共查询到20条相似文献，搜索用时 718 毫秒
1.
2020年1月19日新疆维吾尔自治区伽师县发生MS6.4地震，此次地震为N倾逆冲兼少量走滑型地震，地震的发震构造是南天山柯坪塔格逆冲推覆体最南缘的柯坪断裂，伽师地震的震中位于喀什-伽师流动重力观测网和中国大陆构造环境监测网络GNSS观测网监测区域内。文中选取2015—2021年的流动重力和GNSS观测资料开展分析。采用绝对重力点约束流动重力数据，并进行全网经典平差计算，进而获得重力场变化图像；基于GNSS数据通过GAMIT/GLOBK软件解算获得研究区的运动速率，借助位移与应变的偏导关系获取水平视应变场分布图。之后，分别研究了孕震区的重力场和应变场的变化特征，并综合探讨了孕震区的重力场、 GNSS形变场特征与伽师MS6.4地震孕震过程的关系。研究表明：1)一年时间尺度的重力场时变图像较好地反映了伽师MS6.4地震附近区域重力场的系统演化过程，重力变化零等值线拐弯处及“四象限”特征可为地震预报提供有益参考。2)重力场累积变化反映出伽师MS6.4地震前的重力场变化受到区域大断裂的控制，研究区一系列中强震... 相似文献
2.
利用四川地区2010 ～ 2013 年流动重力观测数据作出的重力场动态变化图像和重力段差时序变化图像,对芦山7. 0 级地震前后的重力场动态演化特征进行了研究,结果表明:震前重力场经历了约3 年的重力增大和约1 年的减小变化,重力变化呈“上升→加速上升→减速上升→加速下降→减速下降”特征; 芦山地震发生在重力场变化由下降转为上升的回调过程中;震后重力场变化以较快的速度恢复到接近震前状况,并出现重力正值变化异常区域;临震前震中区域重力场变化数值较小,构造带活动速度变慢。 相似文献
3.
本文在考虑全球陆面数据同化系统陆地水储量变化影响后,利用2002年4月—2015年4月GRACE卫星RL05月重力场模型获取了2011年日本MW9.0地震震中及其周边区域的重力场信息;然后给出了日本及其周边2003—2015年的年度累积重力变化和差分重力变化,并且利用经验正态函数方法深入分析了该地震过程中同震重力变化对区域重力场的贡献. 结果显示:日本MW9.0地震前研究区域出现了幅值高达2×10-8 m/s2的异常重力变化,其同震效应的时间和空间特征均出现在第一模态,且同震重力变化和震后区域重力场变化特征显著,这充分表明该地震对区域重力场的影响显著. 相似文献
4.
5.
利用2011年8月11日新疆伽师MS5.8地震前喀什—伽师流动重力网2009年4月至2011年7月的重力复测数据,绘制区域重力场差分和累计动态变化图像。分析表明:(1)地震发生在断裂带重力变化正、负异常密集区的零等值线附近和重力场的反向恢复变化过程中;地震发生前一年出现"闭锁"的重力变化特征;(2)区域重力场差分变化反映出震前伽师—西克尔地区地壳物质运动信息;区域重力场的"平静—活跃"过程,反映出伽师—西克尔区域重力场短期局部构造运动;区域重力场累计动态变化反映出地壳运动的背景特征;(3)地震震前重力变化等值线平行于断层分布,临震时重力变化等值线近垂直于断层,是一个显著的重力特征。 相似文献
6.
基于GRACE卫星时变重力数据,利用小波多尺度分解方法,分析研究了芦山MS7.0地震前重力场的时空动态演化特征.结果表明,雅安地区震前卫星时变重力场具有明显的重力变化信息.卫星时变重力场在时间域表现为,累积重力场和差分重力场存在较强的规律性动态变化,以2003—2004年均值为基值的2009—2012年的变化特征与2005—2007年的变化特征具有较好的相似性,以2009年均值为基值的2009—2012年即芦山地震前4年,芦山震区的时变重力场呈现上升→减速上升→加速上升以及上升→轻微下降→快速上升的变化特征;卫星重力场在空间域表现为,震中位置由靠近重力场正变化的中心→接近重力场正变化边缘→接近重力正变化四象限分布中心的变化特征.因此,芦山地震的重力场动态变化信息和波场分离结果符合逆冲推覆兼走滑型地震引起的区域变形特征. 相似文献
7.
8.
GRACE卫星重力在地震研究中的应用进展 总被引：1，自引：0，他引：1
地球重力场恢复与气候实验卫星(GRACE)在运行期间提供了大量的地球时变重力场观测数据,在大地测量、地球环境变化等领域有非常广泛的应用.在固体地球科学研究中,GRACE重力场数据被广泛应用于天然地震研究,由于地震过程中存在大范围的质量迁移,大型地震引起的重力变化可以被GRACE卫星探测到.同时GRACE记录的地震同震及震后长期的重力场变化对反演地震震源参数也起到了帮助作用.本文从GRACE卫星重力场在地震研究中的应用出发,在回顾了GRACE卫星重力在地震应用的主要进展的基础上,总结了以地震研究为应用目标的数据处理方法与流程,为地震同震及震后卫星重力数据处理提供了技术思路.本文结合前人在2004年M_W9.3苏门答腊地震、2010年M_W8.8智利地震、2011年M_W9.0日本东北地震的研究成果,针对地震重力变化的同震观测、震后观测、间接观测等领域,总结了GRACE卫星重力的主要应用进展,提出了其中涉及的GRACE数据处理与地震综合解释的主要研究问题.在总结技术研究进展的基础上,本文以2004年M_W9.3苏门答腊地震为研究对象,对GRACE卫星重力数据序列进行处理,得到该地震的同震重力变化特性,并以此为基础进行了地震同震重力变化的特征分析.在回顾和总结的基础上,本文结合GRACE-Follow on计划的优势,提出未来GRACE卫星应用于地震研究的发展展望. 相似文献
9.
对2012年3月9日新疆洛浦Ms6.0地震前陆态网络GPS连续跟踪站数据与喀什—伽师2010年7月～2012年3月期间重力复测数据进行计算分析.结果表明：（1）断层两端运动速率不同,为应力积累创造了条件;（2）地震发生前监测区出现区域性的重力异常变化高值区,区域重力场等值线与发震断裂走向平行;震前区域重力场出现增强—减弱—增强过程. 相似文献
10.
11.
12.
WEI Shou-chun ZHU Yi-qing ZHAO Yun-feng ZHANG Song LIU Fang LI Rui GAO Duo-wen 《地震地质》1979,42(4):923-935
The Hutubi MS6.2 earthquake of December 8, 2016 is a pure thrust event in the northern Tianshan thrust fold belt. The earthquake occurred between the Qigu Fault and the Junggar southern margin fault, which are both thrust faults. Based on mobile gravity measurements from 2013 to 2018 in the northern Tianshan, the gravity net adjustment was accomplished using Urumqi absolute gravity observation point as the datum, and the absolute gravity value of surface observation points were obtained. In order to eliminate the seasonal effect on gravity variation, the paper uses the observation data in May per annual as studying objects and obtains the temporal-spatial dynamic evolution images of gravity field differences in the northern Tianshan at different time scales as well as the time series of gravity variation of some points in the adjacent area of the epicenter. The characteristics of regional gravity variation before and after the Hutubi MS6.2 earthquake on December 8, 2016 and their relations are analyzed systematically. The results show that: 1)The gravity variations in the study area are dramatic in generally, and the contours of gravity variation are consistent with the main faults basically. There was a four-quadrant distribution near the epicenter before the earthquake, and the Hutubi MS6.2 earthquake occurred near the center of the four-quadrant distribution and at the turn of the gravity variation contour. The three years' cumulative gravity variation before the earthquake and the gravity variation after the earthquake are inversed, and the variation amplitudes are equivalent, suggesting that the MS6.2 earthquake has released the stress and the energy accumulated before the earthquake. 2)This paper focuses on the analysis of gravity variation at the observation points on both sides of the Junggar southern margin fault near the epicenter. Regional gravity variation and gravity time series show that gravity variations at the same side of the Junggar southern margin fault are basically consistent, however, gravity variations at the different sides of the Junggar southern margin fault are different from each other obviously, indicating the difference of material migration laws in different structural regions. In addition, the strain energy accumulated in the epicenter is basically released after the earthquake, and the area nearby the epicenter tends to be stable. 3)The Hutubi MS6.2 earthquake occurred near the center of the four-quadrant and at the turn of the high-gradient zone of gravity variation, reflecting the location of strong earthquake is related to the distribution of four-quadrant of regional gravity variation, the high-gradient zone of regional gravity variation and its turn. It has a unique advantage in determining the location of strong earthquake using gravity variation results. The regional spatial-temporal gravity variation before the earthquake is manifested as a systematic evolution process of “steady state→regional gravity anomaly→four-quadrant distribution→earthquake occurring in the reverse process”. Studying the temporal-spatial evolution characteristics of gravity field before and after Hutubi MS6.2 earthquake has important practical significance for understanding the occurrence law of large earthquakes and capturing the precursory information of earthquakes. 相似文献
13.
14.
通过对1992~2008年间各期观测资料进行全时空扫描,分析华北地区网区重力场的演化特征,总结震前异常的形态、持续时间和变化幅度,指出重力场空间变化易于发生地震的部位,并对一些问题进行讨论。结果显示:华北地区重力场总体变化不具明确规律性;大量测点存在明显的背景性趋势性异常变化;重力场变化与网区及周边地区中强地震的活动联系密切,较明显的重力场异常反应多发生在震前2年左右时间,且常伴有大面积高值异常区出现。重力变化"0"线、高梯度带、异常中心(含极值)附近是重力场空间变化易于发震的部位。 相似文献
15.
应用重力变化平面图和各点时序变化曲线．结合网区及周边地区震例,对邢台网重力场震前异常特征进行了研究。结果显示．网区重力场存在整体单调上升变化背景;重力场变化同周边地震活动水平明显相关;震前伴有网区重力场变化加速或转折过程,平面图出现大面积高值异常区。 相似文献
16.
Xianshuihe Fault, a main strong earthquake activity belt in southwest China, begins from Ganzi in the northwest, passes through Luhuo, Daofu, and Kangding, and then extents along the Dadu River valley. The fault is divided into two parts at Shimian, one part turns to south and converses to Anninghe Fault extending further to south, the other part, continuing to extend to southeast, cutting through Xiaoxiangling and then changing to Daliangshan Faults in the north of the Yuexi Basin, has the length of about 400km. Since 1700AD, there have happened 22 earthquakes larger than magnitude 6.0 and 8 earthquakes larger than magnitude 7.0. In this paper, we systematically collated and computed the gravity repetition measurement data along the Xianshuihe fault zone since 1988, and by referring to the anomaly index of gravity field of the predecessor achievements, analyzed the spatial-temporal variation of the regional gravity field and the relation to the occurrence of ≥ MS5.0 earthquakes. The mechanism of the regional gravity changes is further studied, and also the implication of strong earthquake risk because of the dynamic variation of gravity field in the near future is discussed.The results show that:1)The mobile gravity observation has the ability to detect crustal activity and MS ≥ 5.0 earthquake events. 2)There is definite correspondence between interannual gravitational field change and the 8 earthquakes among the 13 MS ≥ 5.0 earthquakes occurring in the surveying area since 1988, which can be determined according to the change of interannual gravitational field. Three M ≥ 6.0 earthquakes occurred 3~4 years after the abnormal image was developed, 4 earthquakes that occurred in the region of no data available were not determined. 3)A significant feature of the spatial-temporal variation of the regional gravity is a north-south run-through image before 2004, and characterized by the alternatively positive or negative variation in different year, the earthquakes of MS ≥ 5.0 occurring in this period were not distributed along the fault. Gravity variation magnitude indicates that there were two similar crustal material movement waves before 2004, corresponding to the course of earthquake space-time distribution from strong to weak in the study area. After 2010, the variation image shows that the local positive and negative zones are concurrent within a year, different from the image before 2004, and earthquakes of MS ≥ 5.0 basically occurred on the fault. It is believed that the variation of gravity field since 1988 and the seismic distribution fit with the geodynamic mode of strong and weak stages of the northeast motion of Indian plate. According to the conclusion we can try to optimize gravity anomaly index. After the Kangding earthquake in 2014, the north segment of Moxi Fault was still subject to negative high value changes till 2017 and then the gravity variation was further developed to a four quadrant distribution image. Based on the analysis of this paper and the previous variation trend of gravity field, we believe that the north segment of Moxi Fault has the background of medium-long term, strong or large earthquake risk. 相似文献
17.
CHARACTERISTICS OF MULTI-SCALE GRAVITY FIELD VARIATION AND SEISMOGENIC MECHANISM ANALYSIS IN THE SOUTHEASTERN TIBETAN PLATEAU 
下载免费PDF全文
下载免费PDF全文 CHEN Zhao-hui MENG Xiao-hong ZHANG Shuang-xi LIU Jin-zhao WANG Tong-qing ZHANG Pin WEI Shao-gang 《地震地质》2019,41(3):690-703
As the most basic geophysical field, the earth gravity field has achieved wide attention, and its spatial anomaly characteristics and dynamic variation can provide important scientific basis for studying the internal structure and dynamics of the Earth. Based on the mobile gravity observation data of the southeastern Tibetan plateau from 2013 to 2016, the dynamic variation tendency and anomaly characteristics of the regional gravity field in different temporal resolutions are obtained before and after the Ludian and Jinggu earthquakes in the study area respectively. The method of wavelet multi-scale decomposition is used to analyze the relationships of gravity field variation with the earth movement, material density change, and strong earthquake preparation. The deep material variation, dynamic process and the mechanism of earthquake inoculation in the southeastern Tibetan plateau are further discussed. Results indicate that the gravity field variation in the source region before the Ludian and Jinggu earthquake respectively is characterized by obvious positive and negative anomalous transition zone and gradient zone that are consistent with the direction of fault tectonics, suggesting the strong crustal movement and mass migration during the earthquake incubation period. The result of wavelet multi-scale decomposition of the gravity field during the period from September 2013 to April 2014 shows that the gravity field variation at different depth and space scale in the crust and upper mantle of the southeastern Tibetan plateau is significantly correlated with seismic distribution and the location of active fault zone. This indicates that the earthquake inoculation in the study area is closely related to the fault movement and the distribution of material density in the crust and upper mantle, which may be affected by the complex deep dynamic process of the material migration in the crust and mantle. The characteristic that strong earthquakes always occur near positive and negative anomaly transition zones and gradient zones of gravity field change is preliminarily explained, based on the dynamic process of material migration in the crust and upper mantle of the southeastern Tibetan plateau. The research results of this paper have some reference value to the study on the earth movement and seismogenic mechanism. 相似文献
18.
本文介绍了容量限制分配方法的概念、交通量与车速的特点、容量限制分配方法的具体应用步骤和分配次数对分配结果的影响等。 相似文献
19.
地震前,地壳变形引起地球密度重新分布,从而使地球重力场发生某些特征变化。本文对1990年7月菲律宾8级、台湾6.1级两个强震前后的广州重力资料进行了调和分析及高、低频滤波等处理,并对提取出的重力前兆进行了可信度检验。结果表明强震前广州地区的重力变化具有O_1等主波潮汐因子波形畸变,量值下降至最低值然后在回升阶段发震的前兆异常特征。非潮汐重力变化在临震前3天开始出现明显的高频脉冲式异常信息,作者认为这是一种可信的具有清晰物理意义的地震短临前兆。 相似文献
20.
介绍流动重力历史资料清理流程、方法及获得的规范化成果,对1998年泾阳MS 4．8、2009年高陵MS 4．4地震前后的重力场变化进行分析,得到结论：①泾阳地震前后重力场变化满足“震前重力持续增强-震后反向恢复”的特征;②泾阳地震的发生可能与附近断裂活动有关,同时受华北块体应力场的作用;③高陵地震前后重力变化与泾阳地震前后重力变化具有一定的相似性,且位于渭河断裂附近,两个地震均受到渭河断裂活动的影响。 相似文献