Based on the analysis of coseismic deformation in the macroscopic epicentral region extracted by Differential Interferometric Synthetic Aperture Radar (D-InSAR), and combined with the seismic activity, focal mechanism...Based on the analysis of coseismic deformation in the macroscopic epicentral region extracted by Differential Interferometric Synthetic Aperture Radar (D-InSAR), and combined with the seismic activity, focal mechanism solutions of the earthquake and field investigation, the characteristic of coseismic deformation of MS=8.1 western Kunlunshan Pass earthquake in 2001 was researched. The study shows that its epicenter lies in the northeast side of Hoh Sai Hu; and the seismogenic fault in the macroscopic epicentral region can be divided into two central deformation fields: the west and east segments with the lengths of 42 km and 48 km, respectively. The whole fault extends about 90 km. From the distribution of interferometry fringes, the characteristic of sinistral strike slip of seismogenic fault can be identified clearly. The deformations on both sides of the fault are different with an obviously higher value on the south side. In the vicinity of macroscopic epicenter, the maximum displacement in look direction is about 288.4 cm and the minimum is 224.0 cm; the maximum sinistral horizontal dislocation of seismogenic fault near the macroscopic epicenter is 738.1 cm and the minimum is 551.8 cm.展开更多
Deterministic, probabilistic and composite-grading methods are used to get the possible locations of strong earth-quakes in the future in Norwest Beijing and its vicinity based on the quantitative data and their accur...Deterministic, probabilistic and composite-grading methods are used to get the possible locations of strong earth-quakes in the future in Norwest Beijing and its vicinity based on the quantitative data and their accuracy about active tectonics in the research area and by ordering, some questions in the results are also discussed. It shows that the most dangerous fault segments for strong earthquakes in the future include: segments B and A of the southern boundary fault of the Yangyuan basin, the southern boundary fault of the Xuanhua basin, the east segment of the southern Huaian fault and the east segment of the northern YanggaoTianzhen fault. The most dangerous area is YangyuanShenjing basin, the second one is TianzhenHuaianXuanhua basin and the third dangerous areas are WanquanZhangjiakou and northeast of Yuxian to southwest of Fanshan.展开更多
利用1989—1996年滇西地震预报实验场绝对重力和相对重力观测资料,采用逐年差分和多年累积的方法,分析滇西地震预报实验场内部不同时间尺度的重力场演变特征及其与丽江地震在时空上的对应关系,结果表明:①1992年以前,研究区内部重力场...利用1989—1996年滇西地震预报实验场绝对重力和相对重力观测资料,采用逐年差分和多年累积的方法,分析滇西地震预报实验场内部不同时间尺度的重力场演变特征及其与丽江地震在时空上的对应关系,结果表明:①1992年以前,研究区内部重力场变化平稳,1993年出现局部变化,1995年变化急剧加大,震后快速反向调整,变化量值基本与震前多年累积相当,重力场演化特征与丽江地震存在高度时空对应关系,表明该时段重力场变化为丽江地震的孕震特征。②研究区差分及累积重力场动态演化过程中,在川滇菱形块体与滇西块体边界产生重力变化梯度带,表明这2个块体构造活动剧烈。③沿红河断裂带出现(-60~90)×10-8 m/s 2的重力变化高梯度带,其走向与红河断裂构造高度一致,反映区域重力场变化受主要活动构造控制,是地下深部壳幔物质运移的表现。展开更多
针对相对重力观测过程中可能受到环境等因素影响而出现高频信号和局部异常的情况,以2021年漾濞6.4级地震前重力变化为例,通过时空平滑约束重构重力变化数据,对比重构前后重力变化情况。基于球坐标系下六面体模型模拟场源体介质,反演场...针对相对重力观测过程中可能受到环境等因素影响而出现高频信号和局部异常的情况,以2021年漾濞6.4级地震前重力变化为例,通过时空平滑约束重构重力变化数据,对比重构前后重力变化情况。基于球坐标系下六面体模型模拟场源体介质,反演场源视密度变化,分析场源区介质密度演化特征。结果显示:观测数据经过时空平滑重构后,在不改变总体变化趋势的情况下,标准差由17.86×10-8 m/s 2降到8.99×10-8 m/s 2,变化值区间从(-74.20~66.28)×10-8 m/s 2降到(-21.79~27.70)×10-8 m/s 2,数据离散程度得到有效压缩,并能压制高频信号和局部噪声,孕震区域内重力变化时空演化趋势更加连续,便于异常特征的识别。场源区视密度变化显示有一个明显的NW-SE向物质迁移过程,在经过震中位置后逐渐收缩,在震中位置形成一个“孤岛”形态。孕震过程中正负变化分界线从SW-NE向转为NW-SE向,在分界线与构造走向一致后随即发震。展开更多
文摘Based on the analysis of coseismic deformation in the macroscopic epicentral region extracted by Differential Interferometric Synthetic Aperture Radar (D-InSAR), and combined with the seismic activity, focal mechanism solutions of the earthquake and field investigation, the characteristic of coseismic deformation of MS=8.1 western Kunlunshan Pass earthquake in 2001 was researched. The study shows that its epicenter lies in the northeast side of Hoh Sai Hu; and the seismogenic fault in the macroscopic epicentral region can be divided into two central deformation fields: the west and east segments with the lengths of 42 km and 48 km, respectively. The whole fault extends about 90 km. From the distribution of interferometry fringes, the characteristic of sinistral strike slip of seismogenic fault can be identified clearly. The deformations on both sides of the fault are different with an obviously higher value on the south side. In the vicinity of macroscopic epicenter, the maximum displacement in look direction is about 288.4 cm and the minimum is 224.0 cm; the maximum sinistral horizontal dislocation of seismogenic fault near the macroscopic epicenter is 738.1 cm and the minimum is 551.8 cm.
基金National major basic-theory planning project Mechanism and Prediction of Strong Earthquake (95130105) and the Key Project from China Seismological Bureau (95040803).
文摘Deterministic, probabilistic and composite-grading methods are used to get the possible locations of strong earth-quakes in the future in Norwest Beijing and its vicinity based on the quantitative data and their accuracy about active tectonics in the research area and by ordering, some questions in the results are also discussed. It shows that the most dangerous fault segments for strong earthquakes in the future include: segments B and A of the southern boundary fault of the Yangyuan basin, the southern boundary fault of the Xuanhua basin, the east segment of the southern Huaian fault and the east segment of the northern YanggaoTianzhen fault. The most dangerous area is YangyuanShenjing basin, the second one is TianzhenHuaianXuanhua basin and the third dangerous areas are WanquanZhangjiakou and northeast of Yuxian to southwest of Fanshan.
文摘利用1989—1996年滇西地震预报实验场绝对重力和相对重力观测资料,采用逐年差分和多年累积的方法,分析滇西地震预报实验场内部不同时间尺度的重力场演变特征及其与丽江地震在时空上的对应关系,结果表明:①1992年以前,研究区内部重力场变化平稳,1993年出现局部变化,1995年变化急剧加大,震后快速反向调整,变化量值基本与震前多年累积相当,重力场演化特征与丽江地震存在高度时空对应关系,表明该时段重力场变化为丽江地震的孕震特征。②研究区差分及累积重力场动态演化过程中,在川滇菱形块体与滇西块体边界产生重力变化梯度带,表明这2个块体构造活动剧烈。③沿红河断裂带出现(-60~90)×10-8 m/s 2的重力变化高梯度带,其走向与红河断裂构造高度一致,反映区域重力场变化受主要活动构造控制,是地下深部壳幔物质运移的表现。
文摘针对相对重力观测过程中可能受到环境等因素影响而出现高频信号和局部异常的情况,以2021年漾濞6.4级地震前重力变化为例,通过时空平滑约束重构重力变化数据,对比重构前后重力变化情况。基于球坐标系下六面体模型模拟场源体介质,反演场源视密度变化,分析场源区介质密度演化特征。结果显示:观测数据经过时空平滑重构后,在不改变总体变化趋势的情况下,标准差由17.86×10-8 m/s 2降到8.99×10-8 m/s 2,变化值区间从(-74.20~66.28)×10-8 m/s 2降到(-21.79~27.70)×10-8 m/s 2,数据离散程度得到有效压缩,并能压制高频信号和局部噪声,孕震区域内重力变化时空演化趋势更加连续,便于异常特征的识别。场源区视密度变化显示有一个明显的NW-SE向物质迁移过程,在经过震中位置后逐渐收缩,在震中位置形成一个“孤岛”形态。孕震过程中正负变化分界线从SW-NE向转为NW-SE向,在分界线与构造走向一致后随即发震。
