2010年西藏聂荣MS5.7和MS5.5地震前后热红外异常分析

选取2010年3月24日西藏聂荣M_S5.7和M_S5.5地震前后的中国FY-2E静止气象卫星热红外遥感亮温和长波辐射数据, 对红外辐射数据采用阈值法进行去云预处理, 基于Morlet小波方法计算地震前后的红外辐射功率谱变化, 探讨地震前后红外辐射异常演变规律及特征。 研究结果显示, 西藏聂荣地震前出现了亮温和长波辐射异常增强现象, 并且其异常持续时间和主要异常区域基本一致, 但亮温的异常幅度大于长波辐射的异常幅度。 本研究对于该区域利用热红外遥感数据进行地震研究具有重要的参考价值和意义。     

地表热红外辐射的小波分析及其在现今构造活动研究中的意义

地表热红外辐射的影响因素较多，不仅受到构造活动的影响，还受到大气、太阳以及植被等多种因素的干扰.如何排除这些因素的干扰，是热红外遥感用于研究断层活动或者地震活动的难点之一.从频率域看，地表热红外辐射主要存在3种频段：(1)高频, 周期小于1年的天气变化；(2)中频,以1年周期为主的太阳、植被与季节变化； (3)低频，大于1年周期的大气变化的长周期成份，地壳缓慢的运动引起的热辐射变化亦属于长周期变化.本文运用小波理论将地表热红外辐射分解为上述3个频率成份，并结合气象资料和地震活动进行综合分析.结果表明，低频成份的热异常更接近于断层活动所引起的热信息，能为断层或地震活动提供一定的指示信息.低频成份的高温异常区(条带)跟构造特征、地震活动密切相关.     

基于双树复小波包变换的地震信号分析方法

尝试性地将一种双树复小波包变换方法应用于地震信号分析中 .复小波包变换综合了实小波包变换与连续复小波变换各自的优点 ,不但能提取信号的相位信息 ,而且选取与被分析信号相频特性相匹配的复小波包 ,可以对信号产生更好的“聚焦”作用 .本文描述了一种双树复小波包变换算法 ,并给出了模拟信号及实际地震记录的分析实例 .研究结果表明 ,双树复小波包变换是分析具有非线性相位地震信号的一种较为有效的方法 .     

基于双树复小波包变换的地震信号分析方法

尝试性地将一种双树复小波包变换方法应用于地震信号分析中. 复小波包变换综合了实小波包变换与连续复小波变换各自的优点，不但能提取信号的相位信息，而且选取与被分析信号相频特性相匹配的复小波包，可以对信号产生更好的聚焦作用. 本文描述了一种双树复小波包变换算法，并给出了模拟信号及实际地震记录的分析实例. 研究结果表明，双树复小波包变换是分析具有非线性相位地震信号的一种较为有效的方法.      

2014年10月7日云南景谷MS6.6地震热红外异常

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。     

小波包变换中地震信号的结点序号到频带序号的转换算法

利用小波包变换对地震非平稳信号进行处理时,结点与频带之间存在"跳频"现象,基于小波包变换算法以及异或运算,对小波包树频带序号和结点序号的关系进行研究,明确信号子空间频带与小波包树结点的排列规律,同时提出一种从结点序号到频带序号的转换算法。基于MATLAB平台,以唐山(南北向)波为例,验证该算法的正确性。     

2016年3月21日甘肃金塔4.7级地震热红外亮温异常分析

使用中国静止气象卫星FY-2E/G红外遥感亮温产品为基础数据,针对2016年3月21日甘肃金塔4.7级地震前后出现在震中区附近的显著热红外异常,运用小波变换和相对功率谱法进行异常提取和资料分析,结果表明,地震热红外异常范围主要分布在震中以北的大范围区域,震前10天左右出现功率谱增强现象,随着时间推移,异常范围逐渐向北扩大,一直持续到震时,震后14天异常开始收缩并减弱。通过对比同地区相似震例发现,本次地震与2012年5月3日金塔5.4级地震的热异常特征有许多共同点,其中相同的特征周期可为热红外地震前兆特征的归纳提供典型的参考信息,同时可为建立区域热异常统计模型积累可靠的判定依据。     

小波包分解树结点与信号子空间频带的对应关系及其应用

小波包变换的Mallat分解算法可以把较宽的信号频带划分成相等带宽且互不重叠的窄频带,但由于信号子空间频带的频率大小并非按照分解树结点（node）编号的大小顺序排列,各个结点重构信号的频率范围不易判定. 本文通过分析小波包变换的Mallat分解算法与分解滤波器的关系,设定频带编号与结点编号间进行二进制转化的运算规则,得到了小波包分解树结点与信号子空间频带的对应关系,然后通过模拟信号进行了验证. 结果表明,本文给出的小波包信号子空间频带的排列规则是正确的.      

基于支持向量机和小波包的金属矿床地震数据去噪

针对深部找矿地震资料信噪比很低的问题,结合小波包和支持向量机的理论,提出了一种新的去噪算法.该算法首先从地震资料中找出噪声干扰极小的和噪声很强的数据,利用支持向量机进行训练学习,提取噪声和有效信号的样本特征.然后将地震资料实施小波包变换得到更加精细和不同频带的信号,利用支持向量机训练出的样本特征对小波包变换后的数据进行...     

基于LST年趋势背景场的地震热异常提取算法

地震发生前普遍存在的热红外辐射异常现象,是当前评估区域发震危险性的重要参数之一。然而,并非所有的地表红外异常都与构造活动或地震有关,如何排除非构造因素对地表热红外辐射的影响,从强噪声背景中提取微弱信号,是当前利用热红外遥感技术研究构造活动的难点。地表温度(LST)背景场是热异常提取的基础,而以往研究中所建立的背景场不能有效反映当年气候变化对其的影响,造成热异常提取精度受限。为此,文中在提取热异常的过程中对背景场进行了改进,结合地表温度时间序列的周期性特征,引入谐波分析,采用傅里叶逼近的方法拟合地表温度离散时序,从中提取其年趋势,建立1个动态的、同时包含局地信息和年际特征的、更加可靠的地表温度背景场;将其引入RST模型,基于"kσ"准则识别地震热异常信息;最终采用异常方向、异常强度和距离指数这3个指标对异常结果进行分析,验证算法的有效性。利用MODIS地表温度产品,基于所提算法对2008年汶川地震进行了再研究,结果表明:1)汶川地震前存在明显的热异常,沿龙门山断裂呈带状分布,持续时间较长;2)发震期无明显的异常现象;3)震后热异常的发生具有循环往复性,但异常幅度和影响范围明显缩小。与传统的空间温度均值RST算法异常提取结果相比,文中方法所提取的热异常在空间分布上与活动断裂带更为吻合,对异常的产生消散过程刻画更加细致,表明以地表温度年趋势作为地震构造热异常提取的背景场更加可靠。     

INVESTIGATION OF STATUS AND DEMAND ON PUBLIC SERVICE OF EARTHQUAKE DISASTER MITIGATION IN CHINA

In order to make a comprehensive and systematic evaluation of the status and demands of public service of earthquake disaster mitigation, we launched an investigation with Social Opinion Polling Center of National Bureau of Statistics on the current situation of public service of earthquake disaster mitigation and the demands for it in 2018. The investigation was conducted for 18~75-year-old residents for both urban and rural areas in 31 provinces of China mainland using the Computer Assisted Telephone Interview(CATI)method and 20 078 valid samples were received in total. The questionnaire mainly includes two parts: the current situation assessment and the demand survey. The assessment of public service status consists of five indicators: earthquake emergency drill, knowledge publicity of earthquake prevention and disaster reduction, acquisition of earthquake information, reliability of information released by earthquake agencies, and overall satisfaction. The results indicate that only 27.4% of public have participated the earthquake emergency drill, and 73.5% of public have learned some knowledge about earthquake prevention and disaster reduction in different level. It shows that rural residents have a lower level of scientific knowledge of earthquake disaster mitigation although the rural residents have a higher level of satisfaction. Meanwhile, 82.9% of the public are very concerned about earthquake-related information, and the earthquake information acquisition convenience score is 81.51 points(the full score is 100 points). At present, TV is still the most popular way to obtain the earthquake-related information, besides that, network and the new media app such as Wechat and Weibo play a more and more important role. In terms of the reliability of official information published by the earthquake administration, the score is 83.69 points which indicates that the public tend to believe in official departments. Furthermore, the degree of satisfaction evaluation of public service of earthquake disaster mitigation is marked 76.44 points which shows that there is still much room for improvement. The more educated the public, the less satisfied they are with the public service of earthquake prevention and disaster reduction. The results also show that 51.81% of the public are willing to obtain earthquake warning information at their own expense. As for the demand, the most expectative services for the public are post-earthquake rescue and reconstruction, earthquake warning, and house earthquake resilience test. The results of the investigation may provide some reference for the government to provide better services of earthquake disaster mitigation and to make scientific knowledge popularization in a more scientific way.     

一种综合统计方法——地震学参数异常总量分析

提出一种综合性的统计方法,地震学参数异常总量方法,该方法选取的研究区具有较好映震能力,并且具有明确物理意义的地震活动性参数,通过所选参数的异常总量进行统计分析,研究未来地震趋势估计.对研究区发生的14个震例分析发现,参数总量异常对研究区中强地震具有较好的对应关系,大震前常常出现明显的高值异常.分析认为,地震参数总量异常...     

The observation and research on pre-earthquake electromagnetic radiation information

By use of the specialized under ground electrodes as the sensor, the Experimental Multi-station Network observed Seismic Electromagnetic radiationsprior to the moderately strong earthquake. From the great number of electromagnetic anomalies recorded by the network continuously for about 10 years, it can be sure that the anomalies are related to earthquakes aboveM _s 5 within 300 km. The stronger the magnitude of the earthquake is, the better the relation is. The abnormal electromagnetic radiation information appears in a short-time before the moderately strong earthquake. The continuous automatic pen recording shows that the electromagnetic information is the waveform of the paroxysmal wave group, and has the features of undulating enhancement, amplitude in inversely proportion to epicentral distance, frequency increase, regional similarity of wave froms and directivity, etc.. It also contains some quantitative elements related to the parameters of the earthquake. The above characteristics and correlative elements can provide important bases for predicting the three elements of the earthquake. The Chinese version of this paper appeared in the Chinese edition ofActa Seismologica Sinica,15, 83–90, 1993. Associate Professor Da-Yuan CHANG and Teacher Feng CHEN have gave us a lot of help during the study.     

华东地区M_L≥4.0地震平静预测意义分析

用统计学上的χ~2检验方法对华东地区M_L≥4.0地震平静进行了统计检验,得出在较高的置信概率下可以将平静时间T≥140天作为平静异常的判别标准。总结了华东地区自1970年以来出现的平静异常,并分析了其对应中强地震的情况。研究表明,M_L≥4.0地震平静异常是华东地区中强震前的一种普遍现象。62.5%的平静异常后发生了M_S≥4.5地震;绝大多数平静异常前存在着地震活动的增强过程,多次活动增强后连续发生了平静异常且之后发生了M_S≥5.0地震。     

The earthquake-related disturbances in ionosphere and project of the first China seismo-electromagnetic satellite

Based on the case studies and statistical analysis of earthquake-related ionospheric disturbances mainly from DEMETER satellite, ground-based GPS and ionosounding data, this paper summarizes the statistical characteristics of earthquake-related ionospheric disturbances, including electromagnetic emissions, plasma perturbations and variation of energetic particle flux. According to the main results done by Chinese scientists, fusing with the existed study from global researches, seismo-ionospheric disturbances usually occurred a few days or hours before earthquake occurrence. Paralleling to these case studies, lithosphere-atmosphere-ionosphere (LAI) coupling mechanisms are checked and optimized. A thermo-electric model was proposed to explain the seismo-electromagnetic effects before earthquakes. A propagation model was put forward to explain the electromagnetic waves into the ionosphere. According to the requirement of earthquake prediction research, China seismo-electromagnetic satellite, the first space-based platform of Chinese earthquake stereoscopic observation system, is proposed and planned to launch at about the end of 2014. It focuses on checking the LAI model and distinguishing earthquake-related ionospheric disturbance. The preliminary design for the satellite will adopt CAST-2000 platform with eight payloads onboard. It is believed that the satellite will work together with the ground monitoring network to improve the capability to capture seismo-electromagnetic information, which is beneficial for earthquake monitoring and prediction researches.     

PRINCIPAL COMPONENT ANALYSIS AND LOCAL CORRELA-TION TRACKING AS TOOLS FOR REVEALING AND ANALYZING SEISMO-ELECTROMAGNETIC SIGNAL OF EARTHQAUKE

This study provides new seismo-electromagnetic data processing methods to extract the anomalous signals by combining the principal component analysis(PCA)and local correlation tracking(LCT)methods. The PCA method can separate signals of different frequencies by projecting them to different axes according to their energy. So it can solve the problems of identifying the relatively weak signals in strong interference background to a certain extent. The LCT method is more suitable for non-stationary signal processing compared with classical cross-correlation method. This method is based on the good spatial correlation between the magnetic field components of different ELF stations to pick up the correlation coefficient, so as to achieve the purpose of weak anomalies signals identification. As a case study of the M4.6 Jinggu earthquake in Yunnan, China, we investigated the electromagnetic data observed by ELF stations near the epicenter. First, we applied the PCA method to the magnetic-filed data and got the temporal variation of percentage of each principal component. The results indicate that the contribution of the second principal components, which may relate with the earthquake, increased significantly about a week before the earthquake. Then, we applied the LCT method to the magnetic-filed data processing as well, and the results of both north-south and east-west magnetic field components showed that local correlation coefficient saw anomalies about a week before the earthquake, which had a good corresponding relationship with the former results by PCA method. Both means for the same earthquake case got a consistent conclusion, which not only enhanced the reliability of the results, but also confirmed the effectiveness of two methods applied in the earthquake-related electromagnetic anomalies extraction. We also discussed the possible relationship between these anomalies and the earthquake. Although there are no direct evidence and supporting theories in terms of the relationship between abnormal electromagnetic signals and earthquakes at present, the studies in this paper may strengthen the understanding of seismoelectromagnetic phenomena and promote further research.     

Analysis of observations backing up the existence of VLF and ionospheric TEC anomalies before the Mw6.1 earthquake in Greece,January 26, 2014

The present work integrates ground-based ionosphere measurements using very-low-frequency radio transmissions with satellite measurements of the total electron content to draw common conclusions about the possible impact that the Mw6.1 earthquake that took place in Greece on January 26, 2014, had on the ionosphere.Very-low-frequency radio signals reveal the existence of an ∼4-day anomaly in the wavelet spectra of the signals received inside the earthquake preparation zone and a significant increase in the normalized variance of the signals prior to the earthquake (approximately 1 day before).Through total electron content analysis, it was possible to identify a clear anomaly from 15:00 until 20:00 UT on the day before the earthquake that appears again on the day of the earthquake between 07:00 UT and 08:00 UT. The anomalous values reach TEC1Sigma ∼4.36 and 3.11, respectively. Their spatial and temporal distributions give grounds to assume a possible link with the earthquake preparation. The geomagnetic, solar and weather conditions during the considered period are presented and taken into account.This work is an initial and original step towards a multi-parameter approach to the problem of the possible earthquake-related effects on the ionosphere joining observations made from both ground stations and satellites. A well-founded knowledge of these phenomena is clearly necessary before dealing with their application to earthquake prediction purposes.     

Triggering Mechanisms of Slope Instability and their Relationship to Earthquakes and Tsunamis

— Submarine and shoreline slope failures that accompany large earthquakes and large tsunamis are triggered by several mechanisms. Triggering mechanisms range from direct effects, such as inertial forces from earthquake shaking, to indirect effects, such as rapid drawdown that occurs when an earthquake-generated tsunami first approaches a shoreline. Soil shear strength also plays an important role in earthquake-related slope failures. Earthquakes change the shear strength of the soil by inducing excess pore water pressures. These excess pore water pressures change with time after the earthquake, resulting in changes in shear strength and slope stability with time. This paper reviews earthquake-related triggering mechanisms for submarine and shoreline slope failures. The variation in shear strength with time following an earthquake is examined and it is shown that delayed slope failures after an earthquake can occur as a result of changes in earthquake-induced excess pore water pressures and shear strength with time.     

气体受激增温的实验研究

试验结果基本证明了热红外温度异常与太阳照射、大气电场、大气成分密切相关。非极性气体如CO2 、CH4 的含量越高, 增温越大。而极性气体, 如水蒸气则相反, 含量越高, 增温越小。CO2 、CH4 含量高的大气, 其增温远远超过单纯由温室效应引起的增温, 其幅度可达10℃,而水蒸气引起的增温还没有单纯由其温室效应引起的高。