共查询到20条相似文献，搜索用时 31 毫秒
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本文对玉树地震前后的热异常多参量变化进行分析研究,主要包括长波辐射（Outgoing Longwave Radiation）,地表温度（Land Surface Temperature）,NCEP地面气温（National Center for Environmental Prediction）和地下水温。研究结果证实玉树地震前确实存在热异常现象。在多参量中,地下水温最早出现异常并且异常持续时间最长;其次出现热异常的是反映地表介质辐射属性的长波辐射;地表温度出现热异常的时间要晚于长波辐射;NCEP地面温度反映了一定垂直厚度的平均大气温度,因此最晚出现热异常现象。同时,玉树地震前的多参量热异常区域都位于震中南部或西南部。 相似文献
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以2011年8月11日在伽师—阿图什交界处发生的5.8级地震为例,利用MODIS的LST产品数据,采用STL分解法有效地去除地表温度时空数据中的年变趋势及季节因素周期性的影响,对其余的残余项进行GESD异常检测,并分析2008年1月1日至2013年1月1日的LST异常及其他地震的关系数据,研究结果表明:(1)地表温度的变化具有明显的时空变化趋势;利用STL分解法可以看出震前存在明显的热红外异常,增温现象经历了"出现-扩大-分散增温-增温幅度达到极值-消失-发震"等几个阶段。(2)发震前四个月研究区周围存在明显的热红外异常,2月10日发震断层周围出现大面积异常,异常特征持续2个月后的4个月发震,峰值距发震时刻时间间隔较长。(3)余震分布与断裂带和热红外异常分布特征相关,震后大部分余震主要分布在主震发生的震前出现热红外异常的断裂带附近。(4)通过对比同地区相似震例发现,本次地震与2018年9月4日伽师县MS5.5地震的热异常特征有许多共同点,其中相同的峰值距发震时刻的时间间隔具有一致性,为震前热红外异常特征的归纳提供典型的参考信息。该次地震热红外异常显著,进一步验证了... 相似文献
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以2000年以来6.4级以上地震为例,研究了腾冲地区潜热通量（SLHF）在这些震例发生前后的变化特征。结果表明：腾冲地区的SLHF动态,不但在其附近发生强地震前常出现异常,而且对周边较远的强地震前也会发生异常反应;异常出现时间大都在震前1个半月以内,汶川地震前异常出现较早,发生在震前2个月之前,这可能与汶川地震震级高影响范围大有关;异常幅值与震级有关,震级越大,异常表现越强。 比如芦山7.0级地震、缅甸7.0级地震和汶川MS 8.0地震前,腾冲地区SLHF异常幅度很大,远远超过最大参考值,而姚安6.5级地震和宁洱6.4级地震前异常幅度就相对小一些。腾冲地区SLHF异常与周围强地震的发生有较好的相关性,一方面与腾冲地区的活动断裂发育、现今构造变形强烈有关,另一方面可能是由于腾冲地区火山活动强烈,温泉广泛发育,水热交换迅速,对周边构造活动感应灵敏所致。 相似文献
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主要利用统计方法建立红外亮温背景场及异常检测模型,来提取2012年华北地区的红外亮温异常信息,并对2012年唐山4.8级地震和宝坻4.0级地震前的异常演化过程进行分析研究。结果表明:背景场方面,红外亮温的多年月背景场具有夏高冬低的年变特征,符合季节变化规律,红外亮温与高程呈负相关关系;基于历年同期亮温偏移指数K值方面,2012年5月28日唐山4.8级地震震前在唐山断裂带以南存在明显强烈的K值异常,在震前8小时达到最大约3.3。6月18日宝坻4.0级地震在震前也存在红外亮温异常现象,但是较弱。 相似文献
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QI-QI L 《地震学报(英文版)》2000,13(2):203-209
This paper used the thermal infrared data of the satellite NOAA-AAVHRR of the north part of North China (113°～119° E, 38°～42° N), and processed the remote sensing data through radiation adjustment, geometric adjustment and so on by the software ＂The Monitoring and Fast Process System of Earthquake Precursor Thermal Infrared Anomaly＂, inversed the earth surface temperature. Some disturbances effect had been excluded, and thermal infrared temperature anomaly had been extracted by the picture difference method. The Zhangbei MS=6.2 earthquake is used as the example in the paper, so that in the paper thermal infrared characteristics on time-space before earthquake and the relationship between the anomaly and the earthquake prediction have been summarized.Within more than ten days before the Zhangbei earthquake, the thermal infrared anomaly had emerged widely along Zhangjiakou-Bohai seismic belt, and the anomalous region seemed like a belt and it is also consistent with the tectonic background there; the anomaly expanded from the outside toward the earthquake focus, but the focus lay at the edge of the thermal infrared region. So it is possible to explore a new anomaly observation method for earthquake prediction by observing and studying the satellite thermal infrared anomaly before big earthquakes happen. 相似文献
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以中国静止气象卫星FY-2C/2E红外遥感资料为依据,采用小波变换与功率谱相对变化法对2014年10月7日云南景谷MS6.6地震进行震例数据处理和分析。结果显示:震前热异常具有明显时空特征,2014年8月上旬震中及其周围区域出现热红外异常,异常区范围随时间逐渐扩大、幅度陡增;8月30日左右异常面积达到最大,异常持续时间近一个月,异常幅度最大值达到平均值的14倍多,最大值45天后发生地震;该次地震热红外异常特征显著,容易识别,可作为一种识别地震热异常信息的判据,进一步验证卫星热红外异常在地震预判方面的作用。 相似文献
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应用中国静止气象卫星FY-2E红外遥感资料对2013年甘肃岷县漳县6.6级地震前的热红外异常信息进行研究,结果表明：由地震黑体辐射热异常时空演化图分析知,中强地震前,往往会有较大范围的热异常演变,热异常大面积沿断层分布,震中位置往往位于边界或热异常变化最大处.对比实时的长波辐射涡度场变化,能更好的对应未来地震的发震区域,涡度异常经常分布在震中边界. 相似文献
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TWO DIMENSIONAL MODEL ON RELATION BETWEEN THERMAL ANOMALY BEFORE WENCHUAN EARTHQUAKE AND TECTONIC STRESS 
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下载免费PDF全文 ZHU Chuan-hua SHAN Xin-jian ZHANG Guo-hong JIAO Zhong-hu ZHANG Ying-feng LI Yan-chuan QIAO Xin 《地震地质》2019,41(6):1497-1510
It has been reported that there is thermal anomaly within a certain time and space preceding an earthquake, and previous research has indicated potential associations between the thermal anomaly and earthquake faults, but it is still controversial whether physical processes associated with seismic faults can produce observable heat.Based on rock experiments, some scholars believe that the convective and stress-induced heat associated with fault stress changes may be the cause of those anomalies. Then, did the thermal anomaly before the Wenchuan earthquake induced by the fault stress change?It remains to be tested by numerical simulations on the distribution and intensity of thermal anomalies. For example, is the area of thermal anomaly caused by the fault stress changes before the earthquake the same as the observation?Is the intensity the same?To clarify the above questions, a two-dimensional thermo-hydro-mechanical(THM)finite element model was conducted in this study to simulate the spatial and temporal variations of thermal anomalies caused by the underground fluid convection and rock stress change due to the tectonic stress release on fault before earthquake. Results showed that the simulated thermal anomalies could be consistent with the observed in magnitude and spatio-temporal distribution. Before the Wenchuan earthquake, deformation-related thermal anomalies occurred mainly in the fault zone and its adjacent hanging wall, which are usually abnormal temperature rise, and occasionally abnormal cooling, occurring in the fault zone after the peak temperature rise. In the fault zone, the thermal anomaly is usually greater than the order of 1K of the equivalent air temperature and is controlled by the combined effect of fluid convection and stress change. The temperature increases first and then decreases before the earthquake. In the hanging wall, it's weaker than that of the fault zone, mainly depending on the convection of the fluid. The temperature gradually increases before the earthquake and is dramatically affected by the permeability. Usually, only when the permeability is larger than 10-13m2, can the air temperature rise higher than 1K occur. The results of this study support the view that fluid convection and stress change caused by fault slip before the earthquake can produce observable air temperature anomalies. 相似文献
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通过分析昭苏6．1级地震序列特征、震源与介质破裂特性、震源环境与历史地震活动类比及区域地震和前兆资料的异常变化等，对该震前的区域地震活动背景、震后的震情趋势等有了较为细致的了解和判定。主要结果有：①在2003年新疆境内中强地震成组活动的背景下，于现代地震活动很弱的昭苏盆地内发生了6．1级地震；②6．1级地震为主一余型地震序列，震后序列衰减正常；③主震震源机制解结果与现代区域构造应力场特征吻合，表明构造活动具有明显的继承性，并对地震活动有着控制作用；④震源区域构造应力释放充分，区域应力场处于相对稳定的调整状态。综合各类分析结果后认为，震区发生更大地震的可能性很小。 相似文献
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SONG Dong-mei XIANG Liang SHAN Xin-jian YIN Jing-yuan WANG Bin CUI Jian-yong 《地震地质》2019,41(6):1511-1528
There are many factors related to the variations of TEC, and the changes of TEC caused by earthquake only occupy a small portion. Therefore, it is vital how to exclude the ionospheric interference of non-seismic factors accurately in the process of seismic ionospheric anomaly extraction. This study constructed a TEC non-seismic dynamic background field considering the influence of solar and geomagnetic activities. Firstly, the TEC components of half-year cycle and annual cycle are extracted by wavelet decomposition. Then, it establishes a regression model between TEC in which periodic factors are removed and solar activity index, geomagnetic activity index with SVR method(support vector regression)in non-seismic period. Finally, based on the constructed model, the solar activity index and geomagnetic activity index is used to reconstruct aperiodic components of TEC in earthquake's period. From the reconstructed aperiodic components of TEC plus the half-year periodic components and annual periodic components of TEC in the same period, the non-seismic dynamic background field is obtained. Comparing the residuals relative to original TEC values in non-seismic dynamic background field and traditional sliding window background, there are apparent monthly periodic change and semi-annual periodic change in the residuals of sliding window background, which can have obvious impacts on the subsequent seismic ionospheric anomaly detection. In order to test the validity of seismic TEC anomaly detection based on the background field construction method, this paper investigated the long time series TEC anomalies near Wenchuan city(30°N, 100°E)from March 1 to September 26 in 2008. It is found that under the condition of non-seismic disturbance such as solar activity and geomagnetic activity, TEC abnormal disturbance is rarely detected by non-seismic dynamic background field method, when compared with the traditional sliding time-window method. And before the earthquake, more TEC anomalies were detected based on the proposed method, also, they were more intense than those extracted by sliding window method. Therefore, the TEC background field construction method based on SVR(support vector regression)has superiorities in both system errors elimination, which are caused by solar, geomagnetism, the non-seismic ionospheric disturbance events and periodic fluctuations of TEC, and in reducing the false alarm rate of seismic TEC anomaly. Moreover, it can also improve the seismic TEC anomaly detection ability. In addition, this paper analyzed the time-spatial distribution of TEC anomaly before three earthquakes on May 12, August 21 and August 30, 2008. They were mainly negative abnormal perturbations and often distributed on the equatorial side of epicenter. 相似文献
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北部湾6.1,6.2级地震的前兆异常 总被引：1，自引：0，他引：1
通过对北部湾６．１，６．１级地震前的震兆分析，认为地震是在区域地震活动出现中期异常背景的情况下发生的，前兆观测的趋势异常较为突出，但短临异常极少，地震活动性和前兆观测手段的趋势异常变化具有稳定性和准同步性，反映了震前区域应力场的变化。 相似文献
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１９９３年１１月１８日及１９９８年４月４日在天津市宝坻县和唐山强震区的钱营分别发生ＭＬ４．４级和ＭＬ５．０地震各一次,在这两次中等地震前,分别显示出中期地震活动空间分布及短临性水化学观测异常,其表现形式明显不同。本文在客观介绍上述异常的基础上,结合它们所属的地震类型、发震的构造背景以及相关地震的分析比较,对它们震前的异常表现形式不同的原因进行分析和探讨,并初步得出中等地震前产生不同异常显示的基础手 相似文献
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基于新疆分量式钻孔应变异常类型的地震强度预测研究 总被引：1，自引：0，他引：1
研究了钻孔应变年变畸变型异常及指数型异常对地震震级的估计问题,认为年变畸变型异常对大震有较高的映震性能.研究了异常幅度和震中距、时间分布和震级关联问题,结果表明,在时间小于45天时,震级和发震时间呈反比,在时间大于45天时,震级和发震时间呈正比. 相似文献
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以中国静止气象卫星FY-2C/E亮温资料为数据源,采用功率谱相对变化法对2013年4月20日四川芦山7.0级地震进行震例数据处理和分析。结果显示:震前热异常具有明显时空特征,2013年3月底震中及其北部区域出现热红外异常,异常区范围随时间逐渐扩大、幅度陡增;4月13日左右异常面积达到最大,随后缓慢收缩,异常持续时间近一个月,异常幅度最大值达到9倍多,最大值后3天发震。该次地震热红外异常特征显著,易于识别,进一步验证了卫星热红外异常在地震预判方面的作用。 相似文献
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以小波变换和功率谱估计为研究方法,使用中国静止气象卫星热红外亮温数据,研究了2017年11月18日西藏米林MS6.9地震前的热辐射情况。结果发现震前4个月出现热红外异常,其后续演化方向与相关区域的断裂走向非常一致。在8月10日左右异常面积达最大,相对功率谱大于6倍的面积约为20万km^2,9月20日左右消失。分析相同频率2016年同期数据,结果显示在震中周围并未出现显著异常。时序曲线分析表明在8月12日相对功率谱达到峰值,为平均值的20倍,98天后米林地震发生;从7月4日到9月7日,地震当年相对功率谱偏离背景值和标准差,持续时间为65天。西藏地区的强震热红外异常表现出与地热资源分布较为一致的特征及特征周期相对较长的特点,为判定西藏地区的震情积累了一些经验。 相似文献
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对比分析利用涡度距平法提出的2022年1月8日青海门源 MS6.9 地震震前射出长波辐射(OLR)短期异常分布和震后InSAR技术提取的门源地震同震形变空间分布,结果显示,震前红外辐射增强区与InSAR同震破裂形变区的空间位置基本吻合,扩展形式基本相似(同震破裂形变区分布在红外辐射异常区内部)。在震前的全国范围OLR空间分布上,仅青海德令哈—西宁—甘肃武威一带出现了呈“哑铃”状近WE向展布的OLR热辐射增强区,空间可辨识度高,OLR异常时空演化过程遵循了岩石应力加载破裂过程中的热异常规律,显示热异常变化与应力变化存在关联; InSAR技术提取的同震形变同样位于肃南—祁连断裂(俄堡段)、托莱山断裂和冷龙岭断裂的交汇区。InSAR同震形变结果揭示了地表形变以水平方向为主,断层运动具有典型的走滑变形特征。InSAR同震形变结果为红外遥感反映地震形变提供可检验的地质实体监测证据,验证了门源地震前辐射增强异常是地震构造地应力强度变化的遥感物理参量反映。 相似文献
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分析了晋冀蒙交界地区3次6级以上地震前的电场变化,发现各台异常具有如下相似特征:1)异常形态绝大部分为阶变类型,即突升(或突降)-转平-突降(或突升)型;2)异常具有非常明显的短临特征,统计的10次异常中有9次在震前1个月内存在异常;3)异常的持续性,即地震发生后异常持续一段时间就突然恢复到原来的水平,同震结束的现象较少;4)单测向异常,即强震前一般只在台站的1个测向出现异常,文中研究的异常信息多出现在NW或EW方向,与震中方位有关;5)异常幅度与震级及震中距密切相关。最后,通过与水位资料进行对比分析,认为这类异常与地下流体的运移关系密切 相似文献