共查询到19条相似文献,搜索用时 46 毫秒
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西秦岭北缘断裂带特征地震平均复发间隔的确定和地震危险性评价 总被引:9,自引:1,他引:9
时间相依的地震危险性概率评估方法是最近10a来逐渐发展起来的,是一种将已获得的定量地质资料运用于活动断裂中—长期地震潜势概率评估的方法,从而使得在缺乏历史记载或仪器记录资料,但已获得断层平均滑动速率、同震位错、古地震年代序列等资料的活动断裂段上评估未来的发震概率成为可能。在定量计算活动断裂未来地震危险性的过程中,作为输入参数之一的特征地震平均复发间隔是一个至关重要的参数,它的确定将直接影响到概率计算的结果。对研究断裂上已获得的历史地震资料(H)、地质资料(G)和古地震资料(P),笔采用了时间可预报(T)和准周期(Q)两种模式分别计算其平均复发间隔,比单一的只假定一种复发模式计算更具有完善性和可靠性。在叙述该方法的同时,以西秦岭北缘断裂为例,详细阐述了该断裂上特征地震平均复发间隔的确定,并在此基础上对西秦岭北缘断裂未来地震潜势作了定量评估。 相似文献
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西秦岭北缘断裂带的位移累积滑动亏损特征及其破裂分段性研究 总被引:5,自引:3,他引:2
根据西秦岭北缘断裂带的水平位移分组特征,定量计算了断裂端部和不连续部位的位移累积滑动亏损率,同时结合断裂带上的障碍体规模,滑动速率的差异,历史地震及古地震特征等,对断裂带进行了破裂分段性研究,结果表明,西秦岭北缘断裂带可以划分为鸳凤断裂,漳县断裂,锅麻滩断裂3条一级破裂段,6条二级破裂段。 相似文献
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西秦岭北缘断裂带地震活动特征及近期发展趋势 总被引:1,自引:0,他引:1
本文讨论了西秦岭北缘断裂带在青藏高原东北部三次地震活动高潮幕和两次地震活动低潮幕中的作用和特点,以及地震活动的时空强特征和近期发展趋势。 相似文献
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西秦岭北缘断裂带是青藏高原东北缘一条强烈活动的Ⅱ级块体边界断裂,曾发生过多次6.5级以上大震。规划中的西宁至成都铁路设计线路拟从甘家盆地一带穿行,西秦岭北缘断裂带西段的活动性及其端部终止位置,直接关系到铁路安全。基于甘家盆地一带的第四纪地质地貌与断裂活动性调查结果 ,对西秦岭北缘断裂带的西端活动性及其对铁路方案的影响进行了分析和讨论。结果显示:西秦岭北缘断裂带西段发散为两条主要活动断层,均有全新世地表弱活动迹象;断裂西端终止于甘家盆地东缘一带,铁路设计方案在甘家盆地一带未直接穿经西秦岭北缘断裂带,未来遭遇突发位错的可能性不大,但需要考虑该断裂可能产生的地震动影响。 相似文献
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龙陵 -澜沧新生断裂带的地震活动具频度高、强度大、周期短等特征 ,并以双震或震群型为主。断裂带由多条次级新生断层组成 ,呈斜列或共轭式展布 ,根据结构、规模、地震活动差异等因素把断裂带划分为 4个一级段、13个二级段 ,其中有 4个二级段又可划分出 8个三级段。历史上发生过大震、强震并有地震断层伴生的断层段为地震破裂单元 ;断裂带上晚第四纪有活动并有古地震事件 ,但无历史地震记载的地段为断层闭锁单元 ;次级断层之间的阶区或连接点为障碍体单元。从地震破裂特征分析 ,断裂带由破裂、闭锁、障碍体单元组成 ,根据地震、古地震、活断层、断层阶区的活动规律 ,断裂带可划分出 9个破裂单元、8个闭锁单元、10个障碍体单元。三者之间呈迁移、触发和转换能量的关系。根据这些关系和地震构造标志 ,对断裂带上未来可能发生大震、强震、中强震的地区分别作了预测。预测的危险区有 9个 ,其中大震区 1个 (永康 -永德地区 ) ,强震区 3个 (马站、石灰窑、酒房-勐混 ) ,中强震区 5个 (下顺江、里仁、大岗山、南明 -澜沧、勐遮 相似文献
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论延庆盆地北缘断裂带的分段与地震预测 总被引:4,自引:4,他引:4
依据古地震学的断层习性资料,提出延庆盆地北缘断裂带5个段落的分段模型。各个段落的构造地貌学特征具有明显差异。4个主要不连续性形成段落边界:断层分叉和断层弯曲是非持久性段落边界,而凸出体和雁行断错是持久性段落边界。预期强震(M≥7)的发生时间在未来1000~2000a内,最有可能的地点为断层段落Ⅱ。 相似文献
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西秦岭北缘断裂带是青藏高原东北部一条左旋走滑为主的活动断裂带,其在黄香沟一段活动性较强,活动现象典型。对沿断裂带分布的地貌、地质体等晚第四纪位移量的研究表明,在黄香沟一带,断裂晚更新世晚期以来的水平位移量最大为40~60m;最小为6~8m,可能是一次滑动事件的特征位错量。断裂带上的位移具有分组特征,各组位移值之间具有6~8m的稳定增量。位移值的分组性和增量特征反映了该段断裂具有特征地震的活动特征,而7组位错值则反映了断裂7次特征活动事件。关于黄香沟一带与断裂相关的微地貌分析,也获得了大致相对应的事件次数。并由此初步推测,晚更新世晚期以来,该断裂带有过多次强烈活动,活动期次明显 相似文献
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大青山山前活动断裂带分段与潜在震源区划分 总被引:1,自引:1,他引:1
潜在震源区的划分主要包括潜在震源区范围的划定以及震级上限的确定,目前遵循地震构造类比和地震活动重复等原则。而活断层的分段特性也是潜在震源区划分时必须考虑的一个重要因素。大青山山前断裂带至今有3种不同的分段方案,文中比较分析了前人对大青山山前断裂带的分段,并在此基础上对大青山及山前盆地的潜在震源区作了新的划分。鄂尔多斯块体周缘被拉张性断陷盆地围绕,这些断裂系地震构造相似,且除呼包盆地外均有历史8级以上地震记录。文中将大青山山前断裂带与鄂尔多斯块体周缘断裂系进行了构造对比,特别是与华山山前断裂进行了断裂活动性定量对比,得出雪海沟到土左旗段的震级上限为8级,断裂两端潜源震级上限均为7.5级 相似文献
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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
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
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THE STRUCTURAL CHARACTERISTICS OF PANGUSI-XINXIANG FAULT IN THE SOUTHERN MARGIN OF TAIHANG MOUNTAINS 下载免费PDF全文
Pangusi-Xinxiang Fault is a great-scale, deep-incising buried active fault in the southern margin of the Taihang Mountains. In order to find out the location, characteristics, structure and activities of Pangusi-Xinxiang Fault, shallow reflection profiles with six lines crossing the buried faults were carried out. In this paper, based on the high-resolution seismic data acquisition technology and high-precision processing technology, we obtained clear images of underground structures. The results show that Pangusi-Xinxiang Fault is a near EW-trending Quaternary active fault and its structural features are different in different segment. The middle part of the fault behaves as a south-dipping normal fault and controls the north boundary of Jiyuan sag; The eastern part of the fault is a north-dipping normal fault and a dividing line of Wuzhi uplift and Xiuwu sag. The shallow seismic profiles reveal that the up-breakpoint of the Pangusi-Xinxiang Fault is at depth of 60~70m, which offsets the lower strata of upper Pleistocene. We infer that the activity time of this fault is in the lower strata of late Pleistocene. In this study, not only the location and characteristics of Pangusi-Xinxiang Fault are determined, but also the reliable geological and seismological evidences for the fault activity estimation are provided. 相似文献