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1.
为克服InSAR观测汶川地震同震形变场的邻轨不连续问题,提出联合GPS观测值与邻轨平滑约束的同震位移校正方法,采用GPS观测形变去除PALSAR轨道误差引入的残留平地相位,基于形变平滑条件校正邻轨干涉相位的不连续性.ALOS/PALSAR干涉处理结果表明,校正后同震形变场的准确度与平滑性得以显著提高,InSAR高相干点残差达3.6 cm,校正后精度提高约60%,低相干点精度提高约40%,校正后形变场的邻接平滑因子标准差减小约33%,验证了轨道误差校正与邻轨平滑约束方法的准确性与可靠性.进一步基于弹性半空间位错模型的断层滑移反演结果表明,断层滑移主要分布于映秀、北川和青川地区,集中于地壳深度0~16 km范围,最大滑动量（位于北川县城）约为9.0 m,GPS反演模型残差为5.5 cm,InSAR反演模型残差达9.2 cm,InSAR反演精度约有30%的显著提高,由模型反演计算得到的地震矩为8.0469×1020 N·m. 相似文献
2.
David Ching-Fang Shih Yih-Min Wu Gwo-Fong Lin Jyr-Ching Hu Yue-Gau Chen Chien-Hsin Chang 《Stochastic Environmental Research and Risk Assessment (SERRA)》2008,22(3):401-410
A transition and subduction zone adjacent to the Ryukyu Arc, Ryukyu Trench, and Okinawa Trough, extends between southern Japan
and northeastern Taiwan. It is generated during the northwestward subduction of the Philippine Sea Plate, which lies the Eurasian
Plate along the Ryukyu Trench. The movement of the Philippine Sea Plate is hindered at the northeastern corner of Taiwan,
which causes complicated structure of the Philippine Sea Plate at the western end of the Ryukyu subduction zone. Development
of the active subduction and transition boundary near the western Ryukyu Arc is evaluated statistically by using displacements
derived from GPS site data. The statistical model shows that the absolute displacement derived from GPS measurements of nearly
8 years indicates a maximum spatial variation of 0.625 m. Three trends are observed for such long-term progress, and use of
linear regression also reveals quite good consistency between the data and statistic models. Such rate is also elevated following
the trend development. Southeastern and nearly horizontal movement is suggested to the main development of for the site movements,
it is likely related to the tensional activity adjacent to this boundary. 相似文献
3.
Chung Huang Yu-Chang Chan Jyr-Ching Hu Jacques Angelier Jian-Cheng Lee 《Journal of Structural Geology》2008,30(9):1167-1176
The northern segment of the Chelungpu Fault shows an unusually large co-seismic displacement from the event of the Mw 7.6 Chi-Chi earthquake in western Taiwan. Part of the northern segment near the Fengyuan City provides an excellent opportunity for characterizing active thrust-related structures due to a dense geodetic-benchmark network. We reproduced co-seismic deformation patterns of a small segment of this Chelungpu Fault using 924 geodetic benchmarks. According to the estimated displacement vectors, we identified secondary deformations, such as local rigid-block rotation and significant shortening within the hanging wall. The data set also allows us to determine accurately a 3D model of the thrust fault geometry in the shallow subsurface by assuming simple relations between the fault slip, and the horizontal and vertical displacements at the surface. The predicted thrust geometry is in good agreement with borehole data derived from two drilling sites close to the study area. The successful prediction supports our assumptions of rigid displacement and control of displacement in the hanging wall by the fault geometry being useful first approximations. 相似文献
4.
Jian-Cheng Lee Jacques Angelier Hao-Tsu Chu Jyr-Ching Hu Fu-Shu Jeng 《Comptes Rendus Geoscience》2005,337(13):1200-1207
In 1998 we installed five creepmeters across the Chihshang Fault, the active plate suture in eastern Taiwan. Daily creepmeter data indicated decreasing creeping rate from 1999 to 2003, suggesting increasing seismic hazard. The fault was ruptured by the Chengkung earthquake () on 10 December 2003. Through extrapolation of our earlier creep data of 1986–1991 and 1992–1997, we evaluate the minimum deficit in aseismic creep shortening as 106 or 46 mm (respectively) before this earthquake. The near-surface co-seismic shortening was limited, but the total shortening resulting from the earthquake, including post-seismic creep, was about 97 mm. This suggests that near the surface most of the detectable deficit has been absorbed by this earthquake and subsequent creep. We thus point out that creepmeter installation and monitoring bring a powerful tool in seismic hazard mitigation. To cite this article: J.-C. Lee et al., C. R. Geoscience 337 (2005). 相似文献
5.
6.
Using differential SAR interferometry to map land subsidence: a case study in the Pingtung Plain of SW Taiwan 总被引：3，自引：2，他引：1
Hsieh Chia-Sheng Shih Tian-Yuan Hu Jyr-Ching Tung Hsin Huang Mong-Han Angelier Jacques 《Natural Hazards》2011,58(3):1311-1332
Synthetic aperture radar (SAR) interferometry (InSAR) is a geodetic tool widely applied in the studies of earth-surface deformation.
This technique has the benefits of high spatial resolution and centimetre-scale accuracy. Differential SAR interferometry
(DInSAR) is used to measure ground deformation with repeat-pass SAR images. This study applied DInSAR and persistent scatterers
InSAR (PSInSAR) for detecting land subsidence in the Pingtung Plain, southern Taiwan, between 1995 and 2000. In recent years,
serious land subsidence occurred along coastal regions of Taiwan as a consequence of over-pumping of underground water. Results
of this study revealed that the critical subsidence region is located on the coast near the estuary of Linpien River. It is
also found that subsidence was significantly higher during the dry season than the wet season. The maximum annual subsidence
rate of the dry season is up to −11.51 cm/year in critical subsidence region and the vertical land movement rate is much slower
during the wet season. The average subsidence rates in wet and dry seasons are −0.31 and −3.37 cm/year, respectively. As a
result, the subsidence rate in dry seasons is about 3 cm larger than in wet seasons. 相似文献
7.
The mechanism of the 1941 Tsaoling landslide, Taiwan: insight from a 2D discrete element simulation 总被引：1，自引：0，他引：1
Chao-Lung Tang Jyr-Ching Hu Ming-Lang Lin Ren-Mao Yuan Ching-Chuan Cheng 《Environmental Earth Sciences》2013,70(3):1005-1019
Tsaoling is located in Southwestern Taiwan, 10 km east of the frontal thrusts of the mountain belt. Five large historical landslide events were recorded from 1862 to 1999. No details of the earliest landslide event (1862) are available, thus this paper deals with the 1941 landslide event. Using the Particle Flow Code in two dimensions (PFC 2D) to simulate the mechanism of the Tsaoling landslide in 1941, this study shows that the landslide block developed cracks and slid down 0.2–1.8 m on the sliding plane. The cracks concentrated in certain zones, which corresponded to future landslide detachment planes. During the vibration simulation, the cracks spread from the shear plane to ground surface. Monitoring the variations of the displacements, velocity, and stress during vibration simulation showed that the peak velocity and stress in the transition zones occurred at 3 s. The displacement of the left part of the block exceeded 1.3 m, and the displacement of the right part was less than 1.3 m during vibration simulation. These results suggest that the left part of the block was pushed down by the right part, ultimately inducing a landslide during an earthquake. 相似文献
8.
联合高精度的GPS水平位移观测和高密度的PS-InSAR雷达视线位移测量,实现地表三维形变的精确反演.本文在准确计算卫星轨道方位角基础上,使用GPS观测位移与星载雷达LOS方向形变的投影转换模型,将雷达LOS方向形变转换为垂直方向位移,并基于地面GPS与SAR影像PS目标联合构建形变监测网,采用参数平差算法估计区域地表形变场.以地质构造活动极其活跃的台湾岛及其西南屏东高雄地区为例,联合屏东地区48个GPS监测台站与雷达PS目标,监测该地区从1995-1999年间由于板块构造挤压运动和地下水抽取导致的三维地表形变.结果表明,该地区年均水平位移量为向西30~50 mm/a,高雄沿海地区发生明显的逆时针西偏南的逐渐增大的水平位移;垂直位移为屏东平原南部呈现-10 mm/a~-15 mm/a的地面沉降,而平原北部和高雄地区呈现约+5 mm/a~+10 mm/a的地面抬升. 相似文献
9.
针对汶川地震PALSAR观测的方位向形变场存在严重电离层影响,导致准确提取断层地表破裂线困难的问题,本文使用一种基于频率域的电离层影响校正方法,从方位向形变场频域数据中提取电离层信号对应的频域信息,通过建模获得空间域电离层信号,并与原始形变场进行差分运算完成电离层影响的校正,还原了汶川地震断层近场沿SAR方位向的真实地表形变场.以校正后的方位向形变场作为数据源,采用非极大值抑制二维梯度算法,准确提取汶川地震北川—映秀断层和灌县—江油断层的地表破裂线.为验证提取结果的可靠性,引入野外地质调查数据进行对比分析,定量计算两条破裂线间的距离差异,结果表明基于SAR形变场自动提取的断层破裂线与野外地质调查数据具有较高的一致性,利用SAR观测形变场可作为调查地震断层地表破裂的重要补充手段. 相似文献
10.
通过综合分析2008年5月12日汶川地震野外地震地质考察的地表破裂带空间分布及分段资料,结合InSAR干涉形变场资料,构建了五段断层几何结构模型,该模型与野外地震地质考察结果在多数分段上基本一致;基于此五段断层模型,运用敏感性迭代拟合算法反演了汶川地震InSAR同震形变场,获得了断层滑动分布及部分震源参数.结果表明,基于余震精定位获得的地震断层倾角模型模拟的同震形变场与InSAR形变场吻合较好,且残差较小;反演的滑动分布主要集中于地下0～20 km,最大滑动量分别位于北川及青川等地区,最大可达到10 m;沿SW-NE走向,断层面的滑动方向主要以右旋兼逆冲形式为主,在汶川及都江堰地区以强烈的逆冲为主兼有一定右旋走滑分量,在北川及映秀地区以逆冲兼右旋运动为主,在平武及青川等地区则逐渐过渡为以右旋运动为主兼有一定的逆冲分量,其中汶川地区的平均滑动角为97°,北川地区的平均滑动角为119°,青川地区平均滑动角为138°.反演矩张量为7.7×1020 N·m,矩震级达Mw7.9. 相似文献