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1.
The source parameters, such as moment tensor, focal mechanism, source time function (STF) and temporal-spatial rupture process,
were obtained for the January 26, 2001, India, M
S=7.8 earthquake by inverting waveform data of 27 GDSN stations with epicentral distances less than 90°. Firstly, combining
the moment tensor inversion, the spatial distribution of intensity, disaster and aftershocks and the orientation of the fault
where the earthquake lies, the strike, dip and rake of the seismogenic fault were determined to be 92°, 58° and 62°, respectively.
That is, this earthquake was a mainly thrust faulting with the strike of near west-east and the dipping direction to south.
The seismic moment released was 3.5×1020 Nm, accordingly, the moment magnitude M
W was calculated to be 7.6. And then, 27 P-STFs, 22 S-STFs and the averaged STFs of them were determined respectively using
the technique of spectra division in frequency domain and the synthetic seismogram as Green’s functions. The analysis of the
STFs suggested that the earthquake was a continuous event with the duration time of 19 s, starting rapidly and ending slowly.
Finally, the temporal-spatial distribution of the slip on the fault plane was imaged from the obtained P-STFs and S-STFs using
an time domain inversion technique. The maximum slip amplitude on the fault plane was about 7 m. The maximum stress drop was
30 MPa, and the average one over the whole rupture area was 7 MPa. The rupture area was about 85 km long in the strike direction
and about 60 km wide in the down-dip direction, which, equally, was 51 km deep in the depth direction. The rupture propagated
50 km eastwards and 35 km westwards. The main portion of the rupture area, which has the slip amplitude greater than 0.5 m,
was of the shape of an ellipse, its major axis oriented in the slip direction of the fault, which indicated that the rupture
propagation direction was in accordance with the fault slip direction. This phenomenon is popular for strike-slip faulting,
but rather rare for thrust faulting. The eastern portion of the rupture area above the initiation point was larger than the
western portion below the initiation point, which was indicative of the asymmetrical rupture. In other words, the rupturing
was kind of unilateral from west to east and from down to up. From the snapshots of the slip-rate variation with time and
space, the slip rate reached the largest at the 4th second, that was 0.2 m/s, and the rupture in this period occurred only
around the initiation point. At the 6th second, the rupture around the initiation point nearly stopped, and started moving
outwards. The velocity of the westward rupture was smaller than that of the eastward rupture. Such rupture behavior like a
circle mostly stopped near the 15th second. After the 16th second, only some patches of rupture distributed in the outer region.
From the snapshots of the slip variation with time and space, the rupture started at the initiation point and propagated outwards.
The main rupture on the area with the slip amplitude greater than 5 m extended unilaterally from west to east and from down
to up between the 6th and the 10th seconds, and the western segment extended a bit westwards and downwards between the 11th
and the 13th seconds. The whole process lasted about 19 s. The rupture velocity over the whole rupture process was estimated
to be 3.3 km/s.
Foundation item: 973 Project (G1998040705) from Ministry of Science and Technology, P. R. China, and the National Science Foundation of China
under grant No.49904004.
Contribution No. 02FE2026, Institute of Geophysics, China Seismological Bureau. 相似文献
2.
根据中国和全球地震台网记录的波形记录,采用W震相矩张量反演、反投影分析及有限断层模型反演方法,研究了2016年3月2日印尼7.8级地震破裂过程,分析讨论印尼地震震源运动学特征.结果表明：此地震为一次对称的双侧破裂走滑型事件,北北东─南南西向的断层节面（走向5°/倾角85°）为发震断层面.标量地震矩约6.19×1020 Nm,矩震级为7.79,最大的滑动量约11 m,位于破裂起始点北东,沿着断层走向约30 km处.破裂平均速度2.0~2.2 km·s-1,破裂持续时间35 s,破裂在5~25 s内释放的能量,约占总能量的97%.最终形成了总长度90 km左右的断层.印尼地震具有破裂持续时间短、破裂速度慢、高滑动能量带相对集中等显著特点.本研究对进一步增进海洋岩石圈地震的震源特性认识有重要参考意义. 相似文献
3.
Tempo-spatial rupture process of the 1997 Mani, Xizang (Tibet), China earthquake of MS=7.9 总被引：3，自引：0，他引：3
IntroductionAnearthquakeofMs=7.9occurredinMaul,Xizang(Tibet),Chinaat10:02f55.4(UTC),No')ember8.1997.TheepicenterdeterminedbyChinaNationalSeismographNetwork(CNSN)is87.33"E.3>.26'N,thefocaldepthis40km,andthemagnitudeisMs=7.4.Accordingtothedeterllllnati... 相似文献
4.
利用远震资料、近场强震资料和合成孔径雷达干涉同震形变资料确定了2017年8月9日精河MS6.6地震的断层面参数及震源破裂细节。为得到可靠的断层几何参数,发展了一套基于InSAR数据滑动分布反演的三维格点搜索流程,对本次地震断层面的走向、倾角和震源深度进行了格点搜索。结果显示,地震断层面走向为95°,倾角为47°,震源深度为14 km。基于搜索得到的断层模型进行破裂过程联合反演的结果显示:精河MS6.6地震为一次单侧破裂事件,最大滑动量约为0.8 m,滑动区域集中在断层面上震源以西5—15 km,沿倾向15—25 km,破裂主要发生在10 km深度以下区域。断层面上的平均滑动角为106°。整个破裂过程释放的标量地震矩为3.6×1018 N·m,对应矩震级为MW6.3。破裂过程持续约9 s,期间的破裂速度约为2.1—2.6 km/s。由于地震破裂主要集中在10 km以下,未来可能需要关注该区域0—10 km发生潜在地震的可能性。 相似文献
5.
为了深入认识2016年4月15日日本熊本地震破裂的复杂性,利用远场体波资料和同震InSAR资料联合反演了此次地震的震源破裂时空过程. 联合反演结果表明:熊本地震的震源破裂持续时间约为25 s,整个破裂过程释放的总标量矩为6.03×1019 N·m,对应于矩震级MW7.1;同震滑动主要集中分布于浅部,破裂以右旋走滑为主,但在沿倾向0—5 km范围内,破裂呈较强的正断特征;此次地震破裂的最大同震滑动量约为4.9 m,且最大同震位错区位于背离断层走向上、距离起始破裂点约5—10 km的区域;破裂前期（0—7 s）,在倾向上向浅表发生破裂,在走向上向东北和西南两侧扩展;大约7 s后,破裂背离断层走向主要向东北方向扩展. 根据有限断层联合反演结果推测,此次熊本地震破裂可能出露至地表. 相似文献
6.
1999年山西大同Ms 5.6地震的震源断层 总被引：9，自引：0，他引：9
大同震区先后在 1989、1991和 1999年发生MS >5地震 ,利用大同遥测地震台网的记录资料进行比较精确的地震序列震源定位 ,结合宏观烈度分布和震源机制解资料 ,详细地分析对比了 3次子序列的异同。结果显示 ,1999年MS5 .6地震的震源断层是走向NWW、长 16km、宽12km、埋深 5km以下、倾角近直立的左旋走滑断层。而前 2个子序列是NNE为主的右旋走滑断层活动所致 ,表明地震破裂方向发生了变化。这种 2个以上方向先后出现、并且强弱有别的地震破裂是普遍存在的 ,表明震源环境的复杂程度与地震序列的类型有关。虽然震区存在NE向的大王村断裂和NW向的团堡断裂 ,但目前没有证据说明震源断层和 2条构造断层连通。 3次子序列的震源断层都是走滑断层 ,也和 2条构造正断层有别。 1999年的子序列可能属于新破裂。 相似文献
7.
IntroductionOn September 27, 2003, an earthquake of MS=7.9 struck the border area of China, Russia and Mongolia. According to the field investigation from the Earthquake Administration of XinjiangAutonomous Region, the whole northern Tianshan region felt the hit. Buildings and structures within six counties and one city in Altay region, which is total about 0.11×106 km2 area, were damaged to different extent and caused certain economic losses. The epicenter determined by China National … 相似文献
8.
联合近场GPS测站1-Hz运动学位移、 强震仪加速度波形和全球台站P震相波形作为约束, 以时空滑动分布约束条件和ABIC模型参数选择方法, 结合先验的滑动方向变化范围, 反演2008年汶川MS8.0地震的震源时空破裂过程, 给出了能够综合反映震源破裂过程的统一模型。 结果表明, 汶川地震总体上存在4个主要的破裂区, 最主要的一个破裂区位于震源东北40~120 km, 断层面上的最大位错量约为10 m, 主体滑动分布在2~20 km深度范围, 破裂达到地表; 第二个主体破裂区位于断层破裂带南段, 最大滑动量达到6 m; 另外2个主体滑动区位于断层破裂带北段, 但滑动破裂量小于断层南段破裂区的滑动量, 滑动破裂值最大值为4 m, 超过1 m的区域在走向上超过70 km。 反演得到的断层滑动模型的地震矩为9.5×1021 Nm, 相应的矩震级为MW7.95。 汶川地震破裂表现为单侧破裂, 起始破裂在汶川下方16 km深度, 向东北方向一致性地传播, 过程持续~120 s。 在地震发生后0~10 s内, 破裂集中在震源起始破裂区, 滑动破裂值为~1.0 m, 之后破裂向东北方向扩展, 震后20~40 s是主要的破裂时段。 在40~60 s, 破裂跨越断层南段和北段。 在80~90 s破裂最大值开始下降, 在100~110 s时, 下降为~0.5 m, 在110~120 s时, 下降为~0.1 m。 加入近场GPS测站1-Hz 波形数据与近场强震仪波形和远场长周期体波联合反演, 提高了震源破裂模型的空间分辨率, 特别是浅部滑动破裂区的分辨率, 反演的最大滑动破裂值比不用1-Hz 波形数据反演的结果增大, 表明近场1-Hz GPS波形数据对于揭示汶川地震的时空破裂过程具有重要的作用。 相似文献
9.
The moment tensor solution, source time function and spatial-temporal rupture process of the MS6.4 earthquake, which occurred in Ning’er, Yunnan Province, are obtained by inverting the broadband waveform data of 20 global stations. The inverted result shows that the scalar seismic moment is 5.51×1018 Nm, which corresponds to a moment magnitude of MW 6.4. The correspondent best double couple solution results in two nodal planes of strike 152°/dip 54°/rake 166°, and strike 250°/dip 79°/ rake 37°, respectively... 相似文献
10.
THE SOURCE PARAMETERS AND RUPTURE PROCESS OF THE MW7.0 EARTHQUAKE IN ALASKA,USA ON DECEMBER 1, 2018 
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下载免费PDF全文 XU Zhi-guo ZHANG Huai ZHOU Yuan-ze LIANG Shan-shan SU Zhe SHI Jian-yu ZHAO-Bo 《地震地质》2019,41(5):1223-1238
A magnitude MW7.0 earthquake struck north of Anchorage, Alaska, USA on 1 December 2018. This earthquake occurred in the Alaska-Aleutian subduction zone, on a fault within the subducting Pacific slab rather than on the shallower boundary between the Pacific and North American plates. In order to better understand the earthquake source characteristics and slip distribution of source rupture process as well as to explore the effect of tectonic environment on dynamic triggering of earthquake, the faulting geometry, slip distribution, seismic moment, source time function are estimated from broadband waveforms downloaded from IRIS Data Management Center. We use the regional broadband waveforms to infer the source parameters with ISOLA package and the teleseismic body wave recorded by stations of the Global Seismic Network is employed to conduct slip distribution inversion with iterative deconvolution method. The focal mechanism solution indicates that the Alaska earthquake occurred as the result of tensile-type normal faulting, the estimated centroid depth from waveform inversion shows that the earthquake occurred at the depth of 56.5km, and the centroid location is 10km far away in northeast direction relative to the location of initial epicenter. We use the aftershock distribution to constrain the fault-plane strike of a normal fault to set up the finite fault model, the finite fault inversion shows that the earthquake slip distribution is concentrated mainly on a rectangular area with 30km×20km, and the maximum slip is up to 3.6m. In addition, the slip distribution shows an asymmetrical distribution and the range of possible rupture direction, the direction of rupture extends to the northeast direction, which is same as that of aftershock distribution for a period of ten days after the mainshock. It is interesting to note that a seismic gap appears in the southwest of the seismogenic fault, we initially determined that the earthquake was a typical normal fault-type earthquake that occurred in the back-arc extensional environment of the subduction collision zone between the Pacific plate and the North American plate, this earthquake was not related to tectonic movement of faults near the Earth's surface. Due to the influence of high temperature and pressure during the subduction of the Pacific plate toward to the north, the subduction angle of the Pacific plate becomes steep, causing consequently the backward bending deformation, thus forming to a tensile environment at the trailing edge of the collision zone and generating the MW7.0 earthquake in Alaska. 相似文献
11.
采用欧洲空间局ERS-2的星载干涉雷达数据,选取1997年11月8日MW7.6级玛尼地震作为研究对象,采用了差分干涉方法,在通过对覆盖同一地区的SAR数据进行差分干涉处理,得到了玛尼地震的视线向同震形变场。经研究发现:该地震形变场呈长轴近北东东向不规则椭圆形分布,地表破裂带长度约为130km,发震断层走向约为78°,断裂为左行走滑特征。断层以南为隆起区,在发震断层附近最大视线向隆起位移量为113.6cm,断层以北为沉降区,最大视线向沉降位移量为170.4cm。基于Okada模型实现了具有复杂结构的4段断层段参数的InSAR形变场数据模拟,获得断层的最大走滑为6m,估计出玛尼地震的标量地震矩M0为2.69×10^20Nm,计算得到的矩震级MW为7.6。证明了研究方法的正确性和研究结论的可靠性。 相似文献
12.
2016年1月21日, 青海省门源县冷龙岭断裂带附近发生了MW5.9地震。 基于Sentinel-1A影像, 采用差分干涉雷达测量技术研究了此次地震产生的同震形变场, 结果表明, 门源地震的形变影响范围约20~30 km, 形变态势在升降轨道形变场均显示为隆升, 基本沿冷龙岭断裂呈近似同心圆展布, 推测可能是冷龙岭断裂与民乐—大马营断裂之间的一条逆断层, 沿雷达视线方向最大形变量级约为6 cm。 均匀滑动反演显示门源发震断层长7.3 km, 宽6.2 km, 走向298.6°, 倾角34.5°, 倾向宽度9.5 km, 沿走向滑动量为170 mm, 沿倾向滑动量为460 mm, 矩震级为MW5.97; 分布式滑动反演显示门源地震以逆冲为主, 兼具少量右旋走滑分量, 滑动量主要集中在沿断层倾向方向, 距离地表5～15 km处, 最大滑动量约0.3 m, 位于断层倾向深度10 km处, 矩震级为MW5.93。 相似文献
13.
本文计算并分析了不对称双侧破裂方式的矩形断层辐射的 P 波远场位移谱, 提出研究不对称双侧破裂过程的初步方法, 并将它应用于1975年2月4日辽宁省海城7.3级地震的震源破裂过程的研究.研究结果表明, 海城地震的破裂方式是在震源地区北西西断层上发生的不对称双侧破裂过程, 断层总长度为54公里, 主破裂朝北西西方向, 破裂长度为38公里, 破裂速度为1.3公里/秒, 向南东东方向破裂的长度为16公里, 破裂速度亦为1.3公里/秒.进而求得海城地震的震源参数为:走向滑动平均错距117厘米;倾向滑动平均错距33厘米;地震矩5.2×1026 达因·厘米;应力降22巴;应变降3.3×10-5; 释放的总能量3.4×1022尔格. 相似文献
14.
An earthquake of M
S=7.4 occurred in Mani, Xizang (Tibet), China on November 8, 1997. The moment tensor of this earthquake was inverted using
the long period body waveform data from China Digital Seismograph Network (CDSN). The apparent source time functions (ASTFs)
were retrieved from P and S waves, respectively, using the deconvolution technique in frequency domain, and the tempo-spatial
rupture process on the fault plane was imaged by inverting the azimuth dependent ASTFs from different stations. The result
of the moment tensor inversion indicates that the P and T axes of earthquake-generating stress field were nearly horizontal, with the P axis in the NNE direction (29°), the T axis in the SEE direction (122°) and that the NEE-SWW striking nodal plane and NNW-SSE striking nodal plane are mainly left-lateral
and right-lateral strike-slip, respectively; that this earthquake had a scalar seismic moment of 3.4×1020 N·m, and a moment magnitude of M
W=7.6. Taking the aftershock distribution into account, we proposed that the earthquake rupture occurred in the fault plane
with the strike of 250°, the dip of 88° and the rake of 19°. On the basis of the result of the moment tensor inversion, the
theoretical seismograms were synthesized, and then the ASTFs were retrieved by deconvoving the synthetic seismograms from
the observed seismograms. The ASTFs retrieved from the P and S waves of different stations identically suggested that this
earthquake was of a simple time history, whose ASTF can be approximated with a sine function with the half period of about
10 s. Inverting the azimuth dependent ASTFs from P and S waveforms led to the image showing the tempo-spatial distribution
of the rupture on the fault plane. From the "remembering" snap-shots, the rupture initiated at the western end of the fault,
and then propagated eastward and downward, indicating an overall unilateral rupture. However, the slip distribution is non-uniform,
being made up of three sub-areas, one in the western end, about 10 km deep ("western area"); another about 55 km away from
the western end and about 35 km deep ("eastern area"); the third about 30 km away from the western end and around 40 km deep
("central area"). The total rupture area was around 70 km long and 60 km wide. From the "forgetting" snap-shots, the rupturing
appeared quite complex, with the slip occurring in different position at different time, and the earthquake being of the characteristics
of "healing pulse". Another point we have to stress is that the locations in which the rupture initiated and terminated were
not where the main rupture took place. Eventually, the static slip distribution was calculated, and the largest slip values
of the three sub-areas were 956 cm, 743 cm and 1 060 cm, for the western, eastern and central areas, respectively. From the
slip distribution, the rupture mainly distributed in the fault about 70 km eastern to the epicenter; from the aftershock distribution,
however, the aftershocks were very sparse in the west to the epicenter while densely clustered in the east to the epicenter.
It indicated that the Mani M
S=7.9 earthquake was resulted from the nearly eastward extension of the NEE-SWW to nearly E-W striking fault in the northwestern
Tibetan plateau.
Contribution No. 99FE2016, Institute of Geophysics, China Seismological Bureau.
This work is supported by SSTCC Climb Project 95-S-05 and NSFDYS 49725410. 相似文献
15.
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
16.
Temporal and spatial rupture process of the great Kunlun Mountain Pass earthquake of November 14, 2001 from the GDSN long period waveform data 总被引：7，自引：0，他引：7
XU Lisheng & CHEN Yuntai Institute of Geophysics China Seismological Bureau Beijing China 《中国科学D辑(英文版)》2005,48(1):112-122
The temporal and spatial rupture process of the 14 November 2001 Kunlun Mountain Pass earthquake (KMPE) is obtained by inverting the high signal-to-noise-ratio P-waveform data of vertical components of 20 stations with epicentral distances less than 90°, which are of Global Digital Seismogragh Network (GDSN). The inverted results indicate that the KMPE consists of 3 sub-events. The rupture of the first sub-event initiated at the instrumental epicenter (35.97°N, 90.59°E) and then propagated both westwards and eastwards, extending 140 km westwards at the speed of 4.0 km/s and 80 km eastwards at the speed of 2.2 km/s, which appeared to be an asymmetrical bilateral rupture dominantly from east to west. This sub-event formed a 220-km-long fault. Fifty-two seconds after initiation of the first sub-event, at which time the first sub-event was not over but in its healing phase, the rupture of the second sub-event initiated 220 km west of the epicenter and propagated both westwards and eastwards, extending 50 相似文献
17.
2008年5月12日发生在四川汶川的大地震造成映秀—北川断裂和灌县—江油断裂同时破裂,分别形成了240多公里和70多公里的地表破裂带.本文以GPS观测获得的同震位移场为约束,反演地震破裂的空间分布.反演结果显示映秀—北川主破裂带倾向北西,沿破裂带的走向从南到北倾角逐渐变大,破裂断层的平均宽度在10~18 km左右.破裂断层的错动在南段以逆冲为主,在北段走滑分量逐步加大,右旋走滑成为断层破裂的主要特征.断层破裂最大段落错动量分别达到了7.8 m和7.4 m,恰好对应这次地震中地表破坏最为严重的映秀和北川地区.本次地震释放地震矩6.70×1020N·m,相应矩震级Mw=7.9. 相似文献
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基于中国国家和四川区域数字地震台网记录,采用HypoDD方法精确定位了四川芦山ML2.0级以上地震序列的震源位置,采用CAP方法反演了36次ML4.0级以上地震的最佳双力偶震源机制解,并利用小震分布和区域应力场拟合了可能存在的发震断层面参数,从而综合分析了芦山地震序列的震源深度、震源机制和震源破裂面特征,探讨可能的发震构造.结果显示,7.0级主震的震源位置为30.30°N、102.97°E,初始破裂深度为15 km左右,震源矩心深度为14 km左右,最佳双力偶震源机制解的两组节面分别为走向209°/倾角46°/滑动角94°和走向23°/倾角44°/滑动角86°,可视为纯逆冲型地震破裂,绝大多数ML4.0级以上余震的震源机制也表现出与主震类似的逆冲破裂特征.ML2.0级以上余震序列发生在主震两侧,集中分布的长轴为30 km左右,震源深度主要集中在5～27 km,ML3.5级以上较大余震则集中分布在9～25 km的深度上,并揭示出发震断层倾向北西的特征.利用小震分布和区域应力场拟合得到发震断层参数为走向207°/倾角50°/滑动角92°,绝大多数余震发生在断层面附近10 km左右的区域.综合地震序列分布特征、主震震源深度和已有破裂过程研究结果,可以推测主震破裂过程自初始点沿断层的两侧扩展破裂,南侧破裂比北侧稍长,滑动量主要集中在初始破裂点附近,可能没有破裂到地表.综合本文研究成果、地震烈度分布和现有的科学考察结果,初步推测发震构造为龙门山山前断裂,也不排除主震震中东侧还存在一条未知的基底断裂发震的可能性. 相似文献
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2008年10月6日16时30分(北京时间),西藏自治区拉萨市当雄县发生Ms6.6级地震.震中位于亚东-谷露近南北向裂谷带北段,是该活动构造带近年来发生的一次较大地震.我们利用中国地震台网中心(CENC)和美国地震学联合研究所(IRIS)提供的宽频带地震记录资料,基于点源和有限断层模型,通过波形拟合反演了该地震的震源过程.结果表明,本次地震的发震断层面走向为183.3°,倾角为49.5°,滑动角约为－115°,最大滑动量达130 cm,地震震源的深度为9.6 km,地震的标量地震矩为2.85×1018 N·m,破裂持续时间约10 s.根据地震破裂的几何学和运动学特征,推测该地震主要发生在亚东-谷露南北向裂谷活动构造带内的一个高角度西倾断层上,是一个以拉张为主且有一定的右旋分量的破裂事件,这与青藏高原现今GPS测量所揭示的该地区地壳运动特征基本一致,暗示了青藏高原南部从西向东地表运动从北北东向到南东东向的运动学转变所导致的地壳在近东西方向上的拉张变形特征. 相似文献
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2013年7月22日,在甘肃岷县漳县交界处发生MS6.6地震,地震震中位置靠近临潭—宕昌断裂.本文通过构建有限断层模型,利用国家强震动台网中心提供的12条强地面运动三分量资料,通过波形反演方法来研究这次地震的震源破裂过程.结果显示这次地震是发生在甘东南地区岷县—宕昌断裂带东段附近的一次MW6.1级逆冲兼具左旋走滑破裂事件,最大滑动量约为80cm.发震断层走向及滑动性质与岷县—宕昌断裂吻合,推断本次地震与东昆仑断裂向北的扩展和推挤密切相关,是岷县—宕昌断裂进一步活动的结果. 相似文献