the historical devastating earthquake, which occurred in 1068 AD in the eastern Mediterranean region. According to the present study this event was strong enough to rupture the surface, reactivate at least two fault branches of the Elat fault and vertically displace the surface and an early Islamic irrigation system by at least 1 m. In addition, the playa area was uplifted between 2.5 and 3 m along the eastern part of the Elat fault shear zone. Such values are compatible with an earthquake magnitude ranging between M 6.6 and 7. Since the average recurrence interval of strong earthquakes during the Holocene along the Elat fault is about 1.2 ± 0.3 ky and the last earthquake occurred more about 1000 years ago, the possibility of a very strong earthquake in this area in the future should be seriously considered in assessing seismic hazards. 相似文献
19.
雪峰山西侧地带的地洼型造山-造盆作用 总被引：4，自引：2，他引：4
在晚三叠世前长期处于地台体制的雪峰山西侧地带,上三叠统和中-新生界的沉积相、物质成分、构造变动和地台构造层的构造变动反映,这里于地洼阶段发生了强烈的造山-造盆作用,造成了当今海拔反差达约千米的盆、山景观。这类地洼型造山-造盆作用具有多种运动方式。 相似文献
20.
山岳地区强烈地震诱发的滑坡、崩塌等地震次生灾害在造成严重人员伤亡的同时,对社会经济的发展也构成了严重威胁。而震后滑坡分布的快速评估,尤其是滑坡重灾区的确定,则可为救援工作的科学部署和有效开展提供决策支持并减轻地震灾害的损失。2017年8月8日发生于四川省阿坝州九寨沟风景区的MS 7.0级地震诱发了大量的滑坡、崩塌灾害,造成了一定的人员伤亡和财产损失,凸显出进行震后滑坡快速评估的重要性。本文通过对九寨沟地震灾区震前、震后“北京二号”遥感影像的对比分析,解译此次地震诱发的滑坡分布概况。尽管震后影像在局部区域有云团覆盖,影响了震区滑坡解译的详尽程度,但是对于主要发生的滑坡地震高烈度地区(≥Ⅻ度),本文所用影像基本满足解译要求。本文共解译出194个面积大于700 m2的滑坡,这些滑坡主要沿地震烈度长轴方向分布,灾害体平面面积达5.6 km2,影响范围超过600 km2。通过对九寨沟地震灾区的地形、岩性及地震动加速度进行分析,本文采用Newmark刚体滑块模型对该区震后滑坡危险区域进行了预测。预测结果按照危险程度不同划分为5个级别,即高度危险、较高危险、中度危险、较低危险和低度危险。滑坡分布与评估结果呈现出较好的一致性:解译的滑坡主要分布在评估为滑坡高度危险的区域,表明本文所采用方法的有效性。本文对该方法的局限性也进行了讨论,并提出改进建议。 相似文献