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1.
在讨论地震地质背景基础上,综合分析了震区的深部构造、地表活动断裂、地面形变、极震区展布方向、震害、余震分布、震源机制解等发震构造标志,并且进一步探讨了发震机制。初步认为北北西向罗明坝-太平断裂和北东向飞陵-丙麻断裂是2001年施甸地震的主要发震构造,二者具有共回轭构造活动的特征。  相似文献   

2.
岫岩—海城5.6级地震地震地质背景及其发震构造   总被引:3,自引:0,他引:3  
讨论了1999年11月29日岫岩-海城5.6级地震的地震地质背景,并依据地震震中分布、等震线形态、地震与断裂的关系等分析了此次地震的发震构造。结果表明,官次地震仍然是海城地震区内的地震活动,其发震构造是NW向海城河断裂。  相似文献   

3.
1994年9月16日台湾浅滩7.3级地震发震构造的讨论   总被引:1,自引:0,他引:1  
从台湾海峡与台湾浅滩的地貌特征、区域构造格局、海峡盆地形成历史、深部构造与断裂构造、震源机制解以及地震活动等方面论述了台湾浅滩7.3级地震的发震构造,认为北东东向澎湖-北港隆起南侧断裂(义竹断裂)是该地震的发震构造。  相似文献   

4.
根据两次地震的宏观考察结果、地震学有关参数以及最新的有关人工地震勘探资料的综合分析,讨论了两次绵竹5级地震和1994年江油4.7级地震、1993年郫县4.4级地震的发震构造,认为龙门山断裂及山前隐伏断裂均属浅表出露深部错动型(即滑脱型)地震断裂,并对有关强震的发震构造与构造关系进行了初步的研究。  相似文献   

5.
在分析了地震地质、物探、卫片等新的资料的基础上,认为在菏泽地震区地下隐伏着一条北东向深大断裂带。地震区内的解元集-小留集断裂与北西向的成武-定陶断裂构成共轭破裂导致藻泽5.9级地震发生,北东向断裂是其主要的发震构造。由菏泽5.9级地震前沿发震断层的ML≥3.0级地震震中迁移、震源深度的变化及跨断层形变测量资料表明,发震断层在区域构造应力场的作用下逐步克服障碍,使断层贯通,与此同时在发震构造断层面上  相似文献   

6.
1584年肇庆两次5.0级地震属于双震。两次地震等烈度线长轴均呈北西向。震中附近有两条较大的断裂,一是北东向高要断裂,它是吴川-四会断裂的分支断裂,并控制了一系列地震分布,可谓之控震构造。另一条是北西向白土断裂,与两次地震等烈度线长轴一致,联系到1905年43/4级地震也发生在此断裂附近,该断裂应是本次地震发震构造。  相似文献   

7.
核电厂地震安全性评价中的地震构造法,要求鉴定发震构造和划分地震构造区,在以往实践中,发震构造鉴定往往基于地表活动断裂构造,且表征为线状震源.当存在较强非随机分布的地震活动且难以找到清晰的地表活动断裂构造形迹时,地震构造法就难以合理地表现这些地震的危险性.本文以云南滇中大姚—姚安发震构造鉴定为例,探讨了在地表活动构造形迹不清,中强地震活动性较强的滇中大姚—姚安地区,采用面状发震构造来表征地震危险性的方法,讨论了在地震构造法中采用面状发震构造的必要性、鉴定思路和方法,并建议在今后的核工程地震危险性评价地震构造法中应充分考虑面状发震构造的应用.  相似文献   

8.
马文静  苏旭 《地震》2000,20(2):69-76
在分析青海共和地区深浅部地质构造、区域应力场等资料的基础上,提出了1990年共和7.0级地震孕震的构造动力学模式,即:NWW向至NE向断裂组合孕震,NWW向哇玉香卡-拉干隐伏断裂为发震断裂、NE向隐伏断裂为诱震断裂,NE向区域构造应力的增强为孕震和发震的主要力源。  相似文献   

9.
澜沧—耿马地震发震构造初步研究   总被引:2,自引:0,他引:2  
本文根据澜沧—耿马地震形变带、极震区及余震序列分布特征,分析了7.6和7.2级地震的发震构造,认为北北西向旱母坝断层是7.2级地震的发震构造,7.6级地震的发震构造不是一条单一的断层,北西向木嘎断裂和北北西向澜沧—勐海断裂均有明显破裂表现,这一特点与震区复杂的地质构造背景有密切联系。  相似文献   

10.
通过对金沙江涛源盆地东缘断裂活动性的调查和探测,在该盆地内发现许多有地震地质意义的构造现象。分析显示:涛源盆地东缘的金沙江河谷断裂是由一组晚更新世以来活动的铲式正断层组成,以粘滑为主,距今大约4.5万年以来的垂直活动速率为0.6 mm/a;盆地内的NW—NWW向断层是一组与金沙江河谷断裂共轭活动的正断层,距今2.2~4.4万年发生过一次7级左右的地震位错事件;程海—宾川断裂中段的潜在震源区震级上限宜取7.5级。  相似文献   

11.
2009年云南姚安6.0级地震震源机制与发震构造的分析研究   总被引:1,自引:0,他引:1  
利用P波、SV波、SH波初动及其振幅比联合反演震源机制解的方法,计算了2009年7月9日发生在云南姚安6.0级地震余震序列的震源机制解,同时结合地震序列的空间分布,对姚安6.0级地震的发震断层性质和震区应力场特征进行综合分析。结果分析表明:(1)姚安6.0级地震发震断层为NWW—SEE向的直立右旋走滑断层,与美国哈佛大学的主震CMT解节面基本一致,也与余震优势方向分布一致,证明结果可靠;(2)震区主压应力场优势方向为NNW—SSE向,与其现今区域构造应力场主压应力NNW—SSE向一致,表明主震应力场主要受到现今区域构造应力场的控制,同时还有一些小的余震与主震应力场不同,表明震区应力场的多样性和复杂性;(3)结合本次地震序列的空间分布、震源机制解特征、震区断裂构造特征综合分析,综合判定姚安6.0级地震的发震构造属于马尾箐断裂。  相似文献   

12.
本文根据地震和地震构造等资料,研究华北地区公元1300年以来MS≥6.5级地震的发震断裂的基本参数.利用1966年以来隆尧、海城、渤海和唐山等有仪器记录的地震的相关参数进行回归分析得出了地震烈度Ⅷ度区长轴长度与余震区长轴长度的回归关系式及震级与震源体破裂长度的回归关系式.用余震区长轴长度代替震源体的破裂长度,从而给出各次地震的震源断层破裂长度.利用地震测深的地壳结构构造剖面、地震序列的震源分布、壳内低速层和地壳上部的构造、盆地构造与居里面分布和已知地震震源分布等资料推断了震源破裂的上下界.基于一定的合理假定推导出了断层滑动角的估计方法,并应用于本研究区,得出了各次事件的断层滑动角.  相似文献   

13.
景泰5.9级地震的断层形变异常及中短期预报   总被引:10,自引:0,他引:10       下载免费PDF全文
初步研究了2000年6月6日甘肃景泰5.9级地震蕴育过程中近源区及外围地区断层形变异常的时空分布特征:震前断层形变异常分布范围广、异常形态复杂,断层形变(应变)类信息指标图象异常区明显.不同地域断层形变异常形态及幅度存在显著差异,与异常所处的构造部位密切相关:海原断裂带西段出现的,,相断层形变异常,显示了近源区断层运动由准线性走向非线性的过程,与断层形变(应变)类信息指标高值异常区相配合,反映蕴震区应变积累程度高;而构造汇聚部位的六盘山断裂带等远场区较大幅度的突跳尖点异常,并不反映所在地的应变积累,而可能是蕴震过程区域构造应力场增强的一个标志.在此基础上,结合对景泰5.9级地震中短期预报经验教训的初步总结,研究和探讨了断层形变异常在震情判定中的应用.   相似文献   

14.
IntroductionOn June 6, 2000, an earthquake of MS=5.9 occurred in Jingtai county, Gansu Province. The epicenter (37.1(N, 104.0(E) was located in Maomaoshan-Laohushan zone of the western segment of Liupanshan-Haiyuan fault along the northeastern margin of Qinghai-Xizang Plateau, where is the middle-eastern part of crustal deformation monitoring area of Gansu-Ningxia- Qinghai region. There are more than 50 spanning-fault mobile monitoring sites in the earthquake area and its vicinity (Fig…  相似文献   

15.
延怀盆地设定地震浅析   总被引:2,自引:0,他引:2       下载免费PDF全文
文彦君 《地震工程学报》2008,30(2):159-162,183
通过延怀盆地构造背景、新构造活动、古地震等资料的分析,综合构造应力场模拟、构造类比、大震离逝率、孕震蓄能等因素及由经验公式推断的研究结果,对延怀盆地设定地震相关参数进行了研究.结果表明,延怀盆地设定地震的震级上限为7,发震断层为方家冲一营门矿段断层,震源深度为10 km左右.  相似文献   

16.
从余震序列分布、震源机制、断裂构造、地震烈度和发震构造,简要论述九寨沟MS7.0地震及构造背景,在此基础上,整理此次地震198条强震动记录,分析强震动峰值加速度分布特征(衰减规律)及构造影响因素,发现峰值加速度在发震断层两侧的衰减具有明显的不对称性,其中NE向衰减缓慢,SW向衰减迅速,该现象不仅与发震断层的倾向、倾角有关,还与不同构造块体的介质差异密切相关。  相似文献   

17.
On October 17, 2014, a MS6.6 earthquake occurred in Jinggu, Yunnan. The epicenter was located in the western branch of Wuliang Mountain, the northwest extension line of Puwen Fault. There are 2 faults in the surrounding area, one is a sinistral strike-slip and the other is the dextral. Two faults have mutual intersection with conjugate joints property to form a checkerboard faulting structure. The structure of the area of the focal region is complex. The present-day tectonic movement is strong, and the aftershock distribution indicates the faulting surface trending NNW. There is no obvious surface rupture related to the known fault in the epicenter, and there is a certain distance from the surface of the Puwen fault zone. Regional seismic activity is strong. In 1941, there were two over magnitude 7.0 earthquakes in the south of the epicenter of Jinggu County and Mengzhe Town. In 1988, two mainshock-aftershock type earthquakes occurred in Canglan-Gengma Counties, the principal stress axes of the whole seismic area is in the direction of NNE. Geological method can be adopted to clarify the distribution of surficial fracture caused by active faults, and high-precision seismic positioning and spatial distribution characteristics of seismic sequences can contribute to understand deep seismogenic faults and geometric features. Thus, we can better analyze the three-dimensional spatial distribution characteristics of seismotectonics and the deep and shallow tectonic relationship. The focal mechanism reveals the property and faulting process to a certain extent, which can help us understand not only the active property of faults, but also the important basis for deep tectonic stress and seismogenic mechanism. In order to study the fault characteristic of the Jinggu earthquake, the stress field characteristics of the source area and the geometric parameters of the fault plane, this paper firstly uses the 15 days aftershock data of the Jingsuo MS6.6 earthquake, to precisely locate the main shock and aftershock sequences using double-difference location method. The results show that the aftershock sequences have clustering characteristics along the NW direction, with a depth mainly of 5~15km. Based on the precise location, calculations are made to the focal mechanisms of a total of 46 earthquakes including the main shock and aftershocks with ML ≥ 3.0 of the Jinggu earthquake. The double-couple(DC)component of the focal mechanism of the main shock shows that nodal plane Ⅰ:The strike is 239°, the dip 81°, and the rake -22°; nodal plane Ⅱ, the strike is 333°, the dip 68°, and the rake -170.31°. According to focal mechanism solutions, there are 42 earthquakes with a focal mechanism of strike-slip type, accounting for 91.3%. According to the distribution of the aftershock sequence, it can be inferred that the nodal plane Ⅱ is the seismogenic fault. The obtained focal mechanism is used to invert the stress field in the source region. The distribution of horizontal maximum principal stress orienation is concentrated. The main features of the regional tectonic stress field are under the NNE-SSW compression(P axis)and the NW-SE extension(T axis)and are also affected by NNW direction stress fields in the central region of Yunnan, which indicates that Jinggu earthquake fault, like Gengma earthquake, is a new NW-trending fault which is under domination of large-scale tectonic stress and effected by local tectonic stress environment. In order to define more accurately the occurrence of the fault plane of the Jinggu earthquake, with the precise location results and the stress field in the source region, the global optimal solution of the fault plane parameters and its error are obtained by using both global searching simulated annealing algorithm and local searching Gauss-Newton method. Since the parameters of the fault plane fitting process use the stress parameters obtained by the focal mechanism inversion, the data obtained by the fault plane fitting is more representative of the rupture plane, that is, the strike 332.75°, the dip 89.53°, and the rake -167.12°. The buried depth of the rupture plane is 2.746km, indicating that the source fault has not cut through the surface. Based on the stress field characteristics and the inversion results of the fault plane, it is preliminarily believed that the seismogenic structure of the Jinggu earthquake is a newly generated nearly vertical right-lateral strike-slip fault with normal component. The rupture plane length is about 17.2km, which does not extend to the Puwen fault zone. Jinggu earthquake occurred in Simao-Puer seismic region in the south of Sichuan-Yunnan plate. Its focal mechanism solution is similar to that of the three sub-events of the Gengma earthquake in November 1988. The seismogenic structure of both of them is NW-trending and the principal stress is NE-SW. The rupture plane of the Jinggu main shock(NW direction)is significantly different from the known near NS direction Lancang Fault and the near NE direction Jinggu Fault in the study area. It is preliminarily inferred that the seismogenic structure of this earthquake has a neogenetic feature.  相似文献   

18.
四川较场弧形构造与1933年叠溪地震发震构造的再讨论   总被引:5,自引:0,他引:5  
较场弧形构造是四川众多弧形构造带之一。本文对该弧形构造的特征及其西冀发育的松平沟断裂的新活动性作了进一步论证,确认松平沟断裂属全新世活动断裂。该弧形构造西翼弧顶部位1933年曾发生过叠溪7.5级地城,丧人对该次地震的发震构造众说纷纭。作者通过近年来在现场的多次考察,并对该次地震的等烈度线形态,地表震害展布特征,建筑物沿松平沟断裂的左旋位错,震后持表发育的西北向地震地裂缝等现象的进一步研究认为,1933年叠溪7.5级地震的发展震构造仍为较场弧形构造西翼的松平沟断裂。  相似文献   

19.
基于高分辨率卫星影像解译,通过野外地质地貌填图与差分GPS测量,初步获得了帕米尔高原1895年塔什库尔干地震地表破裂带的空间展布、破裂类型、位移及分布等基本参数,据此估算了可能的地震震级,讨论了其宏观震中及发震构造模型.塔什库尔干地震使得慕士塔格正断层南段的部分和整个塔合曼正断层发生破裂,形成了长约27km的地震地表破...  相似文献   

20.
在对2013年4月20日芦山MS7.0地震灾区大量地震地质灾害实地考察及调查的基础上, 总结了滑坡、 崩塌、 砂土液化、 地裂缝、 地表变形等地震地质灾害的分布及发育特点, 探讨了地震地质灾害与发震断裂之间的关系. 极震区和重灾区的崩塌和滑坡特别严重, 是地震巨大破坏作用的外在表现形式; 砂土液化点较少, 分布范围和规模有限; 地裂缝和地表变形并非真正意义上的地震地表破裂带. 根据极震区和重灾区地震地质灾害的分布和发育特点, 认为芦山地震最有可能的发震断裂为龙门山前山断裂的双石—大川断裂, 也有可能是龙门山山前隐伏断裂的大邑断裂, 还有可能是双石—大川断裂与大邑断裂两者共同触发的结果.   相似文献   

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