Preliminary analysis on characteristics of coseismic deformation associated with <Emphasis Type="Italic">M</Emphasis><Subscript>S</Subscript>=8.1 western Kunlunshan Pass earthquake in 2001

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.     

Preliminary analysis on characteristics of coseismic deformation associated with M S=8.1 western Kunlunshan Pass earthquake in 2001

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.     

2015年新疆皮山MW6.4地震发震断层和滑动分布反演

本文基于Sentinel-1A卫星影像数据提取了2015年皮山M_W6.4地震的同震形变场, 震中北部以隆升为主, 最大抬升量为12.9 cm; 南部以沉降为主, 最大沉降量为5.5 cm。 采用基于单一断层滑动模型的多峰粒子群优化和蒙特卡罗算法, 以LOS向InSAR形变场为约束, 对发震断层的几何模型进行非线性反演。 在此基础上, 联合InSAR和GPS数据, 利用最速下降法反演断层滑动分布。 综合结果表明: 发震断层是顶部埋深约7.4 km的隐伏断裂, 断层面大小为48 km×35 km, 断层走向、 倾角、 断层滑动角分别为111°、 19°、 91°; 断层最大滑动量0.47 m, 位于深度为10.6 km的区域; 累计地震矩3.89×10¹⁸ N·m, 约合矩震级M_W6.33。 最后, 依据主震断层滑移量计算了主震对周围中小断裂的库仑应力扰动变化, 结果显示距离震中最近的泽普断裂受主震影响的库仑应力明显增加; 震后3年内余震集中分布在泽普断裂库仑应力增加区域, 表明皮山地震主震对余震的发生可能具有一定的应力触发作用。     

The seismotectonic and macroseismic features of the Wenchuan (Sichuan) earthquake (<Emphasis Type="Italic">M</Emphasis><Subscript><Emphasis Type="Italic">S</Emphasis></Subscript> = 8.0) of May 12, 2008

A disastrous earthquake with a magnitude M _S = 8.0 (M _W = 7.9), in China called “the 5.12 Wenchuan earthquake,” occurred on May 12, 2008, in Sichuan province on the border between the Sino-Tibetan Mountains and the Sichuan depression. The instrumental epicenter was registered in the southeastern part of Wenchuan county, and the hypocenter depth was 14 km. As the strongest and most destructive earthquake within mainland China, it caused numerous human losses and destruction of buildings and infrastructure. The seismic effect from the main shock and aftershocks was felt in many counties, towns, and villages, though Sichuan province suffered the most. The maximum intensity of the shocks was estimated at 11 degrees, according to the Chinese macroseismic scale. In the process of source opening, from the southern part of Wenchuan county to the vicinities of Quingchuan, a seismic fault system with a total length up to 240 km out-cropped on the earth’s surface, confined to the Longmenshan fault belt. The seismic fault system disturbed the original ground, resulting in the collapse or damage to various constructions, such as buildings, homes, bridges, roads, etc. Fault offsets had a dextral strike-slip and thrust kinematic combination. The earthquake generated several tens of thousands of landslides, rockfalls, and debris flows. Many dammed ponds appeared in the epicentral zone due to the activation of landslides. Thus, the geological effects turned out to be the most destructive factor in this case. At the same time, the seismic intensity of surface shaking was abnormally low even in direct proximity to the seismic fault system. Usually it was no more than 7–8 degrees. This macroseismic phenomenon may turn out to be rather typical for many major earthquakes.     

Coseismic displacement estimate of the 2013 <Emphasis Type="Italic">M</Emphasis><Subscript>S</Subscript>7.0 Lushan,China earthquake based on the simulation of near-fault displacement field

Usually, GPS observation provides direct evidence to estimate coseismic displacement. However, GPS stations are scattered, sparse and cannot provide a detailed distribution of coseismic displacement. Strong ground motion records share the same disadvantages as GPS in estimating coseismic displacement. Estimations from InSAR data can provide displacement distributions; however, the resolution of such methods is limited by the analysis techniques. The paper focuses on estimating the coseismic displacement of the M _S7.0 Lushan earthquake on April 20, 2013 using a simulation of the wave field based on the elastic wave equation instead of a quasi-static equation. First, the media and source models were constructed by comparing the simulated velocity and the record velocity of the ground motion. Then simulated static displacements were compared with GPS records. Their agreement validates our results. Careful analysis of the distribution of simulated coseismic displacements near the fault reveals more details of the ground motion. For example, an uplift appears on the hanging wall of the fault, rotation is associated with the horizontal displacement, the fault strike and earthquake epicenter provide the main control on motion near the faults, and the motion on the hanging wall is stronger than that on the footwall. These results reveal additional characteristics of the ground motion of the Lushan earthquake.     

2001年昆仑山口西8.1级地震同震形变场特征的初步分析a

利用差分干涉雷达测量技术获取的宏观震中区的同震形变场，结合对地震活动性、震源机制、野外考察等资料分析，对昆仑山口西8.1级地震同震形变场特征进行了研究. 结果表明:宏观震中位于库赛湖东北侧，宏观震中区发震断层可分为两个形变中心区域，其中西段长约42 km，东段长约48 km，整个发震断层主破裂段长90 km；由干涉形变条纹分布格局可清楚地判断出发震断层的左旋走滑特征；断层两盘变形特征不同，南盘变形程度明显大于北盘；宏观震中附近最大斜距向位移量为288.4 cm，最小斜距向位移量为224.0 cm，宏观震中发震断层最大左旋水平位错为738.1 cm，最小地面左旋水平位错为551.8 cm.      

Preliminary analysis on characteristics of coseismic deformation associated with M_S=8.1 western Kunlunshan Pass earthquake in 2001

IntroductionOnNovember14,2001,aMS=8.1earthquakeoccurredonthewestofKunlunshanPassintheborderareaofQinghaiandXinjiang,whichwasthestrongestearthquakeinChinesemainlandsincetheMS=8.0earthquakeoccurredinDangxiongdistrictofXizangAutonomousRegiononNovember18,1951.TheearthquakeoccurredontheEasternKunlunTectonicZone,whichwasapalaeoplatejunctionzoneinsideTibetanPlateau.ItdividedTibetanPlateauintothesouthandnorthparts.ThezoneplayedaveryimportantroleinTibetanPlateausdeformationprocessanddynamicev…     

Frequency-dependent rupture process,stress change,and seismogenic mechanism of the 25 April 2015 Nepal Gorkha <Emphasis Type="Italic">M</Emphasis><Subscript>w</Subscript> 7.8 earthquake

On 25 April 2015, an M _w 7.8 earthquake occurred on the Main Himalaya Thrust fault with a dip angle of ~ 7° about 77 km northwest of Kathmandu, Nepal. This Nepal Gorkha event is the largest one on the Himalayan thrust belt since 1950. Here we use the compressive sensing method in the frequency domain to track the seismic radiation and rupture process of this event using teleseismic P waves recorded by array stations in North America. We also compute the distribution of static shear stress changes on the fault plane from a coseismic slip model. Our results indicate a dominant east-southeastward unilateral rupture process from the epicenter with an average rupture speed of ~3 km s^?1. Coseismic radiation of this earthquake shows clear frequency-dependent features. The lower frequency (0.05–0.3 Hz) radiation mainly originates from large coseismic slip regions with negative coseismic shear stress changes. In comparison, higher frequency (0.3–0.6 Hz) radiation appears to be from the down-dip part around the margin of large slip areas, which has been loaded and presents positive coseismic shear stress changes. We propose an asperity model to interpret this Nepal earthquake sequence and compare the frequency-dependent coseismic radiation with that in subduction zones. Such frequency-dependent radiation indicates the depth-varying frictional properties on the plate interface of the Nepal section in the main Himalaya thrust system, similar to previous findings in oceanic subduction zones. Our findings provide further evidence of the spatial correlation between changes of static stress status on the fault plane and the observed frequency-dependent coseismic radiation during large earthquakes. Our results show that the frequency-dependent coseismic radiation is not only found for megathrust earthquakes in the oceanic subduction environment, but also holds true for thrust events in the continental collision zone.     

Mechanism of the M<Subscript><Emphasis Type="Italic">L</Emphasis></Subscript>4.0 25 April 2016 earthquake in southwest of France in the vicinity of the Lacq gas field

The source mechanism of the M_L 4.0 25 April 2016 Lacq earthquake (Aquitaine Basin, South-West France) is analyzed from the available public data and discussed with respect to the geometry of the nearby Lacq gas field. It is one of the biggest earthquakes in the area in the past few decades of gas extraction and the biggest after the end of gas exploitation in 2013. The routinely obtained location shows its hypocenter position inside the gas reservoir. We first analyze its focal mechanism through regional broad-band seismograms recorded in a radius of about 50 km epicentral distances and obtain EW running normal faulting above the reservoir. While the solution is stable using regional data only, we observe a large discrepancy between the recorded data on nearby station URDF and the forward modeling up to 1 Hz. We then look for the best epicenter position through performing wave propagation simulations and constraining the potential source area by the peak ground velocity (PGV). The resulting epicentral position is a few to several km away to the north or south direction with respect to station URDF such that the simulated particle motions are consistent with the observation. The initial motion of the seismograms shows that the epicenter position in the north from URDF is preferable, indicating the north-east of the Lacq reservoir. This study is an application of full waveform simulations and characterization of near-field ground motion in terms of an engineering factor such as PGV. The finally obtained solution gives a moment magnitude of M_w 3.9 and the best focal depth of 4 km, which corresponds to the crust above the reservoir rather than its interior. This position is consistent with the tendency of Coulomb stress change due to a compaction at 5 km depth in the crust. Therefore, this earthquake can be interpreted as a relaxation of the shallow crust due to a deeper gas reservoir compaction so that the occurrence of similar events cannot be excluded in the near future. It would be necessary to continue monitoring such local induced seismicity in order to better understand the reservoir/overburden behavior and better assess the local seismic hazard even after the end of gas exploitation.     

Updating the Probabilistic Seismic Hazard Values of Northern Algeria with the 21 May 2003 <Emphasis Type="Italic">M</Emphasis> 6.8 Algiers Earthquake Included

The occurrence of the Algiers earthquake (M 6.8) of May 21, 2003, has motivated the necessity to reassess the probabilistic seismic hazard of northern Algeria. The fact that this destructive earthquake took place in an area where there was no evidence of previous significant earthquakes, neither instrumental nor historical, strongly encourages us to review the seismic hazard map of this region. Recently, the probabilistic seismic hazard of northern Algeria was computed using the spatially smoothed seismicity methodology. The catalog used in the previous computation was updated for this review, and not only includes information until June 2003, but also considers a recent re-evaluation of several historical earthquakes. In this paper, the same methodology and seismicity models are utilized in an effort to compare this methodology against an improved and updated seismic catalog. The largest mean peak ground acceleration (PGA) values are obtained in northernmost Algeria, specifically in the central area of the Tell Atlas. These values are of the order of 0.48 g for a return period of 475 years. In the City of Algiers, the capital of Algeria, and approximately 50 km from the reported epicenter of this latest destructive earthquake, a new mean PGA value of 0.23 g is obtained for the same return period. This value is 0.07 g greater than that obtained in the previous computation. In general, we receive greater seismic hazard results in the surrounding area of Algiers, especially to the southwest. The main reason is not this recent earthquake by itself, but the significant increase in the m_max magnitude in the seismic source where the city and the epicenter are included.     

Attempt to identify seismic sources in the eastern Mitidja basin using gravity data and aftershock sequence of the Boumerdes (May 21, 2003; Algeria) earthquake

In order to try to identify the seismogenic sources in the epicentral area, we interpreted data collected from gravity and aftershocks in the eastern part of the Mitidja basin after the occurrence of the 21 May 2003 Boumerdes earthquake (Mw = 6.8). The residual gravity anomaly and the horizontal gradient maps revealed the basement shape and density discontinuities. A seismotectonic model obtained from the aftershocks distribution and gravity data is proposed. This model highlights three active faults: one offshore and two onshore. The offshore reverse fault striking NE-SW, parallel to the coast, is consistent with the USGS focal mechanism of the main event, which is assumed to have the most moment release. The two onshore dipping blind active faults are postulated at crossing angles near the SW tip of the main fault. The interpretation is based mainly on the re-location and distribution of aftershocks, and their focal solutions. It is also supported by the basin structures obtained from the inversion and interpretation of residual gravity anomalies, as well as by additional compiled information such as the pattern of coastal co-seismic uplift. This configuration puts forward the failure mode complexity during the main shock. The topography of the basement obtained from 3D gravity inversion shows that all the onshore located aftershocks occurred in the basement, and the area between the two onshore faults rose as a consequence of their sliding.     

2017年九寨沟MS7.0地震对周围地区的静态应力影响

基于九寨沟M_S7.0地震的破裂模型及均匀弹性半空间模型,本文计算了该地震在周围主要活动断层上产生的库仑应力变化、在周围地区产生的应力场和位移场和同震库仑应力变化对余震的触发.结果表明：（1）九寨沟地震造成虎牙断裂中段库仑破裂应力有较大增加,已经超过0.01 MPa的阈值,虎牙断裂北段、塔藏断裂中段和岷江断裂北段北部的库仑破裂应力有较大降低,因此尤其要注意虎牙断裂中段的危险性.（2）水平面应力场在该地震震中东西两侧增加（拉张）,张应力起主要作用.在震中南北两侧降低（压缩）,压应力起主要作用.从水平主压和主张应力方向来看,均呈现出条形磁铁的磁场形态.从剖面上的应力场来看,在上盘的面膨胀区域内,大部分点的主张应力方向与地表是垂直的,在其他区域内,主张应力和主压应力均以震中为中心,向外呈辐射状.（3）从地表水平位移场来看,震中东西两侧物质朝震中位置汇聚,南北两侧物质向外流出,在震中处的最大水平位移量达43 mm.从地表垂直位移场来看,震中南北两侧出现明显的隆升,隆升最大值达56.8 mm.震中东西两侧出现明显的沉降,沉降最大值达74.5 mm.从剖面的位移场来看,九寨沟地震为左旋走滑地震,且有一定的正断成分.由分析可以推测该断层破裂在大致22~26 km的深度上就截止了.并推测下盘物质运动的动力来自震源北东东方向（四川块体）深度在6~30 km的下盘下层物质,上盘物质运动的动力来自震源北西西方向（巴颜喀拉块体）深度在0~6 km的上盘上层物质.（4）通过计算不同深度上主震对余震的触发作用可知,主震后的最大余震受到了主震的触发作用,多数其他余震也受到主震的触发作用.主震的发生促使了库仑应力增加地区余震的发生,抑制了一部分库仑应力减少地区余震的发生.     

The aftershock sequence of the 5 August 2014 Orkney earthquake (M<Subscript>L</Subscript> 5.5), South Africa

More than 1000 aftershocks were recorded within a month after the occurrence of the M_L 5.5, 5 August 2014 Orkney earthquake. The events were relocated using the double difference method as part of an effort to identify the fault which might be the source of the events. A north–south trend of seismicity was revealed by the relocated events, with a diffuse cluster to the north of the main event. A depth profile shows these two clusters: one at a depth of about 2 km to the north of the main event and the other at depth between 3 and 6 km south of the main event. Focal mechanism solutions of 18 aftershocks were determined using first motion polarities from seismic stations of the Council for Geoscience cluster networks. Stress inversion analysis results from the focal mechanism solutions show a dominant extensional stress field in the region; the main event had a strike-slip fault plane solution. This is consistent with the regional stress field which is predominantly related to the East African rift system. It is possible that the occurrence of the main event triggered seismicity on shallower faults within the mining horizons oriented in a different direction to the fault on which the main event occurred. The area has a complex heterogeneous faulting structure as indicated by the observed low p values and complex focal mechanism solutions.     

Analysis of the 1997 Zirkuh (Ghean-Birjand) aftershock sequence in east-central Iran

IntroductionThesouthernpartofKhorasanProvinceineast-centralIranisoneoftheseismicallyactiveregionsintheMiddleeast.Historicalreportsindicatedseveralearthquakeshavecausedseveredestructionsandhumanlossinthisregionduringthepastcenturies(Ambraseys,Melville,1982).Theinstrumentallyrecordedearthquakesaswellastheexistenceofseveralactivefaultsalsosug-gestedthattheregionhadahighpotentialofseismicactivities.OnMay10,1997at07:57:29.6GMT,12:27:29.6localtime,ashallowdestructiveearthquakewithoutanyfeltfores…     

The Beni-Ourtilane-Tachaouaft fault and Seismotectonic aspects of the Babors region (NE of Algeria)

A shallow moderate (M _s=5.7) but damaging earthquake shook theregion of Beni-Ourtilane located about 50 km NW of Setif and 390 kmNE of Algiers (Central Eastern Algeria). The main shock caused the deathof 2 peoples, injured 50 and caused sustainable damage to about 3000housing units. The main shock was preceded by 2 foreshocks and followedby many aftershocks which lasted for many days. Analysis of historicalseismicity including the localisation of epicenters, the trend of isoseismalmaps of some historical events, the localisation of the November 10, 2000main shock (M _s=5.7) and the November 16, 2000 aftershock(M _s=4.5) as well as the shape of the area of maximum intensity ofthe November 10, 2000 earthquake suggest that the Tachaouaft fault of20 km of length is the activated geological structure. Although, there isno clear surface breaks associated with this earthquake, the localisation ofgeological disorders, such as ground fissures, during the Beni-Ourtilaneearthquake, which are remarkably located near the fault, may have atectonic meaning. Geomorphological analysis through Digital ElevationModels (DEMs) allowed us to identify a clear fault scarp related likely tostrong earthquakes occurred in the past. Among geomorphologicalevidences of this active fault there are the uplift and tilt of alluvial terraceson the hanging wall and the diversion of the drainage pattern. Based onthe quality of constructions and field observations an intensity I ₀ = VII (MSK scale) is attributed to the epicentral area,which is striking NE-SW in agreement with the focal mechanism solutionand the seismotectonic observations. In the other hand the amount ofdamage is due rather to the bad quality of constructions than to theseverity of ground motion. The Tachaouaft fault with the Kherrata fault isthe main source of seismic hazard in the Babors region.     

Evidence for a seafloor rupture of the Carboneras Fault Zone (southern Spain): Relation to the 1522 Almería earthquake?

High-resolution sea floor imaging (narrow beam sediment profiler) yields evidence for an offshore rupture along a strand of the Carboneras Fault Zone (CFZ) in the Gulf of Almería off southern Spain. The observed faults affect the seafloor and cut the Late Holocene sedimentary cover, hence the faults are regarded as active and the escarpments as relatively fresh. Seafloor faulting is associated with escarpments, fissures, pressure ridges, folds, and reverse faults indicating sinistral strike-slip faulting with a significant vertical displacement. Adjacent to the major fault zone secondary phenomena such as submarine slumps and slides are observed. The observed fresh escarpments imply an offshore rupture during a major earthquake along the CFZ. The southern Iberian margin and the Afro-Eurasian convergence zone form an area of moderate seismicity. However, some major events occurred, such as the 1522 Almería earthquake (EMS IX; [IGN (2005) Instituto Geografico Nacional, www.ign.es]), which affected large areas in the western Mediterranean. Different epicentral areas have been suspected, mainly along the 50 km long sinistral CFZ; however, no on-shore surface ruptures and paleoseismological evidences for this event have been found. Based on our data, a new epicentral area is proposed in the Gulf of Almería precisely along the observed sea floor rupture area, where the CFZ extend at least for 100 km offshore. Our findings suggest a specific seismic hazards and tsunami potential for offshore active and seismogenic faults in the Alborán Sea.     

基于GPS观测分析日本9.0级地震同震位错与近场形变特征

2011年3月11日日本本州宫城县东海岸近海发生Mw9.0级地震,本文在对GPS同震位移场分布及误差特征分析的基础上,反演了同震位错分布.误差分析结果表明震源北西向300 km、北北西向550 km、南西向700 km范围内的同震位移量值明显大于误差,可以为位错反演提供有效的地表位移约束.沿震源北西向GPS剖面结果和位...     

23 October 2011 Van, Eastern Anatolia, earthquake (M W 7.1) and seismotectonics of Lake Van area

The 23 October 2011 Van earthquake took place in the NE part of Lake Van area, surprisingly on a fault (the Van fault) that is not present in the current active fault map of Turkey. However, occurrence of such a large magnitude earthquake in the area is not surprising regarding the historical seismicity of the region. The comparison of the damage patterns suggests that the earthquake is much likely a recurrence of the 1715 Van earthquake. The finite fault modelling of the earthquake using teleseismic broadband body waveforms has shown that the earthquake rupture was unilateral toward SW, was mostly reverse faulting, confined to below the depth of 5 km, did not propagate offshore, and was dominated by a failure of a single asperity with a peak slip of about 5.5 m. The total seismic moment calculated for the model is 4.6?×?10¹⁹ Nm (M _W ?≈?7.1). The finite fault model coincides with the field observations indicating blind faulting and the vertical displacements over the free surface estimated from it correlate well with the maximum reported uplift along the coast of Lake Van above the hanging wall. The possible offshore continuations of the Van fault and some other faults lying its south are also discussed by assessing a previous offshore seismic reflection study and the earthquake epicentres and focal mechanisms.     

Deep electrical anomaly in the <Emphasis Type="Italic">M</Emphasis>7.5 Qiongzhou earthquake region and its relation with future seismicity

From the magnetotelluric detection in the epicentral region and the adjacent areas of the 1605 M7.5 Qiongzhou earthquake, we have discovered there is a low resistive body in the deep crust of the epicentral region. The low resistive body extends straightly from the depth of about 13 km to the upper mantle, which is supposed as an uprising mantle pole. We therefore consider it is just the existing mantle pole and its upwelling thermal material that result in the faulting and stick-slipping activities of the upper crust, which is an important factor for the M7.5 Qiongzhou great earthquake occurrence. The postseismic faulting activity is characterized by creep, which shows that the risk is greatly decreased for the occurrence of a great earthquake with similar intensity in the future.     

尼泊尔M_W7.8地震InSAR同震形变场及断层滑动分布

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.