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1.
The relationship between Sacks body strain deformation at Beida No. 200 station in Changping and tidal solids,atmospheric pressure and water level is analyzed in this paper. Sacks body strain deformation data before the M_S8. 0 Wenchuan earthquake is studied based on the analysis of the interference. The short-impending anomaly of the body strain deformation is considered to be reliable. The anomaly characteristics conclude:( 1) The trend anomaly as extensional change of the body strain deformations on a quasi 1 year time scale before the Wenchuan earthquake was recorded, and the accumulative amount was about 4000 × 10~(-9). Correspondingly,the short-term precursor of earthquake was manifested as an extensional abrupt change.( 2) The extensional intermittent anomalous abrupt change was recorded by body strainmeters between March1 and May 7 in 2008.( 3) Four compressional abrupt changes were recorded in the intermittent distortions recorded between April 13 and May 11.( 4) High frequency components were increased in the distortion process in May 1 to 3,5,7,and 9 to 12,caused by slow earthquakes before the Wenchuan earthquake according to wavelet analysis. The abnormal phenomena are summarized and the mechanics discussed in this paper. Strain solid tide distortions in body strain observations,the continuous repeated extensional and compressional abrupt changes accompanying these distortions,and the increase of high frequency components can be regarded as the index of short term and impending earthquake prediction,based on analysis of interference factors such as air pressure and water level.  相似文献   

2.
On the basis of previous study results about the seismic anomaly precursor information quantity, universal and synthetic mathematical expressions that describe the precursor information quantity of various seismic anomalies are further given. Starting from large amounts of data of earthquake cases, the problem of the sustained effective time of seismic anomaly was studied again and the mathematical relationship between the sustained effective time of seismic anomaly and continuing effective time of seismic anomaly was further established. About one million pieces of precursor observation data belonging to 371 items of hydrochemistry, deformation, geomagnetism, stress, water level, geoelectricity, etc. In North China region in the period of 1980～ 1997 were collected and sorted out, and the seismic anomaly precursor information quantity of these items was calculated item by item. The evolutionary characteristics of seismic anomaly precursor information field in North China region in about 20 years and their relation to earthquakes were studied; an index system for medium- and short-term predictions of earthquakes with Ms ≥ 5.0 in North China region was established. After having checked by the R-value scoring method, the index system for synthetic earthquake prediction was proved to be of certain efficacy in medium- and short-term earthquake prediction.  相似文献   

3.
The contrast research results show that the number of items and stations with imminent, short and medium term precursor anomalies for the Wenchuan M_S 8. 0 earthquake is less than that of the Menglian earthquake. The number of anomalies and stations associated with the Wenchuan earthquake increased in the early stage of the short-term range,as opposed to the later period for the Menglian and Lijiang earthquakes. Most of the medium term anomalies occurred two to three years before the Wenchuan earthquake,when the number of anomaly stations and items was eleven,and a great change appeared in the observation values in about half of the stations ( items ) . However,for the Menglian earthquake,medium term anomalies happened one to two years before the earthquake, the number of abnormal stations and items reached 20,and a sharp change appeared in the observation values six months to one year before the earthquake in about 30 percent of the stations or items. In the epicenter and the nearby area,the macroscopic abnormalities started 3 years before the Wenchuan earthquake and lasted intermittently until 1 month before the earthquake. Within 2 percent of the total area of the province,the macroscopic abnormalities accounted for 30 to 50 percent of the total number of anomalies of the Province. For the Xingtai,Tangshan,Haicheng,Songpan earthquakes,the macroscopic anomalies started two to three months before,or on the very day of the earthquakes. The common feature of the precursors between the Wenchuan and other strong earthquakes is the appearance of tremendous changes in a certain number of observation values of anomalies in the mid and short terms before all these earthquakes.  相似文献   

4.
Abnormal disturbances, s uch as sharp pulses, w ere observed by vertical pendulum tiltmeters in Wudu, Hanzhong and Ningshaan seismic stations on August 6, 2008.According to the time and spatial location of the anomalies,we build a"source precursor"propagator to calculate possible focal region by aid of quasi-Newton least squares and grid search methods. The calculated focal region is located at the aftershock area of the Wenchuan earthquake on the northern section of Longmenshan fault zone,which may be related to the 54km-away M S5. 0 Pingwu-Beichuan earthquake,with starting time of about thirty three hours before the earthquake.  相似文献   

5.
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   

6.
In this paper, the precursor response characteristics of digital fluid caused by the Wenchuan M8.0 and Yushu M7.1 earthquakes are studied, and the response difference of the observations of Wuliying well to the two strong earthquakes is compared. The result shows that the abnormal fluid response has a certain relationship with earthquake size and epicenter distance. The greater the earthquake, and the closer it is to the epicenter from the observatory, the more sensitive the response will be to fluid anomalies. Abnormal Helium release was first observed before both strong earthquakes in the fluid precursor observation. The release intensity is related to earthquake magnitude; the larger the magnitude, the stronger the abnormal changes. The large change in He release in a short period after the Wenchuan earthquake may be related to the continuous activity of strong aftershocks and the structural adjustment after the earthquake. Helium release increased significantly after both earthquakes, as contributed by the abnormal deep-sited Helium release. However, this process may be connected to the annual change from July to September or the hot-reservoir type gas release in the Wuliying well. In the earthquake preparation process, a large number of deep-derived Helium is released into the geothermal system and the entire composition is changed. Temporally, this gas release appears later than fault-type gas release, and the disappearance time of this anomaly is also much later. The response difference of the fluid precursor to the two strong earthquakes may be related to differences of deep structural setting and dynamic mechanism. It also shows there is a stronger correlation between Wenchuan M8.0 earthquake in the North-South Seismic Belt and North China region than the Yushu M7.1 earthquake in the internal Qinghai-Tibetan plateau. Helium gas can be a sensitive indicator for monitoring abnormal deep-gas activity of the region where the observation station is located. Hence, observation and research should be strengthened in the future.  相似文献   

7.
In this paper,the theory for applying remote sensing to earthquake prediction has been elucidated and an experiment has been made.Through the experiment,it has been found that the characteristics and temperature of infrared radiant of rocks vary as a function of rock stress,the order of magnitude of radiance variation is 10-5(W/cm2 sr um),the amount of variation of the radiant temperature is 0.2℃~0.8℃ and some significant precursor information has been discovered.The experiment has verified preliminarily that the advanced technology of remote sensing can be applied to earthquake prediction.  相似文献   

8.
The authors studied the seismic activity, precursory anomalies and abnormal animal behavior before the April 14, 2010 MS7.1 Yushu earthquake. Analysis showed that anomalies were not rich before the MS7.1 Yushu earthquake, but prominent anomalies were observed, such as the long and mid-term trend anomaly characterized by the seismic quiescence of MS6.0, MS5.0 and MS4.0 earthquakes, and the anomalies in precursor observation of surface water temperature in Yushu and Delingha and electromagnetic measurement in Pingan. There were a large number of animal behavior anomalies appearing one week before the earthquake. An M4.7 earthquake occurred 130 minutes before the main shock. In this paper, we studied the dynamic process of the Yushu earthquake preparation using the earthquake focal mechanism solutions on the Bayan Har block boundary since 1996. The results show that the Kalakunlun M7.1 earthquake in 1996, the Mani M7.5 earthquake and the Yushu MS7.1 earthquake have the same dynamic process. Long and mid-term trend anomalies may be related to the dynamics of evolution of different earthquakes. This paper also discusses the recurrence interval of strong earthquakes, foreshock identification and precursor observation of the Yushu MS7.1 earthquake.  相似文献   

9.
In order to study the spatiotemporal evolution of the precursory anomalies 10 years before the Wenchuan M_S8. 0 earthquake in 2008, the epicentral distance of the precursory anomalies is calculated by using the geometric center of the rupture region and the elliptical centerline of the aftershock region. The result shows, precursor anomalies gradually increased about 2 years before the Wenchuan earthquake. The ratio of abnormal items is greater than 25% in the near source area (about twice the source scale) and 17%-24% in the remote area (about 3-5 times the source scale). There are three different stages of spatiotemporal evolution of precursory anomalies. During the α stage (including α_1 and α_2,between 700 to 3000 days before the main earthquake),the anomalies are mainly distributed in the southwest and northwest area of the Wenchuan aftershocks area. It is shown that the precursors of the far source region and the near source area have the characteristics of outward expansion. During the β stage (between 300 to 700 days before the main earthquake), the anomalies are distributed in the southwest and northern region of the aftershock region, showing a large range of anomalies. During the γ stage (including γ_1 and γ_2, 300 days before the main earthquake),the range of anomaly distribution is wide,and the anomalies are distributed in the southwest and northeast of the aftershock area. The anomalies converged to epicenter (γ_1) in the far source region and expand outwards (γ_2) in the near source region. Results of the experimental study and mechanical analysis of earthquake preparation process indicate that the three-stage characteristics of precursory anomalies in the process of earthquake preparation may be controlled by the seismogenic body,which is a form of expression in the process of earthquake preparation and a universal featureduring the earthquake preparation process,which has a certain guiding role in earthquake prediction.  相似文献   

10.
The temporal and spatial variations of surface latent heat flux （SLHF） and diagnostic air temperature at 2m before and after the Ms5.7 earthquake occurring on November 26, 2005 in the area between Ruichang City and Jiujiang City, Jiangxi Province are summarized in this paper. It is found that before the earthquake significant SLHF anomalies and air temperature anomalies occurred in the epicentral area and its vicinity. The air temperature anomalies appeared from the 2nd to the 13th of November, 2005 and were concentrated at the epicentral area and in its southern part. Then two days later, that is, from the 4th to the 15th of November 2005, significant SLHF anomalies occurred in the epicentral area and to its northern area where many lakes are distributed along the active faults. During the anomalous period, the SLHF and air temperature at 2m exceeded the sum of average daily value over 26 years and 1.5 times of its mean square deviation. Both anomalies had maintained for 12 days with a peculiar distribution related to the tectonic active zone. It is considered that both of air temperature anomalies and SLHF anomalies are correlated to the movement of thermal flux from underground prior to earthquake. SLHF anomalies occurred over wide regions covered with abundant water, whereas air temperature anomalies occurred over land.  相似文献   

11.
汶川地震中云南地区地下流体典型前兆异常   总被引：1，自引：1，他引：0  
分析云南地区数字化和模拟前兆观测资料,确认滇东北及邻区水富水位、渔洞水位、曲靖地温及丽江地温等流体典型异常,与汶川8.0级地震的孕育及发生有关。分析认为:①汶川地震的典型流体异常与云南强震异常具有相似性;②汶川地震孕育与发生影响的区域性与多样性;③水温中期异常和数字化分钟值异常是值得关注的新异常现象。  相似文献   

12.
2008年汶川地震导致了大量地下含碳气体释放. 本文基于卫星高光谱数据采用差值法获取了汶川地震前后川西地区含碳气体异常的时空分布特征. 结果显示汶川地震前后不同含碳气体异常的时空分布特征不同. 空间分布上,CH4,CO2和CO异常分布于震中附近且受断裂控制明显,与热红外异常特征类似;CO和CO2异常的范围较CH4大,CO除沿断裂带分布外,在四川盆地也大面积出现. 异常出现时间上,CO2异常最早,其次为CH4和CO. 气体来源上,CO2和CH4主要来源于地球内部沿断裂带释放,在地球内部还原条件下,CH4还可由CO2还原形成;CO异常除了沿断裂带释放和由断裂带释放的CH4氧化生成外,还由四川盆地渗漏的CH4氧化生成. 本文结果可用于地震监测预测研究,不仅提供了新的地震前兆观测参数,还为地震热红外异常机制“地球放气温室效应”提供了科学依据,同时对地震引起的地质碳排放研究也有重要意义.   相似文献   

13.
区分"源兆"与"场兆",系地震预测探索中的重要课题。根据云南4组6级以上地震的地下流体前兆异常资料,系统分析了强震源兆的流体前兆异常特征。结果表明,在6级多强震的源兆区,即震中距100 km范围内,异常项目计有水位、水温、水氡、水汞及气汞;以中期、短期异常为主,临震异常很少;源兆异常台站和台项的比例均高于场兆。这些流体源兆特征的认识,可为利用流体异常判断地震危险区提供一定依据。  相似文献   

14.
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   

15.
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   

16.
介绍了在利用气象卫星热红外异常作地震短临预测的探索中，如何开发已有的气象卫星资料分析处理系统来捕捉、确定和提取地震前兆异常，分析震兆异常时空演变规律，计算地震“三要素”指标，建立地震预测思路。  相似文献   

17.
本文较为系统地分析了青海省玉树与德令哈二口地热观测井自2007年以来的水温观测数据,发现这两口井对2008年5月12日四川汶川MS8.0级和2010年4月14日青海玉树MS7.1级地震前均有较明显的前兆异常,此外某些强地震前也有类似的异常信息.进一步对每口井的水温异常信息(诸如异常幅度、持续时间)进行了定量分析,以及每口井对应不同地震的异常曲线形态对比、异常数据的相关性分析,得出这两口井在不同地震前的水温异常形态表现出高度相似性;通过对这些曲线形态的认识与分析,为今后利用水温数据进行经验预报地震的探索开辟一条新路径.另外得出玉树井水温异常的幅度随震级与震中距的不同呈规律性变化,具体表现在震级越大、井震距越小,对应的异常幅度越大、异常持续时间也越长,且玉树井的异常主要是中长周期的异常,这种特性对利用水温异常特征判断未来地震的强度有重要意义;德令哈井则呈现出短临异常特性十分明显的特点,这种特性对利用该井水温数据来判断发震时间有着重要意义.  相似文献   

18.
There are thermal infrared anomalies(TIA)before earthquake, and TIA has become one of the important parameters for assessing regional earthquake risk. However, not all of the surface infrared anomalies are related to tectonic activities or earthquakes. How to eliminate the influence of non-structural factors and extract the weak signals from strong disturbances is the key and difficult point for tectonic activities studies based on the thermal infrared remote sensing techniques. Land surface temperature(LST)background field is the basis for thermal infrared anomalies extraction. However, the established background fields in previous researches cannot eliminate the influence of climate changes, so the accuracy of thermal anomaly extraction is limited. Now an improved method is proposed. Combined with the periodic character of LST time series, harmonic analysis is lead into the process of LST background field establishment. Specifically, the yearly trend of LST is fitted based on Fourier Approximation method. As a new background field, the yearly trend is dynamic, includes the local and the yearly information. Then, based on the rule of "kσ", the earthquake anomalies, calculated by RST with the yearly trend of LST, can be extracted. At last, the effectiveness of the algorithm can be tested by the quantitative analysis of anomalies with anomaly area statistics, anomaly intensity statistics and distance index statistics. The Wenchuan earthquake was discussed again based on the proposed algorithm with MODIS land temperature products in 2008. The results show that, there were obvious pre-earthquake thermal anomalies along the Longmen Mountains faults with a longer time; but there were no anomalies when the earthquake happened; and the post-earthquake thermal anomalies occurred with much smaller amplitudes and scopes. Compared with the results derived from the traditional RST which is based on the spatial average of LST values, the TIA extracted by the new RST, which is based on the yearly trend of LST, is more fit with the active faults, and the process of the anomalies occurring and removing can be described in more detail. Therefore, as the background field to extract earthquake anomalies, the yearly trend of LST is more reliable.  相似文献   

19.
地震地下流体在地震预测研究与震情跟踪中发挥着重要作用.本文基于中国地震地下流体前兆观测台网所涉及的资料范围，系统收集了2008年四川汶川8.0级地震的可能地下流体前兆异常，分析了这些异常的空间展布、时空演化以及形态等总体变化特征.结果表明，收集到的68项异常均位于10-8应变量范围内，59项异常位于汶川8.0级地震3倍破裂区（约900 km）范围内，占异常总数的87%，这与国内外已发表的地下流体前兆异常空间分布范围和震级之间的关系相符，说明汶川8.0级巨大地震的前兆观测范围至少包含该地震3倍破裂尺度甚至更大；异常出现时间总体呈现出临近地震异常数量增多的特点，但异常数量并非逐渐增多，而是在震前5个月和1个月突然增多；异常形态特征复杂，水氡和水位总体呈现出趋势性异常特征，水温总体表现出短临变化特征，主要表现为震前1—3个月突升、突降或波动异常变化.此外，本文还结合国内外已发表的地震地下流体前兆异常以及地震孕育理论，讨论了异常的空间分布、时间尺度与未来震中的关系，这对深入认识地下流体前兆异常及产生机理都具有重要的现实意义和科学价值.  相似文献   

20.
2009年新疆柯坪块体3次5级地震前异常分析   总被引：1，自引：0，他引：1  
研究2009年柯坪块体3次5级地震前的地震活动和前兆观测结果表明:3次5级地震前,柯坪块体存在5级地震平静的长期异常,4级地震多次平静、增强交替活动的中期异常,小震集中活动的短期异常;地震发生的短临阶段,震中附近的阿合奇地震台地倾斜、乌什地震台水管倾斜仪及地磁、地电和巴楚地应力存在不同程度的短临异常。参考汶川地震,有关专家对地震预报和震前异常的新思考和新认识,结合3次5级地震的类型和错断方式,分析震前小震活动和前兆异常,并对震前地震活动和前兆异常进行了综合分析和探讨。  相似文献   

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