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1.
2016年11月25日,在新疆阿克陶县发生了MW6.6地震.本文利用Sentinel-1A宽幅数据和ALOS2精细数据获得了同震形变场,干涉形变场沿木吉断裂展布,显示本次地震破裂长度可达70 km,在地表形成两个形变中心,且震中东部形变场条纹密集而西部稀疏、影响范围广,跨断层剖面显示视线向最大形变量可达12 cm.利用一种结合先验知识的多视角最小二乘迭代分解法求解出地表的三维形变场,结果显示震中东部形变中心垂向向下运动最大可达20 cm,木吉断裂南侧西向运动可达10 cm,断层表现为右旋走滑兼具正断作用.采用前向模拟的方法确定二段式分段断层模型能够较好地恢复观测形变场,进而以InSAR观测数据为约束,基于弹性半空间形变模型采用两段非均匀断层滑动模型来反演断层面上的精细滑动值.反演结果显示本次地震可能为两次地震事件,发生在断层西段的第一次事件以右旋走滑为主,走向103°,倾角76°,滑动角-167°,震源深度10.1 km,累计地震矩为7.2×1018N·M;东段的第二次事件为右旋走滑兼具正断作用,走向109°,倾角略缓约55°,滑动角-160°,震源深度5.3 km,累计地震矩7.76×1018N·M.本次地震是一次发生在公格尔拉张系的拉张环境下的构造地震. 相似文献
2.
2016年11月25日新疆阿克陶地区发生的MW6.6地震,对当地人民生命造成一定的危害。基于Sentinel-1数据获取该地震的视线向同震形变场,采用贝叶斯方法反演单一断层走向为106.9°、倾角为73.8°、震源深度为17.35 km,在此断层几何模型基础上,以最速下降梯度法（Steepest Descent Method,SDM）反演滑动分布,结果表明断层面上存在两个滑动峰值,其中位于断层西侧的最大滑动量为0.66 m,深度为11.7 km,位于断层东侧的最大滑动量为0.83 m,深度为7.5 km,根据反演结果模拟LOS形变,其最大残差为~5 cm。构建倾角分别为70.79°和55.33°的双断层几何模型,并根据双断层几何模型反演了滑动分布,结果表明单一断层模型与双断层模型的滑动分布具有一致性,但是最大滑动量值有所不同,相对于单一断层模型的滑动分布而言,双断层模型的滑动量在西侧增大,其值为0.68 m;而在东侧减小,其值为0.77 m;最大残差降低了约2 cm。双断层模型库伦应力增加区域与余震的分布比较吻合。 相似文献
3.
2015年4月25日,在尼泊尔中部发生了Mw7.8地震.本文利用ALOS-2和SENTINEL-1A宽幅数据获取了该地震大范围的同震形变场,并反演了该地震断层破裂的几何特征及运动机制,继而以此为约束资料反演地震强地面运动.InSAR结果显示本次地震造成了巨大的地表形变,LOS向最大抬升量达到1.3 m,最大下沉量达到0.7 m.震源机制反演得到的最优的滑动分布模型表明,断层的走向为291°,倾角为7.6°,倾滑主要分布在深度为12~18 km范围,主倾滑分布范围在长度上达到了140 km,该范围内的平均倾滑角为95°.本次地震最大倾滑量达到5.3 m,位于深度15 km处.累计释放地震矩达 6.5×1020N·m,约合矩震级Mw7.8.该地震发生在印度与欧亚板块俯冲逆冲界面之间,发震构造推断为主喜马拉雅逆冲断裂,属于典型的喜马拉雅型——低角度逆断层型强震.以该滑动分布模型参数为基础利用随机振动的有限断层模型进行尼泊尔地震的强地面运动模拟,结果显示最大地震烈度为Ⅸ度,烈度分布的范围及烈度等级与USGS模型结果对比具有很高的符合度. 相似文献
4.
运用Sentinel-1A卫星数据和D-InSAR技术,获取2021-05-21云南漾濞M_S6.4地震的同震形变场。结果显示,漾濞地震同震形变场长轴近NW展布升降轨形变场符号相反,视线向最大沉降量和抬升量为0.1 m。InSAR同震形变场反演的滑动分布主要集中在沿走向2～12 km,倾向1～9 km的范围内,最大滑动量0.35 m,发震断层长9.8 km、宽4 km,滑动量主要集中在地下3～6 km范围内,滑动角-146.7°。同震位移场及滑动分布模型反映本次地震为发震断层的右旋走滑事件,地震破裂未达到地表。断层模型反演结果显示,矩震级为M_W6.1,发震断层以北西走向右旋走滑运动为主,初步认为本次M_W6.1地震发震断裂可能是一条NW向的维西—乔后断裂西侧的隐伏次生断裂。 相似文献
5.
2017年8月8日的九寨沟MS7.0地震发生在岷江断裂、塔藏断裂及虎牙断裂交汇地区,地处青藏高原东北部的川甘交界地区,位于巴颜喀拉地块的东缘,地质构造复杂,对于九寨沟地震震中位置和发震断层的确定,存在不同意见.本文利用GNSS及升降轨InSAR观测,在获取九寨沟地震同震形变场的基础上,基于均匀弹性半无限位错模型,联合反演了发震断层的滑动分布模型,并计算了同震库仑应力变化.InSAR同震形变场显示,视线向最大沉降量和抬升量分别为0.21 m和0.16 m,形变场长轴为NW向,形变主要集中在断层西侧.距震中40 km和65 km的九寨和松潘两县,水平向的GNSS同震位移分别达14.31 mm和8.22 mm.联合GNSS和InSAR同震形变场反演得到的滑动分布主要集中在沿走向5~33 km,倾向2~20 km的范围内,平均滑动量为0.18 m,最大滑动量为0.91 m.发震断层长40 km,宽30 km,走向155°,倾角81°,滑动角-9.56°.同震位移场及滑移分布模型表明此次地震为一次左旋走滑为主的地震事件,地震破裂并未完全到达地表,与虎牙断裂北段的几何产状和运动学性质更为接近,结合精定位余震的分布,我们确定虎牙断裂北段为此次地震的发震断层,震中位于北纬33.25°,东经103.82°,震源深度10.86 km,矩震量为7.754×1018 Nm,相应的矩震级为MW6.5,与美国地调局和哈佛大学给出的震源机制解基本一致.同震库仑应力导致了虎牙断裂北段延长线的东北和西南两端应力增强,其中塔藏断裂的罗叉段和马磨段未来强震的危险性值得关注. 相似文献
6.
2008年10月5日新疆乌恰Mw6.7级地震发生在南天山、帕米尔高原及塔里木盆地交汇地带,基于地震波反演的震源机制解确定的震源深度存在较大差异.本文利用日本ALOS卫星的PALSAR图像,获得了本次地震的同震形变场,基于卫星视线向（LOS）和方位向（Azimuth）的形变,采用均匀弹性半无限位错模型和有界最小二乘（BVLS）算法,以网格矩形位错元法对发震断层的几何产状、滑移及分布进行了估算,结果表明本次地震以逆断破裂为主,断层面上最大位错量接近3.4 m,形变中心位于73.8040°E,39.5335°N,深度约5 km,震级估算为Mw6.6;地震发生在走向46°,倾角48°的断层上,发震断层长30 km,宽14 km,闭锁深度9 km,符合该地区浅源地震多发的构造特点,发震断层为乌合沙鲁断裂带.InSAR反演的滑移形变主要集中于地下2~7 km,表明乌恰地震为浅源地震,可能与该断层附近历史地震未完全释放的残余应力积累有关.同时,InSAR反演的断层位错分布呈现双破裂特征,震级分别为Mw6.5和Mw6.1,可能与本次地震的主震和余震相对应,也可能是由主震激发而产生的两组破裂. 相似文献
7.
2021年5月21日晚21时48分,云南省大理州漾濞县(震中:25.67°N,99.87°E)发生M_S6.4地震,震源深度8 km。为快速获得此次地震同震形变场及断层几何参数,研究该次地震的发震构造等,文章基于震前、震后的sentinel-1A卫星升降轨SAR数据进行二轨法差分雷达干涉测量(DInSAR),并基于Okada弹性半空间位错模型反演断层几何参数。研究结果如下:(1)此次地震造成的同震形变场长约19 km,宽约20 km;(2)升轨雷达视线向最大形变约为8.2 cm,降轨雷达视线向最大形变约为8.7 cm;(3)地震断层走向为313.7°,倾角为87°,滑动角为175°,为右旋走滑型断层,最大滑动量为0.79 m,反演得出的地震矩为1.48×10~(18) N·m,矩震级为M_W6.1。在川滇块体向南挤出的构造背景下,块体西边界的维西—乔后断裂、红河断裂发生右旋走滑,本次地震便是维西—乔后断裂南段分支断裂右旋走滑活动的体现。 相似文献
8.
In this study,data from the Xinjiang regional network and IRIS shared global stations are used to relocate the Akto M_S6. 7 earthquake sequence on November 25,2016 by using double difference location method. Three earthquakes of M_S4. 8,M_S6. 7 and M_S5. 0 are inverted by using the g CAP method,and the focal mechanism solutions are obtained.According to the results of relocating,the location of the main shock is 39. 22°N,73. 98°E,the distribution of the earthquake sequence is about 70 km in length,and the focal depth is mainly within the range of 5-20 km. The plane and depth profiles of the earthquake sequence show that aftershocks extended in SEE direction after the main shock and the dip angle of fault plane is steep. Focal mechanism results show that the three earthquakes are characterized by strike-slip movement. Based on the results of field geological investigation,it is inferred that the seismogenic fault of the Akto earthquake is Muji fault,which is located at the northernmost end of the Kongur extensional system.The possible cause of this earthquake is that the Indian Plate continues to push northward,and during this compression process,the Indian Plate is affected by the clockwise rotation of the Tarim basin,which causes the accumulation of right-lateral action of the Muji fault,resulting in this earthquake. 相似文献
9.
采用DInSAR技术和欧空局2014年新发射的Sentinel-1A/IW数据,获取了2015年4月25日尼泊尔M_W7.8地震的InSAR同震形变场.所用InSAR数据扫描范围东西长约500 km,南北宽约250 km,覆盖了整个变形区域,揭示了形变场的全貌及其空间连续变化形态.此次地震造成的地表形变场总体呈现为中部宽两端窄的纺锤形,从震中向东偏南约20°方向延伸,主要形变区东西长约160 km,南北宽约110 km,由规模较大的南部隆升区和规模较小的北部沉降区组成,南部最大LOS向隆升量达1.1 m,北部最大LOS向沉降量约在0.55 m.在隆升和沉降区之间干涉纹图连续变化,没有出现由于形变梯度过大或地表破裂而导致的失相干现象,表明地震断层未破裂到地表.基于InSAR形变场和部分GPS观测数据,利用弹性半空间低倾角单一断层面模型进行了滑动分布单独反演和联合反演,三种反演结果均显示出一个明显的位于主震震中以东的滑动分布集中区,向外围衰减很快,主要滑动发生于地下7~23 km的深度范围内.InSAR单独反演的破裂范围,特别是东西向破裂长度大于GPS单独反演的破裂长度,而InSAR单独反演的最大滑动量则低于GPS单独反演的滑动量.因此认为联合反演结果更为可靠.联合反演的破裂面长约150 km,沿断层倾向宽约70 km,最大滑移量达到4.39 m,矩震级为M_W7.84,与之前用地震波数据和GPS数据反演的结果一致. 相似文献
10.
Samir Belabbès Mustapha Meghraoui Ziyadin Çakir Youcef Bouhadad 《Journal of Seismology》2009,13(4):421-432
We study the surface deformation associated with the 22 December 1999 earthquake, a moderate sized but damaging event at Ain
Temouchent (northwestern Algeria) using Interferometric Satellite Aperture Radar images (InSAR). The mainshock focal mechanism
solution indicates reverse faulting with a NE–SW trending rupture comparable to other major seismic events of this section
of the Africa–Eurasia plate boundary. Previously, the earthquake fault parameters were, however, poorly known because no aftershocks
were precisely determined and no coseismic surface ruptures were observed in the field. Using a pair of ERS data with small
baseline and short temporal separation in the ascending orbit we obtained an interferogram that shows the coseismic surface
displacement field despite poor coherence. The interferogram measures four fringes and displays an ellipse-shaped lobe with
∼11 cm peak line-of-sight displacement. The elastic modeling using a boundary element method (Poly3Dinv) indicate coseismic
slip reaching up to 1 m at 5 km depth on the N 57° E trending, dipping 32° NW Tafna thrust fault. The geodetic estimate of
seismic moment is 4.7 × 1017 N m. (Mw 5.7) in is good agreement with seismological results. The elliptical shape of the surface displacement field coincides
with the NE–SW trending Berdani fault-related fold. The consistency between the geological observations and InSAR solution
shed light on the precise earthquake location and related Tafna fault parameters. 相似文献
11.
2016年2月6日台湾西南部高雄市美浓区发生了MW6.4地震.本文结合ALOS2卫星升降轨、Sentinel-1A升轨SAR数据,采用两轨差分干涉技术获取了该区域的同震形变场,形变结果表明震中西北部以抬升为主,最大视线向形变量约为11.2 cm.基于均匀位错模型和多峰值粒子群（MPSO）算法,利用InSAR和GPS形变数据联合反演了美浓地震的断层几何参数,结果表明震源中心位于22.920°N,120.420°E,深度约12 km,发震断层长度约15 km,走向角307°,倾角16.5°,平均滑动角为51.5°,此次地震是以逆冲倾滑兼左旋走滑的破裂模式.利用格网迭代搜索法得到最优倾角为15.7°,GPS和InSAR最优权比为18：1,最优平滑因子为0.06.基于非均匀位错模型,利用非负最小二乘方法进行线性反演,结果显示最大倾滑和走滑量分别为51.7 cm和55.3 cm,对应矩震级为MW6.38,略小于GCMT （MW6.4）的结果.通过与已有文献的比较和对该区域断层构造的分析,发现美浓地震的发震断层为单一断层的解释更为合理,我们推测发震断层是位于左镇、后甲里等断层之间的一条东南-西北走向往东北倾斜的盲断层,并初步推测2010年MW6.3甲仙地震也同该断层有关. 相似文献
12.
黑龙江省萝北地区是东北现代地震活动最为活跃的地区之一,中小地震密集成带分布,曾于1963年发生5.8级地震,但其发震构造一直不清楚。精定位后的震中分布图像和震源机制解研究结果表明,现代地震总体呈NEE方向密集分布于黑龙江小兴安岭山前太平沟一带,地震类型以右旋走滑为主。通过高分辨率的卫星影像解译结果发现太平沟一带发育一条长约25km,走向约N70°E的线性异常带。野外地表调查发现该线性异常表现为断续分布的断裂陡坎、冲沟位错和滑坡。陡坎走向约N65°E-N75°E,倾向SE,高约1.0-2.5m;滑坡发育有典型的弧形圈椅构造,规模大小不等,多与断裂陡坎伴生。综合现代地震活动图像、卫星影像解译、野外地质调查结果,特别是结合2013年11月和2014年2月该地区的2次小震活动及现代地震活动的空间图像分布特征,研究认为太平沟断裂属于依兰-伊通断裂带的分支断裂,晚第四纪期间曾经强烈活动,具备中强地震的发震能力,可能是萝北1963年5.8级地震的发震构造。 相似文献
13.
Mahdi Motagh Jürgen Klotz Farokh Tavakoli Yahya Djamour Siavash Arabi Hans-Ulrich Wetzel Jochen Zschau 《Pure and Applied Geophysics》2006,163(1):1-18
We used new precise leveling data acquired 40 days after the Bam earthquake in combination with radar interferometry observations
from both ascending and descending orbits to investigate static deformation associated with the 2003 Bam earthquake. We invert
this geodetic data set to gain insight into the fault geometry and slip distribution of the rupture. The best-fitting dislocation
model is a steeply east-dipping right-lateral strike-slip fault that has a size of 11 by 8 km and strikes N2°W. We find that
such smooth geometry fits available geodetic data better than previously proposed models for this earthquake. Our distributed
slip model indicates a maximum strike slip of 3 m occurring about 3 to 5 km deep. The slip magnitude and depth of faulting
taper to the north, where the fault approaches the Bam city. Inclusion of crustal layering increases the amount of maximum
slip inferred at depth by about 4%. 相似文献
14.
利用于田震中300 km范围内的1个GPS连续站和12个GPS流动站数据,解算得到了2014年新疆于田MS7.3地震地表同震位移,并反演了发震断层滑动分布,探讨此次地震对周边断裂的影响.地表同震位移结果显示,GPS观测到的同震位移范围在平行发震断裂带的北东-南西向约210 km,垂直发震断裂带的北西-南东方向约为120 km,同震位移量大于10 mm的测站位于震中距约120 km以内;同震位移特征整体表现为北东-南西方向的左旋走滑和北西-南东方向的拉张特征,其中在北东-南西方向,I069测站位移最大,约为32.1 mm,在北西-南东方向,XJYT测站位移最大,约为28.1 mm;位错反演结果表明,最大滑动位于北纬36.05°,东经82.60°,位于深部约16.6 km,最大错动量为2.75 m,反演震级为MW7.0,同震错动呈椭圆形分布,以左旋走滑为主并具有正倾滑分量,两者最大比值约为2.5：1,同震错动延伸至地表,并向北东方向延伸,总破裂长度约50 km,地表最大错动约1.0 m;同震水平位移场模拟结果显示贡嘎错断裂、康西瓦断裂和普鲁断裂等不同位置主应变特征具有差异性,这种差异特征是否影响断裂带以及周围区域的应力构造特征,值得关注. 相似文献
15.
Rupture process of the 2015 Pishan earthquake from joint inversion of InSAR,teleseismic data and GPS
An earthquake of Mw6.4 occurred in Pishan County in Xinjiang Province, northwestern Tibetan Plateau, on July 3,2015. The epicenter was located on an active blind thrust system located at the northern margin of the Western Kunlun Mountain Orogenic Belt southwest of the Tarim Basin. We constructed a shovel-shaped fault model based on the layered-crust model with reference to the seismic reflection profile, and obtained the rupture process of the earthquake from the joint inversion of Interferometric Synthetic Aperture Radar(InSAR) measurements, far-field waveform data, and Global Positioning System(GPS) data. The results show that the seismic fault dips southward with a strike of 109°, and the rupture direction was essentially northward. The fault plane rupture distribution is concentrated, with a maximum recorded slip of 73 cm. The main features of the fault are as follows: low inclination angle(25°–10°), thrust slip at a depth of 9–13 km, rupture propagation time of about 12 s, no significant slip in soft or hard sedimentary layers at 0–4 km depth and propagation from the initial rupture point to the surrounding area with no obvious directionality. The InSAR time-series analysis method is used to determine the deformation rate in the source region within 2 years after the earthquake, and the maximum value is ~17 mm yr-1 in the radar line-of-sight direction. Obvious post-earthquake deformation is evident in the hanging wall, with a similar trend to the coseismic displacement field. These results suggest that the Pishan earthquake has not completely released the accumulated energy of the region, given that the multilayer fold structure above the blind fault is still in a process of slow uplift since the earthquake. Post-earthquake adjustment models and aftershock risk analysis require further study using more independent data. 相似文献
16.
1997年11月8日西藏玛尼Mw75级地震是干涉雷达技术应用于地震观测以来的一次重要事件.Peltzer等认为该形变场体现了地壳的非线性弹性形变响应，挤压象限和拉张象限的杨氏模量比值为2.相同的情形并没有在其他地震同震形变场中发现，通常用线弹性理论就能够很好地解释观测数据.考虑到他们所用断层模型的简化程度和纯走滑约束等，本研究认为非线性弹性解释是牵强的.应用广泛使用的Okada线弹性位错模型，采用卫星观测得到的地表断层位置，去除倾滑为零的约束，基于非线性优化反演方法寻求拟合雷达观测的最佳断层几何参数和均匀滑动参数.结果表明，线弹性模型能够满意解释观测数据.断层在朝阳湖以东的段落最深达到165 km，随着断层向两侧延伸，深度逐渐减小；反演得到的断层倾 相似文献
17.
Based on the analysis of coseismic deformation in the macroscopic epicentral region extracted by Differential Interferometric
Synthetic Aperture Radar (D-InSAR), and combined with the seismic activity, focal mechanism solutions of the earthquake and
field investigation, the characteristic of coseismic deformation of M
S=8.1 western Kunlunshan Pass earthquake in 2001 was researched. The study shows that its epicenter lies in the northeast side
of Hoh Sai Hu; and the seismogenic fault in the macroscopic epicentral region can be divided into two central deformation
fields: the west and east segments with the lengths of 42 km and 48 km, respectively. The whole fault extends about 90 km.
From the distribution of interferometry fringes, the characteristic of sinistral strike slip of seismogenic fault can be identified
clearly. The deformations on both sides of the fault are different with an obviously higher value on the south side. In the
vicinity of macroscopic epicenter, the maximum displacement in look direction is about 288.4 cm and the minimum is 224.0 cm;
the maximum sinistral horizontal dislocation of seismogenic fault near the macroscopic epicenter is 738.1 cm and the minimum
is 551.8 cm.
Foundation item: National Natural Science Foundation of China (40374013) and “Researching on the Disaster Earthquake” (2003) of Public Welfare
Research Item, Ministry of Science and Technology of China. 相似文献
18.
通过综合分析2008年5月12日汶川地震野外地震地质考察的地表破裂带空间分布及分段资料,结合InSAR干涉形变场资料,构建了五段断层儿何结构模型,该模型与野外地震地质考察结果在多数分段上基本一致;基于此五段断层模型,运用敏感性迭代拟合算法反演了汶川地震InSAR同震形变场,获得了断层滑动分布及部分震源参数.结果表明,基于余震精定他获得的地震断层倾角模型模拟的同震形变场与InSAR形变场吻合较好,且残差较小;反演的滑动分布主要集中于地下0～20 km,最大滑动量分别位于北川及青川等地区,最大可达到10 m;沿SW-NE走向,断层面的滑动方向主要以右旋兼逆冲形式为主,在汶川及都江堰地区以强烈的逆冲为主兼有一定右旋走滑分量,在北川及映秀地区以逆冲兼右旋运动为主,在平武及青川等地区则逐渐过渡为以右旋运动为主兼有一定的逆冲分量,其中汶川地区的平均滑动角为97°,北川地区的平均滑动角为119°,青川地区平均滑动角为138°.反演矩张量为7.7×10~(20)N·m,矩震级达M_w7.9. 相似文献
19.
利用Sentinel-1A升轨和降轨数据,基于D-InSAR技术,获取2020年1月19日伽师MS6.4地震同震形变场,并结合其他研究机构给出的震源机制解参数和已有研究成果,反演得到伽师地震的发震断层几何特征和滑动分布。研究结果表明,伽师地震同震形变在地表有明显差异;升轨同震形变在卫星视线方向北侧抬升55 mm,南侧下降42 mm;降轨同震形变在卫星视线方面北侧抬升63 mm,南侧下降23 mm。通过反演得到发震断层走向为275°,倾角为20°,地震滑动主要分布在地下5 km处,最大滑动量约为0.32 m,平均滑动角为89.3°,累积地震矩为1.46×1018 N·m,合矩震级MW6.1,发震构造为具有少量走滑性质的逆冲断裂。从发震构造特征、同震滑动分布推测,伽师地震发震构造是柯坪塔格褶皱带滑脱面以上沉积盖层内的逆冲断裂,支持了柯坪推覆体的薄皮构造模型观点。 相似文献
20.
《地震研究进展（英文）》2021,1(2):100027
A remarkable earthquake struck Yutian, China on June 26th, 2020. Here, we use Sentinel-1 images to investigate the deformation induced by this event. We invert the InSAR observations using a two-step approach: a nonlinear inversion to constrain fault geometries with uniform slip based on the rectangular plane dislocation in an elastic half-space, followed by a linear inversion to retrieve the slip distribution on the fault plane. The results show that the maximum LOS displacement is 22.6 cm, and the fault accessed to the ruptured characteristics of normal faults with the minor left-lateral strike-slip component. The fault model indicates a 210° strike. The main rupture zone concentrates in the depth of 5–15 km, and the fault slip peaks at 0.89 m at the depth of 9 km. Then, we calculate the variation of the static Coulomb stress based on the optimal fault model, the results suggest that the Coulomb stress of the Altyn Tagh fault and other neighboring faults has increased and more attention should be paid to possible seismic risks. 相似文献