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从地震活动参数分析石棉—巧家断裂带的现今活动性 总被引:1,自引:0,他引:1
本文利用1970—1981年间沿石棉—巧家断裂带上不同段落平均值 E、平均能量值 b、平均震级(?)以及地震频度 N 值等地震活动参数的空间分布特征,探讨了该断裂带上不同段落的现今活动性,并据此划分出蠕滑、弱粘滑和粘滑等性质的活动断层段。认为沿断裂带分段(?)、(?)、(?)以及 N 值的空间扫描,是一种利用地震学方法定量的研究活断层现今活动性质及其强震孕育部位的可能理想手段。 相似文献
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昌马断裂带断层岩研究及其粘滑,蠕滑特征 总被引:2,自引:0,他引:2
在对断层岩的分布、内部结构、宏观变形及断层泥中石英颗粒形态、表面特征研究分析的基础上,讨论了昌马断裂带粘滑、蠕滑特征。同时指出,昌马断裂带虽以粘滑运动为主,但仍伴有一定量的蠕滑活动。 相似文献
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龙门山构造带区域稳定性探讨 总被引:13,自引:0,他引:13
根据龙门山构造带的地震地质特征、地震活动规律及新构造活动特征,综合分析认为该地区区域稳定性受控于龙门山断裂带。而断裂带又以韧性切变形为主,蠕滑运动为特征,决定该带在相当长的一段时间内,发生强烈地震的可能性不大。 相似文献
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郯庐断裂带潍坊—嘉山段全新世活断层的活动方式与发震模式 总被引:11,自引:1,他引:11
郯庐断裂带潍坊-嘉山段全新世活断层由三个独立的破裂段组成。从各段的断错地貌,松散堆积物特征,断层本身的特点以及断层泥的显微构造标志看,各段具有共同的特点,就是主要粘滑运动为主,并在震后有蠕滑调整运动,各段具有断层闭锁→粘滑发震→震后调整→断层再次闭锁的发震模式,目前莒县-郯城段仍处于震后调整阶段,而安丘段和新沂-泗洪段由已处于断层闭锁的后期阶段,面临粘滑发震的危险。 相似文献
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根据卫星影像解译和野外调查结果,本文重点分析研究楚雄-南华断裂的活动特征、最新活动时代、第四纪盆地的成因以及与1680年楚雄 6?级地震的关系。吕合、南华等多处第四纪断层剖面揭示了断错龙川江Ⅱ、Ⅲ级阶地晚更新世晚期堆积,表明该断裂是一条晚第四纪活动断裂,其最新时代为晚更新世晚期乃至全新世,运动性质以右旋走滑运动为主,水平走滑速率1.6~2.0mm/a。沿断裂发育有楚雄、南华、子午等多个第四纪拉分盆地。历史上,断裂附近曾发生1680年楚雄 6?级地震和多次中强地震,楚雄-南华断裂为这些地震的发震构造。从更大区域范围看,它与东部的曲江断裂、石屏-建水断裂一起,构成一组斜列的右旋走滑为主的活动断裂带。这种运动学特征类似于川滇菱形块体西南边界的红河断裂带,与川滇菱形块体SE向逃逸(运动)有关。 相似文献
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滇东南楔形构造区的区域断裂几何结构突出地表现为半棋盘格式。具有区域应力场分界意义的红河断裂,把其它几条断裂限制在其北部,并与小江断裂带构成第一级的半断块。构造区内,曲江断裂被李浩寨断裂限制在其西侧;后者与异龙湖断裂交汇于建水盆地中;建水断裂把黑泥地断裂限制于其东,并与李浩寨断裂构成建水盆地右阶拉分岩桥区,向南终止于山花。 深部构造、区域形变及断裂活动表明该构造区是一个断块挤压隆起构造区。最后,对楔形构造区的地震活动与挤压隆起断块运动的关系作了简要的分析 相似文献
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Internal structures and high-velocity frictional properties of a bedding-parallel carbonate fault at Xiaojiaqiao outcrop activated by the 2008 Wenchuan earthquake 下载免费PDF全文
Linfeng Hou Shengli Ma Toshihiko Shimamoto Jianye Chen Lu Yao Xiaosong Yang Yuji Okimura 《地震科学(英文版)》2012,25(3):197-217
This paper reports internal structures of a bedding-parallel fault in Permian limestone at Xiaojiaqiao outcrop that was moved by about 0.5 m during the 2008 MW7.9 Wenchuan earthquake. The fault is located about 3 km to the south from the middle part of Yingxiu-Beichuan fault, a major fault in the Longmenshan fault system that was moved during the earthquake. The outcrop is also located at Anxian transfer zone between the northern and central segments of Yingxiu-Beichuan fault where fault system is complex. Thus the fault is an example of subsidiary faults activated by Wenchuan earthquake. The fault has a strike of 243° or N63°E and a dip of 38°NW and is nearly optimally oriented for thrust motion, in contrast to high-angle coseismic faults at most places. Surface outcrop and two shallow drilling studies reveal that the fault zone is several centimeters wide at most and that the coseismic slip zone during Wenchuan earthquake is about 1 mm thick. Fault zone contains foliated cataclasite, fault breccia, black gouge and yellowish gouge. Many clasts of foliated cataclasite and black gouge contained in fault breccia indicate multiple slip events along this fault. But fossils on both sides of fault do not indicate clear age difference and overall displacement along this fault should not be large. We also report results from high-velocity friction experiments conducted on yellowish gouge from the fault zone using a rotary shear low to high-velocity frictional testing apparatus. Dry experiments at normal stresses of 0.4 to 1.8 MPa and at slip rates of 0.08 to 1.35 m/s reveal dramatic slip weakening from the peak friction coefficient of around 0.6 to very low steady-state friction coefficient of 0.1-0.2. Slip weakening parameters of this carbonate fault zone are similar to those of clayey fault gouge from Yingxiu-Beichuan fault at Hongkou outcrop and from Pingxi fault zone. Our experimental result will provide a condition for triggering movement of subsidiary faults or off-fault damage during a large earthquake. 相似文献
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本文对海原断裂的断层泥的各类特征进行了系统的研究,分析了断层泥带内部的小型断裂类型,探讨了断层泥组分的有机地球化学意义。通过对比,确立了石英碎屑表面机械作用成因的电子显微构造特征组合为活断层的判别标志。本文将石英碎屑表面电子显微溶蚀构造分为五类,据此分析了断层活动时期和状态。研究中还发现了断层泥带内部电子显微结构类型,进而分析了断层活动与微结构、粒度分布间的关系。最后还讨论了断层泥形成演化过程以及断层泥对全新世以来断层滑动性能影响及其与地震活动的关系 相似文献
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Internal structures and high-velocity frictional properties of Longmenshan fault zone at Shenxigou activated during the 2008 Wenchuan earthquake 下载免费PDF全文
Yu Wang Shengli Ma Toshihiko Shimamoto Lu Yao Jianye Chen Xiaosong Yang Honglin He Jiaxiang Dang Linfeng Hou Tetsuhiro Togo 《地震科学(英文版)》2014,27(5):499-528
This paper reports internal structures of a wide fault zone at Shenxigou, Dujiangyan, Sichuan province, China, and high-velocity frictional properties of the fault gouge collected near the coseismic slip zone during the 2008 Wenchuan earthquake. Vertical offset and horizontal displacement at the trench site were 2.8 m (NW side up) and 4.8 m (right-lateral), respectively. The fault zone formed in Triassic sandstone, siltstone, and shale about 500 m away from the Yingxiu-Beichuan fault, a major fault in the Longmenshan fault system. A trench survey across the coseismic fault, and observations of outcrops and drill cores down to a depth of 57 m revealed that the fault zone consists of fault gouge and fault breccia of about 0.5 and 250–300 m in widths, respectively, and that the fault strikes N62°E and dips 68° to NW. Quaternary conglomerates were recovered beneath the fault in the drilling, so that the fault moved at least 55 m along the coseismic slip zone, experiencing about 18 events of similar sizes. The fault core is composed of grayish gouge (GG) and blackish gouge (BG) with very complex slip-zone structures. BG contains low-crystalline graphite of about 30 %. High-velocity friction experiments were conducted at normal stresses of 0.6–2.1 MPa and slip rates of 0.1–2.1 m/s. Both GG and BG exhibit dramatic slip weakening at constant high slip rates that can be described as an exponential decay from peak friction coefficient μ p to steady-state friction coefficient μ ss over a slip-weakening distance D c. Deformation of GG and BG is characterized by overlapped slip-zone structures and development of sharp slickenside surfaces, respectively. Comparison of our data with those reported for other outcrops indicates that the high-velocity frictional properties of the Longmenshan fault zones are quite uniform and the high-velocity weakening must have promoted dynamic rupture propagation during the Wenchuan earthquake. 相似文献
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断层泥的再生显微结构特征及其地震地质意义 总被引:3,自引:1,他引:3
三轴剪切摩擦实验后的断层泥与天然断层泥的再生显微结构特征研究表明,断层泥的显微结构特征与断层滑动方式之间有一定的关系,稳滑使断层泥变形均匀,产生低角度剪切(<14°)、布丁构造和颗粒碎裂流动。粘滑使断层泥局部发生强烈变形、高角度剪切(>14°)和碎粒出现随机裂纹等。断层泥的再生显微结构特征可用作鉴别古地震的存在 相似文献
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蒙脱石的脱水作用对断层摩擦本构行为的影响 总被引:4,自引:3,他引:4
利用高温双轴摩擦装置,研究了含蒙脱石的断层带在不同温度下摩擦滑动的速度依赖性,以期了解脱水作用对摩擦行为的影响。结果表明,断层带摩擦强度随温度而升高,而速度依赖性较为复杂,以1.4u/s为界,室温和100℃时,低滑动速率下表现为微弱的速度弱化,高滑动速率下则表现为速度强化;200℃时均为速度强化;300℃时高滑动速率下仍为速度强化,但低滑动速率下转变为速度弱化;400℃以上,均为明显的速度弱化。摩擦行为的变化与脱水过程及相应的断层物质变形方式的变化密切相关 相似文献