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岩石摩擦滑动失稳前断层区的波速变化 总被引：2，自引：0，他引：2
对岩石摩擦滑动失稳前断层区的波速变化进行了实验研究，实验表明，岩石摩擦滑动失稳前沿断层一侧的测线上观测不到测速变化，沿着跨断层的测线可观测到波速下降的前兆，因此，尝试用波速异常预断层带粘膜型地震时，选择测线应跨断层。 相似文献
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合肥台跨断层短水准测量场地位于郯庐断裂带南段．1987年后测量资料长期趋势变化主要是西端点（A点）场地受荷载变迁等环境条件改变的干扰造成的。2007年新建支线10—S段,经改造形成跨断层测线B—S段,2008-01-01～2008—12-31试测,试测结果表明：10一S段观测精度优于原线路的10—A段;跨断层B—S段观测资料2008年9月以前变化平稳．9月以后的趋势性变化可能是肥东邶．5级地震的震前反映。由此认为：跨断层短水准测量测线布设既要有利于断层形变信息提取,又要能有效地分析排除干扰。并要进行多组的观测。增加检核条件。 相似文献
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利用呼图壁地震台洞体场地水准二期的比对观测数据、呼图壁场地跨断层水准四期的同时间段观测资料以及1987~2012年大丰跨断层测线的水准观测数据,分析了呼图壁红山地震台洞体场地水准观测成果的变化速率与跨断层水准观测成果的年变速率的差异性,判定原地震台使用的Ni004光学水准仪的可靠性,依据分析结果提出合理建议。并根据大丰跨断层水准观测的历史观测成果和呼图壁洞体场地水准观测比对后的分析结果,初步探索研究跨断层水准在研究区域的地形变特征。 相似文献
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《地震地磁观测与研究》2016,(4)
通过实地观测和对南通地震台跨断层水准N—S_1测线观测资料进行梳理,发现测站之间、测线观测值与气象因素之间存在必然联系,表现为:N—S_1测线高差变化规律总体呈年周期性质,2009年8月以来观测值具有整体变小趋势,反映了近期N—S_1测线断层活动特征。 相似文献
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断层运动方式与滑动速率是断层活动性研究和地震危险性判定的重要参数。本文基于山西断陷带多年积累的跨断层水准观测资料,在处理与重构的基础上采用断层活动性分析方法,基于构造分区给出各构造区主要断层现今运动特征。结果表明,山西断陷带主要断层在观测期内以继承性正断运动为主,各盆地断层运动特征具有显著差异,表现为南、北两段的垂直活动量明显大于中段,其中,忻定盆地累积变化量值最小。从断层垂直活动速率来看,五台山断裂、系舟山山前断裂、唐河断裂和霍山山前断裂跨断层测段活动速率明显低于全区水平;受长期构造应力加载及区域中强地震影响,各时段断层运动也存在差异变化,下达枝、亭旨头、太原、广胜寺等部分跨断层测段表现出明显的断层逆继承运动、断层相对闭锁等特征。 相似文献
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利用小波变换分析方法提取沂沭断裂带及其分支断裂跨断层流动短水准和长水准趋势变化成分, 计算分析不同断裂的垂直形变速率和受力状态, 结果表明: 沂沭断裂带及其北西向分支断裂近期垂直形变速率均较小, 没有明显的速率异常和受力状态改变; 同一断裂具有分段和分时活动特征, 断裂活动性质与地质考察结果基本一致; 大部分水准观测场地在1995年苍山5.2级、 2011年日本9.0级地震前后断裂垂直形变速率和受力方式发生了变化; 山东近几年出现的跨断层水准异常基本结束, 仅存的冯家坊子水准异常存在一定干扰, 沂沭断裂带及附近地区近期发生强震的形变背景尚不明显。 相似文献
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以首都圈地区布设在不同断层上的24处跨断层水准观测为研究对象, 建立了地壳分层结构、 含不同倾角断层的三维有限元模型, 模拟计算了断层倾角和走向对跨断层水准观测结果的影响, 并结合跨断层水准测量资料、 震例研究及R值预测评分, 对首都圈地区跨断层水准测量监测能力进行了初步评价。 结果表明: ① 跨断层水准观测能力一定程度上受倾角和走向因素的共同影响; ② 跨断层水准布设于倾角30°~70°且走向与地面水平最大位移方向近垂直时具有较好的映震效能; ③ 首都圈跨断层水准监测体系总体而言具备较强的监测能力。 相似文献
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对金州短水准观测和资料分析中常易引起争议或新出现的若干重要问题进行论论，其结果对跨断层形变测量具有普遍意义。 相似文献
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本文利用虾拉沱跨断层测量资料,通过必要的数学处理,分析了鲜水河断裂带在该处的总体活动趋势和年周期变化,研究了断层活动在主破裂带及其两侧的分布情况,提出了一个该处断层活动模型 相似文献
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北京黄庄—高丽营断层,八宝山断层中段活动性综合研究 总被引：7，自引：0，他引：7
在黄庄－高丽营断层及八宝山断层中段布设了监测断层活动性的水淮、短边测距、重力、地磁等的共点同步观测网，分析了各观测量的时空分布及相互关系。研究认为，黄庄－高丽营断层处于应变能积累的闭锁状态；八宝山断层处于蠕动或旷动的状态；应用形变及重磁手段共点同步综合监测断层活动性，可以获得断层活动的微动态的丰富信息。 相似文献
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—The interpretation of the results of regional and local leveling which began in 1977 in the Mexicali Valley and the local short profile precision leveling which started in 1994 are discussed. The relation of vertical deformations around the Cerro Prieto Geothermal Field (CPGF) and along the Imperial fault, with local tectonics and seismicity in the Mexicali Valley, is reviewed. Also the relation between vertical deformation and fluid operation in the CPGF is analyzed. The subsidence observed in the field seems to be induced by fluid extraction. The way in which fluid production influences surface changes along the Imperial fault is not clear. The possibility that seismicity is triggering subsidence in the area and vertical movement on the Imperial fault is discussed. 相似文献
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Based on GPS velocity during 1999-2007, GPS baseline time series on large scale during 1999-2008 and cross-fault leveling data during 1985-2008, the paper makes some analysis and discussion to study and summarize the movement, tectonic deformation and strain accumulation evolution characteristics of the Longmenshan fault and the surrounding area before the MS8.0 Wenchuan earthquake, as well as the possible physical mechanism late in the seismic cycle of the Wenchuan earthquake. Multiple results indicate that:GPS velocity profiles show that obvious continuous deformation across the eastern Qinghai-Tibetan Plateau before the earthquake was distributed across a zone at least 500km wide, while there was little deformation in Sichuan Basin and Longmenshan fault zone, which means that the eastern Qinghai-Tibetan Plateau provides energy accumulation for locked Longmenshan fault zone continuously. GPS strain rates show that the east-west compression deformation was larger in the northwest of the mid-northern segment of the Longmenshan fault zone, and deformation amplitude decreased gradually from far field to near fault zone, and there was little deformation in fault zone. The east-west compression deformation was significant surrounding the southwestern segment of the Longmenshan fault zone, and strain accumulation rate was larger than that of mid-northern segment. Fault locking indicates nearly whole Longmenshan fault was locked before the earthquake except the source of the earthquake which was weakly locked, and a 20km width patch in southwestern segment between 12km to 22.5km depth was in creeping state. GPS baseline time series in northeast direction on large scale became compressive generally from 2005 in the North-South Seismic Belt, which reflects that relative compression deformation enhances. The cross-fault leveling data show that annual vertical change rate and deformation trend accumulation rate in the Longmenshan fault zone were little, which indicates that vertical activity near the fault was very weak and the fault was tightly locked. According to analyses of GPS and cross-fault leveling data before the Wenchuan earthquake, we consider that the Longmenshan fault is tightly locked from the surface to the deep, and the horizontal and vertical deformation are weak surrounding the fault in relatively small-scale crustal deformation. The process of weak deformation may be slow, and weak deformation area may be larger when large earthquake is coming. Continuous and slow compression deformation across eastern Qinghai-Tibetan Plateau before the earthquake provides dynamic support for strain accumulation in the Longmenshan fault zone in relative large-scale crustal deformation. 相似文献