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云南地区数字地震波波速比的区域特征 总被引：2，自引：0，他引：2
从1998～2006年间云南地区数字地震台网记录中,选用有4个以上台记录到的震相清晰的直达Pg波、Sg波的到时(包含Pg、Sg的到时差在20～25 s的远台和小于0.5 s的近台),计算出云南地区数字地震波的波速比(VP/VS),并分析了其区域分布特征.结果表明:1998～2006年云南地区波速比月均值为1.685,滇西南地区的月均值高于云南地区的月均值;滇西地区的月均值变化幅度相对较小, 2002年10月至2004年11月间的月均值低于云南地区的月均值.2005年云南地区的波速比整体偏高,平均值达1.74,高于多年均值,可能是2004年印尼8级大震后云南地区波速比的一种新变化. 相似文献
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分析研究了南黄海和东海地区18口石油勘探钻井的井孔崩落特征，结合对琉球岛弧和冲绳海槽地区浅源地震震源机制解的分析，确认了南黄海地区与我国华北地区有类似的现代构造应力场特征；并得出东海地区的最大水平压应力方向为NEE-SWW，最小水平压应力方向为NNW-SSE，它们分别与冲绳海槽地区的最大和最小主压应力方向接近;东海地区地壳上层的水平差应力可能不强，这与该地区没什么地震活动的特点是一致的．根据应力场特征推断，我国东部地区并未受到菲律宾海板块俯冲的推挤作用，而是可能受到垂直于冲绳海槽走向的拉伸作用的影响． 相似文献
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对于陆域地区，我国已进行5次全国范围大面积地震区划研究工作，获得了丰富研究成果。但对于海域地区地震区划的研究较薄弱，较少涉及海域潜源划分模型。随着经济发展，涉及海域地区的经济活动日益频繁，对海域地区潜源划分研究及进一步地震区划研究工作的需求越来越强烈。为此，详细介绍代表性国家在潜源划分方面采取的原则和方法，总结我国海域地区地震地质背景及相应的研究现状，并在此基础上提出我国海域地区潜源划分可考虑的原则和基本思路，为后续我国海域地区区划研究提供方案。 相似文献
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采用2014年10月22日至2019年4月11日之间的26景Sentinel-1升轨数据，基于PS-InSAR技术对蓟运河断裂这一隐伏断裂进行形变监测试验。结果表明：(1)研究区受地面沉降干扰强烈地区在南部宁河一带，向北地面沉降逐步减弱，在蓟运河断裂北段以北一带基本无地面沉降现象。(2)研究区北部的视向线形变速率在蓟运河断裂北段一带在0 mm·a-1左右，向北随远离断裂形变速率增大，表明研究区北部受近东西向燕山隆起控制，有向南掀斜运动的趋势。(3)蓟运河断裂北段活动方式为黏滑，其两盘的视线向相对形变速率差约为1.83 mm·a-1,蓟运河断裂南段两盘形变速率差小于2.96 mm·a,与2005—2012年的水准测量结果相近，表明蓟运河断裂2005年以来活动速率较为稳定。(4)在受到地面沉降影响下，隐伏断裂的InSAR形变场包含更多的非构造信息，无法获取断裂的具体形变速率。但断裂活动会导致断裂两盘含水层厚度不同，地下水超采造成的地面沉降幅度也不同，相应的其InSAR形变场在断裂两盘出现突变，对隐伏断裂的位置判定有一定意义。 相似文献
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Ordos block was squeezed by the Qinghai-Tibetan block and North China block, and the tectonic activity was intense. In the periphery of Ordos block, there was a series of folds zones and compressed faults with complicate structures. This paper used three-phase data of 1980,1990 and 2014 to calculate vertical velocity of Northwestern margin of Ordos and the analytical results indicated that ① the Hetao basin between the rise of Yinshan fault block and Ordos fault block showed relatively subsidence, in which Linhe basin was the most evident and the subsidence rate was about 2-4mm/a. The subsidence rate of Jartai -Yinchuan rift zone on the western margin of Ordos block was about 2mm/a; ② the whole testing zone exhibited the evident inherited movement characterized by mountain rise and basin subsidence; ③the two leveling section through the northern margin fault and Dengkou-Benjing fault showed that the difference between vertical velocities on two sides of the fault was less than 0.5mm/a. 相似文献
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Precise leveling data observed in the period of 1970–2014 around the Ordos block were collected and processed to estimate present-day crustal vertical movement. Vertical rates of 6 GPS sites were employed as a priori constraints to define the reference frame. The velocity field shows that the interior of the Ordos block moves upward at a rate of 3 mm/a as a stable block. With respect to the central Ordos, the grabens and rifts around the Ordos block are undergoing subsidence, while the northeastern and southwestern Ordos uplift at the average rates of 2 and 1 mm/a, respectively. To the southeastern margin of the Ordos block, the Weihe and southern Shanxi grabens are subsiding at the rates of 4–6 mm/a. The subsidence of the Shanxi graben indicates that the graben is experiencing extensional movement on a long timescale. To the northwestern margin of the Ordos block, the Hetao and Yinchuan rifts are subsiding at the rates of 2–3 mm/a. A 2-D buried faulting model is used to infer the normal or reverse dip-slip rates. Our solution shows that most of the normal slip rates along the faults in the grabens and rifts are ~2 mm/a. 相似文献
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Analysis of fault outcrops and trench sections indicates fault displacements of 0.2m - 6.0 m on the bottom paleosol layer of the Epipleistocene with the maximum rate of 0.047 mm/a and an average displacement of 1.1 meters. The activity appears as fissures on the fault surface in the late Epipleistocene and there is no obvious displacement. The fault activity is weak and the most active segment is the Bailuyuan segment. 相似文献
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由滨海相沉积样品反映的东南沿海海岸升降速率 总被引：1，自引：0，他引：1
收集了闽、粤、桂、琼4省（区）海岸带的^14C测年自45000aB.P.以来共490个演海相样品，依据文献[1]广东中山石歧45000aB.P，以来的渐进上升水动型海平面变化曲线，计算了相应地区晚更新世及全新世以来海岸地壳的升降速率，结果表明，除粤西和粤东一些地区及海南省外，东南沿海海岸部份地壳的升降速率，结果且明，除粤西和粤东一些地区及海南省外，东南沿海海岸份地区晚更新世及全新世时期和中期地壳主要表现为下沉，全新世中晚期特别是晚期主要反映为上升，珠江三角洲晚更新世中晚期以来主要表现为继承性下沉，现代地壳形孪测量反映的地壳升降较多地区与一述趋向大致相似，广东惠来县东60km下新礁海域及珠江三角洲灯笼沙等15个地区，是地壳升降异常速率较高地区。 相似文献
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A Preliminary Study on the New Activity Features of the Lajishan Mountain Fault Zone in Qinghai Province 总被引：3，自引：0，他引：3
Yuan Daoyang 《中国地震研究》2005,19(4):391-401
INTRODUCTIONThe Lajishan Mountainlies onthe northeastern margin of Qinghai_Xizang(Tibet)plateau.It is ageomorphic gradient zone,separatingthe hinterland of Tibetfromthe Loess plateau.The Lajishanfaultis a product of Caledonian movement,havingexperienced m… 相似文献
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华北山地地貌面与新生代构造运动 总被引：6，自引：2，他引：6
华北山地有三期山地夷平面，四期河流阶地面。表明新生代地壳运动具有垂直差异性质。以上升运动为主，平均升幅１７００ｍ，速度０．０３１ｍｍ／ａ。以第四纪为最大。全区新地壳构造形迹可划分为３大类，８亚类和３２个小类。在新生代构造运动中，又划分出第四纪以来的新构造运动和晚更新世以来的最新构造运动。 相似文献
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Crustal movement and deformation in Taiwan and its coastal area 总被引：1，自引：0，他引：1
Introduction Both Taiwan Island and Chinese mainland belong to Eurasian plate in geological structure. And the nearest distance between Taiwan Island and Fujian Province, which is located on the opposite coast, is only 130 km. Although there are high-precision GPS networks in both Taiwan and Fujian Province, joint GPS measurement cannot be made directly because of the inconvenient contact due to the strait between them. However, the GPS networks arranged on b… 相似文献
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研究表明 ,深沪湾地区晚更新世早中期地壳运动以下沉为主 ,沉积了冲洪积含砾砂粘土层。晚更新世中晚期以来地壳先升后降 ,近 15 0 0aB .P .以来地壳较为稳定。在 (2 5 5 80± 2 4 90 )～15 4 6 0aB .P .期间 ,该区地壳与水动型海平面大致同步升高 ,上升幅度为 8m左右 ,速率达 0 .78mm/a ,深沪湾内生长了古牡蛎。 15 4 6 0～ 110 0 0aB .P .期间 ,该区地壳快速上升 ,上升幅度超过 10m ,速率超过 2mm/a ,形成多个由晚更新世含砾砂粘土构成的低凹洼地 ,古牡蛎滩成为台地。其后地壳稳定 ,在低凹洼地内生长了古森林。 70 0 0aB .P .深沪湾发生了由强古地震导致的地壳快速下沉 ,古森林生长的凹陷洼地变成泻湖环境 ,古牡蛎滩台地与海面很接近。 2 0 0 0aB .P .左右 ,深沪湾又一次发生由强古地震导致的地壳快速下沉 ,古森林下沉到更深的海底 ,古牡蛎滩回到潮间带海域 相似文献
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Based on the GPS velocity field data of 1999-2007 and 2011-2013,we used the least squares configuration method and GPS velocity profile results to synthetically analyze the dynamic evolution characteristics of crustal deformation in the Yunnan area before and after the Wenchuan earthquake. The dynamic evolution of GPS velocity field shows that the direction is gradually changed from the south in the southern part of the Sichuan-Yunnan block to the south-west in the southern Yunnan block and there is a clear relative motion characteristic near the block boundary fault zone. Compared with the GPS velocity of 1999-2007, the results of 2011-2013 also reflect segmental deformation characteristics of the block boundary fault zone. Southeast movement shows a significant increase, which may be related to crustal deformation adjustment after the Wenchuan earthquake. The dynamic evolution of strain parameters shows a pattern of "extension in the middle and compression at both ends" in the whole area and the distribution of deformation (shear, extension or compression) is closely related to the background motion and deformation characteristics of the main fault zone. Compared with the results of the period of 1999-2007, the extensional deformation zone of 2011-2013 is expanded eastward and southward. The compressional deformation of the eastern boundary (the Xiaojiang fault zone) of the Sichuan-Yunnan block is no longer significant, which is mainly concentrated in the northern section of the Xiaojiang fault zone and may be related to the post-seismic deformation adjustment of the Wenchuan earthquake. The GPS velocity profile results show that the left-lateral slip velocity of the Xiaojiang fault zone reduced gradually from north to south (10mm/a-5mm/a), and the width of the northern section is wider. The right-lateral slip rate of the Honghe fault zone is about 4mm/a, and the deformation width is wider. The dynamic results show that the Wenchuan earthquake has little effect on the deformation modes of these two fault zones. 相似文献