共查询到18条相似文献，搜索用时 203 毫秒
1.
2014年11月22日康定M_S6.3、M_S5.8地震发生在鲜水河断裂带南段的色拉哈段和折多塘段上。主、余震的时空分布,地震蠕变释放曲线以及震后30天地震日频度均显示,2014年康定地震的地震破裂传播和地震能量释放存在鲜明的时空分段性。对比鲜水河断裂带上1960年以来中强地震的构造位置、地震蠕变曲线、围岩特征等可知,鲜水河断裂带上大部分中强地震序列类型均为主余型或是孤立型,只有发生在鲜水河断裂带南端贡嘎山岩体(折多山花岗岩)周边的1972年康定地震(塔公地震)和2014年康定地震为震群型地震。鲜水河断裂带上震群型地震很可能与强硬的新生代贡嘎山岩体有关。由于岩体的阻挡,震级较小的地震能量较小,不足以使地震破裂在岩体内部传播,导致地震能量转而在岩体周围的相对较软弱的岩层内储存、爆发,从而产生震群型地震序列特征。 相似文献
2.
1967年8月30日,曾在我国四川省甘孜藏族自治州炉霍县境内,发生了一次M=6.8级地震.震中位置是北纬31°.6,东经100°.3。地震发生后,立即进行了现场考察,对该地区的地震发展趋势作出了估计。当时若根据康定一甘孜断裂带所作的蠕变曲线估计,则该地区地震能量已基本释放完毕(图 相似文献
3.
本文根据历史地震(Ms6.0)的资料,研究了鲜水河断裂带的地震活动性,并利用断层的位错模式进一步研究该断裂带的应力积累和释放过程.结果表明,该断裂带的强震活动大致以道孚为界,形成北西和南东两个活动地段,呈现南北交替活动的特征.地震能量的这种交替释放似具有准周期性质,Ms7.0级地震的平均复发周期为27.6年.给出该断裂带在三个不同时间段(1700-1811,1816-1967,1816-1982)强震断层作用引起的应力释放图象,讨论了前两个时间段地震应力场对其后发生的第一个大地震的重要影响.计算了1893年以来在断裂带南东段(相对闭锁段)的应力积累,示出相应的最大剪应力和流体静应力等值线图.最后,根据应力积累、附加应力变化、地震活动规律和应变释放曲线特征,估计了鲜水河断裂带的地震趋势.认为在本世纪末,在断裂带南东段的(1)康定-磨西段或(2)道孚-乾宁段或(3)乾宁-康定段将可能发生 Ms=7.40.3地震. 相似文献
4.
5.
本文基于1970年以来的地震目录及四川地区4.0级以上地震的震源机制解资料,分析鲜水河断裂带分段(炉霍段、道符段、康定段、石棉段)的地震活动特征及研究区现代构造应力场,结合深部速度结构,探讨鲜水河断裂带上地震活动频度与龙门山断裂带地震活动的关系及康定地段6.3级地震的孕震环境。结果发现:(1)鲜水河断裂带北段和南段地震活动性存在差异,炉霍段和道孚段的地震活动频度1981年前要高于2000年后,康定段和石棉段的地震活动频度2000年以后高于1981年前;(2)分析地壳P波速度结构发现康定震区西侧川滇块体表现出低速异常,东侧表现出高速异常;(3)对构造应力场的分析结果表明龙门山断裂带主要以NW-SE向挤压为主,鲜水河断裂带构造应力场以NWW-SEE向为主。综合鲜水河断裂带应力场特征、深部速度结构、断层间的相互作用等信息推断,康定M6.3地震的发生与该地区应力积累及深部孕震环境相关,同时由于龙门山断裂带地震活动性影响,导致鲜水河断裂带康定段的能量释放。 相似文献
6.
本文通过历史地震及现今地震活动性的分析、活断层分段理论及地震空区理论的应用、地震平均复发间隔及复发条件概率的估算以及多学科专家综合评估方法的引入，对川西鲜水河－安宁河－则木河断裂和滇东小江断裂带（中－北段）上15个不同段落的地震潜势进行了深入的研究。进一步修正并重新圈绘出位于鲜水河－安宁河－则木河断裂带上的四川省地震重点监视防御区，其范围：北起道孚县的葛卡或者松林口一带，南至西昌市，沿鲜水河－安宁河－则木河主干断裂带展布，全长约350千米。按对未来地震震级估计的不同，该区可分成3段。第1段位于葛卡或松林口至康定之间，震级估计为7±1／4级；第2段位于康定与石棉之间，估计的震级是61／2±1／4；第3段位于石棉至西昌之间，震级估计为7－71／2。此外，研究结果还显示了小江断裂带上的新塘湾和寻甸一嵩明两个段落未来15年内强震发生的概率相对较高。 相似文献
7.
<正>中国地震台网(2022)测定2022年9月5日12时52分四川泸定县(29.59°N, 102.08°E)发生MS6.8地震,震源深度为16 km。本次地震震中位于鲜水河断裂带(徐泰然等,2022),该断裂带北起甘孜东谷附近,向南经过炉霍、道孚、康定一线,至石棉县安顺场一带逐渐消失,全长约350 km,总体走向320°—330°,呈略向北凸出的弧形,与甘孜—玉树断裂共同构成川滇地块的北边界和巴颜喀拉地块的西南边界。鲜水河断裂带作为中国西南山区现今活动强烈的大型左旋走滑断裂带,具有规模大、活动强、地震频度高等特点(陈桂华等,2008)。 相似文献
8.
2014年11月22日16时55分在四川省甘孜藏族自治州康定县发生的6.3级地震,结束了鲜水河断裂带近30多年以来没有较大地震发生的历史,其潜在的地震危险性再次引起国内外地学工作者的关注.为了研究鲜水河断裂带南东段深部孕震环境和探求康定MS6.3地震的成因,本文先利用四川区域数字地震台网和康定地区及周边所布设的流动地震台阵在2009年1月1日至2014年12月5日期间所记录到7397次区域地震事件的99287条P波到时资料,反演得到了鲜水河断裂带南东段上地壳范围内不同深度的三维P波速度结构特征;再对康定震区及周边的重力、航磁数据进行视密度、视磁化强度反演,得到了壳内不同深度密度的横向变化信息和视磁化强度的分布特征;在此基础上综合研究鲜水河断裂带南东段的深部孕震环境.研究结果表明,雅江—九龙一带的低速区与泸定—宝兴高速区的速度结构特征表明了鲜水河断裂带南东段两侧壳内物质存在显著的横向介质差异,康定MS6.3地震发生在该高低速异常区的分界线上;结合康定MS6.3地震的1028个余震序列的精确定位结果可以看出,重新定位后的余震沿着鲜水河断裂带南东段呈条带状分布,且震源深度优势分布层位深度为8~15km,该余震序列的空间分布特征与鲜水河断裂南东段的深部介质条件密切相关.鲜水河断裂带南东段特有的视密度和视磁化强度异常分布特征反映了康定地区东西两侧块体的基底性质存在明显差异,康定—石棉及其以东地区所表现出的磁异常高和重力高的位场特征,反映该区域由强磁性、高密度物质组成,而康定MS6.3地震就发生在康定—石棉重力梯度变化带上、雅安—泸定磁性穹窿区的西边界线上.随着川青块体向南东方向滑移,受到四川盆地西缘边界刚性基底对川青块体的强烈阻挡,加剧了康定—石棉及其以东地区基底岩层的褶皱变形并产生了强烈的应力积累,所积累的应力突然释放导致了康定MS6.3地震的发生,这正是此次鲜水河断裂带南东段康定地区强震孕育和发生的深部构造环境和介质特征.根据本文对鲜水河断裂带南东段深部孕震环境的综合研究成果可知,石棉段处于重磁异常梯级带上且其北东侧表现出的高密度、强磁性和高波速等物性特征有利于区域应力的相对集中,因此,鲜水河断裂带南东段石棉地区的地震活动趋势和地震危险性背景值得进一步关注和研究. 相似文献
9.
根据笔者近年来在鲜水河断裂带考察所取得到的一些实际资料,从该区几次强震所造成的地震地裂缝特征,并以道孚松林口为界,鲜水河断裂带北西、南东两段的地貌特征,初步分析了该断裂带所处的构造应力状态。一、鲜水河断裂带及其地貌表现 (1)鲜水河断裂带的展布鲜水河断裂带北西起自甘孜东谷附近,向南东经炉霍、道孚、乾宁至康定以南,呈北西向直线状断续延伸,长达300余公里(图1)由 相似文献
10.
本文以青藏高原东南缘为研究区域,利用G-R震级能量经验公式和Benioff地震应变能释放曲线,对该区域内1500a以来的历史地震应变能释放进行了系统研究。文中给出了各断裂带和断块区的地震应变能释放周期表及相应的地震活动性分析。分析发现研究区域地震应变能的释放具有东强西弱,南强北弱的特征,整体上各断层断块区的历史地震应变能释放符合准周期模式,某些断层和断块区上的地震周期具有某种程度的同步现象。青藏高原东南缘现今处于大释放期,地震的活动性不能忽视。对局部地区的研究结果显示,安宁河-则木河断裂带、小江断裂带的地震活动性较强,对于这些地区应重点跟踪研究。 相似文献
11.
There was an earthquake swarm of two major events of MS6.3 and MS5.8 on the Xianshuihe fault in November, 2014. The two major earthquakes are both strike-slip events with aftershock zone along NW direction.We have analyzed the characteristics of this earthquake sequence. The b value and the h value show the significant variations in different periods before and after the MS5.8earthquake. Based on the data of historical earthquakes, we also illustrated the moderate-strong seismic activity on the Xianshuihe fault. The Kangding earthquake swarm manifests the seismic activity on Xianshuihe fault may be in the late seismic active period. The occurrence of the Kangding earthquake may be an adjustment of the strong earthquakes on the Xianshuihe fault. The Coulomb failure stress changes caused by the historical earthquakes were also given in this article. The results indicate that the earthquake swarm was encouraged by the historical earthquakes since1893, especially by the MS7.5 Kangding earthquake in1955. The Coulomb failure stress changes also shows the subsequent MS5.8 earthquake was triggered by the MS6.3earthquake. 相似文献
12.
HOLOCENE PALAEOSEISMOLOGIC RECORD AND RUPTURE BEHAVIOR OF LARGE EARTHQUAKES ON THE XIANSHUIHE FAULT 
下载免费PDF全文
下载免费PDF全文 LI Dong-yu CHEN Li-chun LIANG Ming-jian GAO Shuai-po ZENG Di WANG Hu LI Yan-bao 《地震地质》2017,39(4):623-643
The Xianshuihe Fault, the boundary of Bayan Har active tectonic block and Sichuan-Yunnan active tectonic block, is one of the most active fault zones in the world. In the past nearly 300 years, 9 historical earthquakes of magnitude ≥ 7 have been recorded. Since 2008, several catastrophic earthquakes, such as Wenchuan MS8 earthquake, Yushu MS7.1 earthquake and Lushan MS7 earthquake, have occurred on the other Bayan Har block boundary fault zones. However, only the Kangding MS6.3 earthquake in 2014 was documented on the Xianshuihe Fault. Thus, the study of surface deformation and rupture behavior of large earthquakes in the late Quaternary on the Xianshuihe Fault is of fundamental importance for understanding the future seismic risk of this fault, and even the entire western Sichuan region. On the basis of the former work, combined with our detailed geomorphic and geological survey, we excavated a combined trench on the Qianning segment of Xianshuihe fault zone which has a long elapse time. Charcoal and woods in the trench are abundant. 30 samples were dated to constrain the ages of the paleoseismic events. Five events were identified in the past 9 000 years, whose ages are:8070-6395 BC, 5445-5125 BC, 4355-4180 BC, 625-1240 AD and the Qianning earthquake in 1893. The large earthquake recurrence behavior on this segment does not follow the characteristic earthquake recurrence model. The recurrence interval is 1000~2000 years in early period and in turn there is a quiet period of about 5 000 years after 4355-4180 BC event. Then it enters the active period again. Two earthquakes with surface rupture occurred in the past 1000 years and the latest two earthquakes may have lower magnitude. The left-lateral coseismic displacement of the 1893 Qianning earthquake is about 2.9m. 相似文献
13.
SPECTRAL STRUCTURE OF VELOCITY INHOMOGENEITY OF CRUST MEDIUM BELOW THE SOUTHEASTERN MARGIN OF TIBETAN PLATEAU AND ITS ADJACENT REGIONS 下载免费PDF全文
下载免费PDF全文 In this paper we present results of spectral structure of crustal velocity inhomogeneity beneath the southeastern margin of Tibetan plateau and its adjacent region based on the S wave envelope broadening algorithm. The spectral structure of 8~16Hz band is selected to analyze the special character of crustal inhomogeneity and discuss the correlation between strong earthquakes and inhomogeneities. The result shows that strong and complex inhomogeneities of crustal medium are found in the southeastern margin of Tibetan plateau and its adjacent region. In the upper part of upper crust, the strong and small scale inhomogeneities are imaged in the Longmengshan fault zone and the north of the Anninghe fault zone, the weak and large scale inhomogeneites are imaged in the section from Huolu to Daofu of Xianshuihe fault zone and the south of the Anninghe fault zone. In the lower part of upper crust, strong inhomogeneites are found in the Longmengshan fault zone, Lianfeng fault zone, the north of the Anninghe fault zone and the sections from Huolu to Daofu of the Xianshuihe fault zone, weak inhomogeneites are found in the section from Daofu to Kangding of Xianshuihe fault zone. In the middle crust, strong inhomogeneities are observed in the section of the Baoxing to Dujiangyan, the Baoxing to Kangding, and Kangding to Shimian, and weak inhomogeneities are observed in the northwestern section from Huolu to Kangding, and the Lianfeng fault zone. Comparing the medium inhomogeneities with the location of the strong earthquakes, our results suggest existence of high correlation between them. Strong earthquakes are often located in the transitionary zone between the strong and the weak inhomogeneities. The spatial distribution of the strong and the weak medium inhomogeneities may be related to the broken medium from the strong movement of geological tectonic and the heat flow upwelling along active faults induced by frequent tectonic and volcanic activity. 相似文献
14.
本研究基于分层黏弹介质模型,考虑强震或大地震同震位错、震后黏滞松弛及主断层段震间构造应力加载三方面效应,给出1480年以来,川滇菱形块体东边界鲜水河断裂带、安宁河断裂带、则木河断裂带和小江断裂带共20个断层段由三方面效应引起的累积库仑应力变化随时间的演化,分析强震间相互作用和强震发生的应力累积背景,定性分析各断层段的地震危险性.同时,分别采用现今台网地震目录和川滇菱形块体东边界各断层段强震复发间隔两种资料,定量计算2030年各断层段的强震发生概率;并基于摩擦本构理论,将周边强震引起的库仑应力变化量作为应力扰动,修正强震发生概率的计算结果.各断层段累积库仑应力演化的结果表明,鲜水河断裂带中部八美段、色拉哈段及南部磨西段、安宁河断裂带冕宁-西昌段、小江断裂带北部巧家-东川段和南部建水段的累积库仑应力显著增加.修正的强震发生概率计算结果显示,鲜水河断裂带中部八美-色拉哈-康定一带、安宁河断裂带冕宁-西昌段、小江断裂带南部华宁-建水一带强震发生概率较高,地震危险性值得关注.本研究基于库仑应力演化计算定性分析强震危险性的同时,基于摩擦本构律理论,结合地震引起的应力扰动和强震发生背景,定量计算修正的强震发生概率,为川滇菱形块体东边界强震危险地点及中长期发震紧迫程度判定提供方法和依据. 相似文献
15.
2014年11月22日在NW向鲜水河断裂带中南段四川康定县发生M6.3级地震,11月25日在该地震震中东南约10km处再次发生M5.8级地震.基于中国国家数字地震台网和四川区域数字地震台网资料,采用多阶段定位方法对本次康定M6.3级地震序列进行了重新定位;利用gCAP(generalized Cut And Paste)矩张量反演方法获得了M6.3和M5.8级地震的震源机制解与矩心深度,分析了本次地震序列的发震构造,并结合历史强震破裂时空分布和2001年以来小震重新定位结果,对鲜水河断裂带中段强震危险性进行了初步探讨.获得的主要结果如下:(1)M6.3级主震震中位于101.69°E、30.27°N,震源初始破裂深度约10km,矩心深度9km;M5.8级地震震中位于101.73°E、30.18°N,初始破裂深度约11km,矩心深度9km.gCAP矩张量反演结果揭示这两次地震双力偶分量占主导,M6.3级地震的最佳双力偶解节面Ⅰ走向143°/倾角82°/滑动角-9°,节面Ⅱ走向234°/倾角81°/滑动角-172°.M5.8级地震最佳双力偶解节面Ⅰ走向151°/倾角83°/滑动角-6°,节面Ⅱ走向242°/倾角84°/滑动角-173°.依据余震分布长轴展布与断裂走向,判定节面Ⅰ为发震断层面,M6.3和M5.8级地震均为带有微小正断分量的左旋走滑型地震.(2)序列中重新定位的459个地震平均震源深度约9km,地震主要集中分布在6~11km深度区间,余震基本发生在M6.3和M5.8级地震震源上部.依据余震密集区展布范围,推测本次康定地震的震源体尺度长约30km、宽约4km、深度范围约6km.M6.3级主震震源附近的余震稀疏区可能是一个较大的凹凸体(asperity),在主震中能量得以充分释放.(3)最初3天的余震主要分布在M6.3级地震NW侧;而M5.8级地震之后的余震主要集中在其震中附近.M6.3级地震以及最初3天的绝大部分余震发生在倾角约82°近直立的NW走向色拉哈断裂上;M5.8级地震与其后的多数余震发生在倾角约83°近直立的NW走向折多塘断裂北端走向向北偏转部位,M5.8级地震可能是M6.3级地震触发相邻的折多塘断裂活动所致.(4)康定M6.3与M5.8级地震发生在鲜水河断裂带乾宁与康定之间的色拉哈强震破裂空段,本次地震破裂尺度较小,尚不足以填补该强震空段.色拉哈段以及相邻的乾宁段7级地震平静时间均已超过其平均复发周期估值,未来几年存在发生7级地震的危险.康定M6.3级地震序列基本填补了震前存在于塔公与康定之间的深部小震空区,未来强震发生在塔公至松林口段深部小震稀疏区内的可能性很大. 相似文献
16.
利用断裂带上的低b值识别凹凸体方法的探讨——以龙门山断裂带和鲜水河断裂带为例 总被引：2，自引：1，他引：1
本文对龙门山断裂带和鲜水河断裂带上1970年以来记录的小震数据进行了收集、整理和分析,采用基于Matlab平台的Zmap软件,去除了断裂带上的丛集数据和余震,划定了有效地震数据的时间和震级范围,通过最大似然法求取了断裂带所在区域的b值分布图。基于b值大小与应力高低成反比的原理,通过断裂带上低b值区识别凹凸体的位置。就龙门山断裂带,通过低b值区识别出的凹凸体的位置与汶川地震发生的起始破裂位置和极震区的位置基本保持一致;而鲜水河断裂带由于受到小震数据的限制,部分段缺失b值分布,但整条断裂带仍可清晰识别出凹凸体位置,且1725年以来的历史强震和1970年以来5级以上的历史地震基本上都位于此区域。断裂带的实例分析结果证明,利用小震数据通过最大似然法计算b值分布图,其相对低b值区与历年强震发生的位置存在较大的相关性,为验证利用低b值区识别凹凸体方法的可行性和实用性提供了有力的证据。 相似文献
17.
LATE-QUATERNARY ACTIVITY OF THE YALAHE FAULT OF THE XIANSHUIHE FAULT ZONE,EASTERN MARGIN OF THE TIBET PLATEAU 下载免费PDF全文
下载免费PDF全文 LIANG Ming-jian CHEN Li-chun RAN Yong-kang LI Yan-bao WANG Dong GAO Shuai-po HAN Ming-ming ZENG Di 《地震地质》1979,42(2):513-525
Complex geometrical structures on strike-slip faults would likely affect fault behavior such as strain accumulation and distribution, seismic rupture process, etc. The Xianshuihe Fault has been considered to be a Holocene active strike-slip fault with a high horizontal slip rate along the eastern margin of the Tibetan plateau. During the past 300 years, the Xianshuihe Fault produced 8 earthquakes with magnitude≥7 along the whole fault and showed strong activities of large earthquakes. Taking the Huiyuansi Basin as a structure boundary, the northwestern and southeastern segments of the Xianshuihe Fault show different characteristics. The northwestern segment, consisting of the Luhuo, Daofu and Qianning sections, shows a left-stepping en echelon pattern by simple fault strands. However, the southeastern segment(Huiyuansi-Kangding segment)has a complex structure and is divided into three sub-faults: the Yalahe, Selaha and Zheduotang Faults. To the south of Kangding County, the Moxi segment of the Xianshuihe Fault shows a simple structure. The previous studies suggest that the three sub-faults(the Yalahe, Selaha and Zheduotang Faults of the Huiyuansi-Kangding segment)unevenly distribute the strain of the northwestern segment of the Xianshuihe Fault. However, the disagreement of the new activity of the Yalahe Fault limits the understanding of the strain distribution model of the Huiyuansi-Kangding segment. Most scholars believed that the Yalahe Fault is a Holocene active fault. However, Zhang et al.(2017)used low-temperature thermochronology to study the cooling history of the Gongga rock mass, and suggested that the Yalahe Fault is now inactive and the latest activity of the Xianshuihe Fault has moved westward over the Selaha Fault. The Yalahe Fault is the only segment of the Xianshuihe Fault that lacks records of the strong historical earthquakes. Moreover, the Yalahe Fault is located in the alpine valley area, and the previous traffic conditions were very bad. Thus, the previous research on fault activity of the fault relied mainly on the interpretation of remote sensing, and the uncertainty was relatively large. Through remote sensing and field investigation, we found the geological and geomorphological evidence for Holocene activity of the Yalahe Fault. Moreover, we found a well-preserved seismic surface rupture zone with a length of about 10km near the Yariacuo and the co-seismic offsets of the earthquake are about 2.5~3.5m. In addition, we also advance the new active fault track of the Yalahe Fault to Yala Town near Kangding County. In Wangmu and Yala Town, we found the geological evidence for the latest fault activity that the Holocene alluvial fans were dislocated by the fault. These evidences suggest that the Yalahe Fault is a Holocene active fault, and has the seismogenic tectonic condition to produce a large earthquake, just like the Selaha and Zheduotang Faults. These also provide seismic geological evidence for the strain distribution model of the Kangding-Huiyuansi segment of the Xianshuihe Fault. 相似文献
18.
鲜水河断裂的几何形态对地震发生的影响 总被引：2，自引：2，他引：0
本文整理分析了鲜水河断裂的几何特征以及从1327年有记录以来6级以上历史地震的断层破裂位置和长度。选用速率和状态依赖性摩擦本构关系代表断裂区域物理性质,构建了鲜水河断裂3D物理模型模拟强震周期性。模拟结果与历史地震的发震有较好的一致性,主要表现在:1模拟结果在第二次地震周期之后,明显出现分段现象与鲜水河断裂分段的几何特征较为一致;2断裂北西端结构较为简单,地震发震情况也偏单一,在7级以上地震发震之前有6级以上地震的发生,此类现象与模拟结果一致;3断裂中段结构复杂,不仅存在分段还有轻度弯曲,模拟结果显示中段地震逐渐减小,破裂长度逐步缩短,并且出现级联破裂现象与历史地震较为吻合;43D模拟结果中,地震破裂区域起始与终止位置大都发生在断层转折的区域,特别是在乾宁和康定两处断层出现弯曲的位置,这与鲜水河断裂历史地震发震情况十分相似。 相似文献