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地质雷达在活动断裂研究中的应用 总被引：1，自引：0，他引：1
对于快速发生沉积和侵蚀的地区,断裂附近的古地震遗迹会很快被掩埋。获取这些地区断裂的位置、上断点的埋深和标志层的断距等方面的数据至关重要。本文利用地质雷达探测技术探测这些被埋藏的古地震遗迹。以北京平原区正断性质的新夏垫断裂和青藏高原东北缘六盘山地区逆冲性质的六盘山东麓断裂为实验区。通过探测发现,对于断裂两侧地表覆盖层主要为粉土或粉质粘土的新夏垫断裂,地质雷达可精确定位断裂通过的位置,指示上断点的埋深,但无法在地质雷达剖面上识别出各套地层。对于在T1基座阶地上通过的六盘山东麓断裂,地质雷达不但可以精确定位断裂的位置,而且可以在地质雷达剖面上识别出各套地层,进而求得断裂两侧基座的断距。 相似文献
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玉树M_S7.1地震地表破裂带及其同震位移分布 总被引：7，自引：2，他引：5
2010年4月14日青海省玉树县发生MS7.1地震,野外地质考察及室内遥感解译表明地震形成反"L"形地表破裂,长约50公里,宏观震中位于郭央烟宋多(33°3′N,96°51′E)。总体上可分为三段,北段与中段间有16km未发现明显地表破裂形迹,中段和南段呈左阶排列,阶区内发育有右阶羽列式破裂。玉树地震最大位移量不小于1.3m,以左行走滑活动为主,兼有挤压逆冲活动。玉树断裂是本次地震的发震断层,断裂南侧羌塘块体和北侧巴颜喀拉块体差异运动导致了玉树地震的发生。地震复发间隔108～185a。破裂南端与1896年强震破裂之间尚有20余公里未发现破裂,其地震危险性还有待进一步研究。 相似文献
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The East Kunlun fault zone is located in the northern margin of the Bayan Har block. The study of earthquake rupture behavior in the fault zone is of importance for understanding the future seismic risk in northwest Sichuan. A number of geological field investigations, typical micro topography DGPS measurements and sample dating show that the earthquake activity of the East Kunlun fault zone extends to the north boundary of Zoige basin, a segment known as the Luocha segment of Tazang fault. In the satellite image, the segment is seen clearly as gray and yellow strips. The earthquake deformation zone mainly features fault scarp, valleys on the slope, offset gullies and terraces, linear distribution of plants, waterfall, fault spring, fault sag pond, and landslide, collapse and talus associated with surface rupturing. These phenomena are distributed intermittently along the re-existing fault and form a ～50km-long inverse L-shaped deformation zone. Fault activities caused left-lateral offset of gullies and terraces, with horizontal displacement concentrated at 5.5m~6m, 18m～23m, 68m～75m, and 200m～220m, respectively. The recent earthquake occurred between 340±30～500±30BP. The macro epicenter is located 5km～7km northwest of Benduo village, with magnitude of MW7.3～7.4, maximum coseismic displacement of 6m, horizontal displacement 5.5m～6m and vertical displacement 0.2m～0.5m, being in a proportion of 5∶1～10∶1. These phenomena show that the Tazang fault is the causative fault of this earthquake. The fault is a Holocene active fault and was dominated recently by left-lateral movement with a small amount of thrust component under compressive shear stress. This characteristic is similar to the movement in other segments of the East Kunlun fault zone. The results of this study support the "continental escape" model. 相似文献
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郯庐断裂带最新活动的断层分布于潍坊至嘉山一带, 而安丘—莒县断裂是郯庐断裂带的重要活动断裂之一。 基于地质考察、 高密度电法探测和钻孔联合剖面, 对安丘—莒县断裂小店—大店段断层活动证据及断层泥分布特征进行研究。 地质考察发现紫红色砂砾岩逆冲到全新世耕植土上方, 两者之间发育断层泥带, 断层泥内含少量角砾岩, 为全新世活动逆断层。 高密度电法探测结果表明断层通过位置电阻率差异明显。 钻孔联合剖面揭露的地层: 全新世耕植土、 全风化砂质泥岩、 强风化砂质泥岩、 碎裂岩、 断层泥带及中风化砂质泥岩。 钻孔K1和K2揭露深灰色断层泥带, 倾向西, 倾角约为74°, 厚度约为13.9 m, 与南侧出露的断层泥带产状相协调。 工作区范围内, 发育多处褶皱、 破碎带和断层泥带, 断层表现为全新世逆断层性质。 相似文献
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云南龙蟠—乔后断裂剑川段古地震初步研究 总被引：1，自引：0，他引：1
通过遥感影像解译和详细的野外考察,发现龙蟠—乔后断裂带剑川段晚第四纪以来长期活动,横跨断裂的水系左旋断错量可分为40m、140m、550m、1040m四个等级。经详细考察后选择后菁拉分盆地开挖探槽。探槽揭示了两次M6.5古地震事件:一次发生在10010±40a B.P.之前;另一次发生在6130±40aB.P.和6320±40aB.P.之间。结合前人研究,分析得出剑川盆地全新世以来发生了3次M6.5的地震,发生时间分别为1751年、6230±130aB.P.和10737±468aB.P.,其重复间隔约为5300a。由于1751年剑川6级地震相对于前两次地震释放的能量偏小,而且其离逝时间较前一次要明显长一些,故本段的地震危险性仍值得关注。 相似文献
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Since 2001, there have occurred in succession the 2001 Kunlun Mountains M S8. 1earthquake,the 2008 Wenchuan M S8. 0 earthquake,the 2010 Yushu M S7. 1 earthquake and the 2012 Lushan M S7. 0 earthquake in the periphery of the Bayan Har block. By comparison of the characteristics of seismic strain release variations before and after the Kunlun Mountains M S8. 1 earthquake in the same time length in the geodynamical related regions,we found that the seismic strain release was obviously enhanced after the earthquake in the Longmenshan area,Batang area,and the NS-trending valleys at the west of the Hot Spring Basin. The Wenchuan earthquake occurred in the first area,and the Yushu earthquake is related to the second area. After the earthquake rupture occurred on the East Kunlun fault zone on the northern boundary of the Bayan Har Block,crustal materials on the south side of the fault zone migrated to the southeast,leading to a concentration of tectonic deformation in the Longmenshan thrust belt, e ventually rupturing on the Longmenshan thrust belt. This earthquake case illustrates that seismicity enhancement zones are possibly prone to long-term destructive earthquakes. After the M S7. 3 earthquake in Yutian,Xinjiang on February 12,2014,earthquake frequency and seismic strain release markedly increased in the junction area between the eastern Qilian Mountain tectonic belt and the Altun Tagh fault zone,where more attention should be paid to the long-term seismic risk. 相似文献
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利用三维可视化卫星遥感影像分析龙蟠-乔后断裂带的几何结构 总被引：1，自引：0，他引：1
本文对龙蟠-乔后断裂,采用1/5万数字高程模型和2.5m分辨率的ALOS遥感影像,在ENVI 4.5平台上将二者融合,获取三维可视化卫星遥感影像。从不同的角度、尺度,对三维影像进行构造地貌解译,获得断裂的展布和活动性质。之后选择部分场点考察验证,发现地质地貌体的断错特征与影像上分析的一致,说明三维影像的构造地貌解译在获得断裂几何展布研究中完全适用。本文应用该方法对龙蟠-乔后断裂的研究表明:龙蟠-乔后断裂由北向南依次经过老母增、龙蟠东、鸿文、雄古、北高寨、龙门邑、桃园、东富乐、岩峰场等;依据断裂几何不连续、走向变化、活动性质变化等,由北向南分为龙蟠段、鸿文段、九河段、剑川盆地段、东富乐段。龙蟠段与鸿文段为左旋左阶斜列;鸿文段与九河段为左旋左阶斜列,九河段走向相较鸿文段和南侧的剑川段逆时针旋转约5°,九河盆地的发育与走向变化相关;九河段与剑川盆地段为左旋右阶斜列,剑川盆地的发育不仅与龙蟠-乔后断裂相关,更可能与丽江-小金河断裂的活动也相关;剑川盆地段与东富乐段为左旋右阶斜列,斜列区为拉分性质的沙溪盆地。综上可知,龙蟠-乔后槽谷的形成与断裂最新几何结构和运动性质仅在部分段落上一致,从这个角度看槽谷的形成不排除古河道等其它因素的影响。 相似文献
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