On the sensitivity of the lower ionosphere to a strong atmospheric energy action

Detailed investigations of the ionospheric and magnetospheric perturbations induced by earthquakes, volcanic eruptions and strong man-made actions such as explosions and special supersonic flights indicated that those phenomena can not be accounted for in the traditional framework of the acoustic-gravity mechanisms. A clue can be found in the particular sensitivity of the electrical conductivity of the D- layer to weak stochastic perturbations of electron concentration. The calculations show that the electron Pedersen conductivity, which is usually small in the homogeneous ionosphere, increases drastically because of ionospheric irregularities.Some refined effects in the Extremely Low Frequency (ELF) and Very Low Frequency (VLF) ranges can be predicted.     

Frictional discharge at fault asperities: Origin of fractal seismo-electromagnetic radiation

To investigate the relation between the rock friction and the fractal electromagnetic radiation before the main-shock of earthquakes, we conducted a friction experiment simulating the motion of an asperity on a fault plane, and observed photon emissions due to electric discharge by dielectric breakdown of ambient gases from friction contacts between rock minerals. This indicates that frictional discharges (plasma generations) could occur locally at microscopic asperities on fault surfaces. From concepts on the fractal size-distribution and temporal evolution of fault asperities, the frictional discharge occurring at asperities on the fault plane can be one of origins of the fractal electromagnetic radiation (Benioff electromagnetic radiation) prior to earthquakes.     

Monitoring ULF magnetic disturbances and schemes for recognizing earthquake precursors

Specific electromagnetic signals in the ULF range, which were observed in seismoactive regions prior to some strong and moderate earthquakes, are discussed with respect to the earthquake prediction problem. Characteristic features of such “seismogenic” ULF emissions are pointed out and compared with differential peculiarities of the ULF emissions of space origin. A new magnetometer technique for locating ULF emission sources is described. Methods are proposed for ULF data processing to investigate preparation activity within the earthquake source region, and to distinguish seismogenic signals from the background of space pulsations. Possible generation mechanisms of the ULF electromagnetic signals in seismic hazard systems are discussed.     

Satellite Thermal Infrared Earthquake Precursor to the Wenchuan Ms 8.0 Earthquake in Sichuan, China, and its Analysis on Geo-dynamics

Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band (10.3-11.3 μm) designed in China, the authors found that there existed obvious and isolated satellite thermal infrared anomalies before the 5.12 Wenchuan Ms 8.0 Earthquake. These anomalies had the following characteristics: (1) The precursor appeared rather early: on March 18, 2008, I.e., 55 days before the earthquake, thermal infrared anomalies began to occur; (2) The anomalies experienced quite many and complex evolutionary stages: the satellite thermal infrared anomalies might be divided into five stages, whose manifestations were somewhat different from each other. The existence of so many anomaly stages was probably observed for the first time in numerous cases of satellite thermal infrared research on earthquakes; (3) Each stage lasted quite a long time, with the longest one spanning 13 days; (4) An evident geothermal anomaly gradient was distributed along the Longmen seismic fracture zone, and such a phenomenon might also be discovered for the first time in satellite thermal infrared earthquake research. This discovery is therefore of great guiding and instructive significance in the study of the earthquake occurrence itself and the trend of the post-earthquake phenomena.     

Acoustic and electromagnetic emissions preceding the earthquake in Kamchatka

In 2013, simultaneous observations of acoustic and electromagnetic emissions ranging from 200 Hz to 11 kHz were carried out in Kamchatka; as a result, abnormal surges of the emissions were registered 1–2 days before seismic events with magnitudes M _LH ≥ 5 at a hypocentral distance up to 200 km. The most likely cause of the occurrence of the abnormal emissions in inherently different fields was activation of deformation processes preceding the earthquakes.     

汶川8.0级和仲巴6.8级地震中波红外热辐射异常

本文以静止卫星中波红外亮温为数据源,应用小波变换和计算功率谱方法对汶川8.0级地震和仲巴6.8级地震进行了分析研究。结果表明,这两次地震震前均出现了明显的短临热异常现象。这与长波辐射通量和热红外亮温资料的研究结果基本一致。在时间演化过程中热异常现象在震前存在一次明显的变化,这种变化有短临预测意义。地震前后热异常分布可能反映了区域应力集中和调整变化,根据异常的演化方向和异常消失区域可以估计发震的可能区域范围。     

Satellite Thermal Infrared Earthquake Precursor to the Wenchuan Ms 8.0 Earthquake in Sichuan,China, and its Analysis on Geo‐dynamics

Abstract: Based on an interpretation and study of the satellite remote-sensing images of FY-2C thermal infrared 1st wave band (10.3–11.3 μm) designed in China, the authors found that there existed obvious and isolated satellite thermal infrared anomalies before the 5.12 Wenchuan Ms 8.0 Earthquake. These anomalies had the following characteristics: (1) The precursor appeared rather early: on March 18, 2008, i.e., 55 days before the earthquake, thermal infrared anomalies began to occur; (2) The anomalies experienced quite many and complex evolutionary stages: the satellite thermal infrared anomalies might be divided into five stages, whose manifestations were somewhat different from each other. The existence of so many anomaly stages was probably observed for the first time in numerous cases of satellite thermal infrared research on earthquakes; (3) Each stage lasted quite a long time, with the longest one spanning 13 days; (4) An evident geothermal anomaly gradient was distributed along the Longmen seismic fracture zone, and such a phenomenon might also be discovered for the first time in satellite thermal infrared earthquake research. This discovery is therefore of great guiding and instructive significance in the study of the earthquake occurrence itself and the trend of the post-earthquake phenomena.     

Space observations of Transient Luminous Events and associated emissions in the upper atmosphere above thunderstorm areas

Sprites, jets and elves called Transient Luminous Events (TLE), observed in the middle and upper atmosphere above thunderstorms, are the manifestation of intense energy exchanges between the troposphere, stratosphere and mesosphere. Different types of luminous emissions have been identified by ground-based observations, showing the complexity of these phenomena. Space missions showed that transient emissions in the Earth atmosphere are very broad including Radio Frequency (RF), IR to FUV radiations and X-gamma ray emissions called Terrestrial Gamma Flashes (TGF) with energies reaching 30 Mev. However, there are no global observations of these events together. This paper reviews space observations performed up to now and emphasizes the challenges of the future space missions in global measurements of all possible emissions together for the understanding of the physical mechanisms at the origin of these phenomena and their effects on the Earth environment.     

岩石破裂过程中电磁辐射信号特征研究

为了探索震前电磁异常现象的物理机制,许多研究注重于分析岩石破裂过程中产生的电磁辐射信号。对花岗岩样品进行单轴加载,变形直至破裂,记录整个过程中产生的电磁辐射(EME)和声发射(AE)信号,对比分析。这里主要从两个方面分析岩石破裂过程中EME信号的特征:①利用非广延分析方法分析EME的能量分布情况,并与b值分析方法对比,推断岩石破裂类型以及裂纹发育过程;②利用统一等待时间定标律分析EME的时间特征,期望获得岩石破裂过程中EME信号等待时间的分布规律。结果表明,在拟合AE和EME信号的能量分布曲线时,发现b值只能拟合AE部分数据,完全不能拟合EME数据,而非广延参数q可以很好地拟合这两类信号。通过对比分析AE和EME信号的等待时间概率密度的分布情况,发现EME信号的集成效果相对较差,可能不满足统一等待时间定标律。     

Chlorophyll concentration and surface temperature changes associated with earthquakes

The preparation process of an impending earthquake may leave fingerprints on the earth??s surface. Elastic strain in rocks, formation of micro-cracks, gas releases and other chemical or physical activities in the earth??s crust before and during earthquakes has been reported to cause rises in temperature, surface latent heat flux (SLHF), upwelling index and chlorophyll-a (Chl-a) concentration on the ground or sea surface. Changes in surface temperature can be monitored with thermal infrared sensors such as NOAA-AVHRR and microwave radiometers like AMSR-E/Aqua. SLHF data and upwelling indices are provided by National Centers for Environmental Prediction (NCEP) Reanalysis Project and Pacific Fisheries Environmental Laboratory, respectively. This study examines behaviors of the above four factors prior to the past three oceanic and coastal earthquakes occurred at the Pacific Ocean (Northern California of June 15, 2005, Central California of September 28, 2004, and December 22, 2003). We were successful in detecting pre-earthquake anomalies prior to all three earthquakes. Our detailed analysis revealed 1?C5?°C rises in surface temperature in epicentral areas. Considerable anomalies in Chl-a concentration, 1?C2?weeks before the day of the main earthquakes, were spotted, which are attributed to the rise in upwelling index. Time series of SLHF showed meaningful rises from 1?month to a fortnight before the earthquake events. One problem in our research was the low resolution of the data which makes the graphs that are generated from NCEP database affected by all sources of anomalies, other than seismic activities, within an about 1.8°?C2.5° (200?km) area.     

基于LUCC和夜间灯光辐射数据的张掖市甘州区人口空间分布建模

尽管近年来统计数据的生成技术有了很大提高, 但可用的详细人口数据始终难以得到满足.在一些自然-人文要素耦合的建模研究中, 如生态经济集成建模、 环境和健康分析等都需要基于区域尺度的栅格人口分布建模方法.随着GIS和RS技术的发展, 上述建模方法已有较大进步.利用GIS技术, 基于夜间灯光辐射数据和LUCC在象元栅格水平上构建张掖市甘州区人口空间分布. 首先对DMSP夜间灯光辐射数据进行重采样, 通过普通克里金插值获得灯光数据; 然后与LUCC叠加分析, 利用回归分析的方法获取研究区土地利用、 灯光辐射指标和人口统计数据之间的定量关系, 完成空间化.并在乡镇尺度上进行模型检验, 模型总体的调整R²为0.88, 标准误差为400, 为下一步开展时空变化分析提供支持.     

Predicting failure in rocks and its implications for predicting earthquakes

In the laboratory rock failure can be predicted both in space and in time. The processes leading to failure are well understood and manifest themselves in measurable quantities. Ultrasonic velocity changes and surface strain anomalies are the most reliable indicators of the impeding failure. To a lesser degree and very much dependent on the deformation rate and the moisture content, acoustic emissions cluster in the vicinity of the failure shortly before the rupture occurs. The precursory failure zone has a linear dimension on the order of 1000 grain diameters. If the same physical mechanisms are involved in the Earth as failure is approached, then detailed velocity and surface strain measurements would greatly enhance our ability to predict earthquakes. With the realization of the Global Positioning System and a possible extension to a satellite holographic system, it is now possible to measure surface deformation inexpensively on a densely spaced grid.     

Satellite monitoring of anomalous effects in the ionosphere related to the great Wenchuan earthquake of May 12, 2008

In this paper, we present an investigation into plasma density disturbances and electric field perturbations associated with China, Sichuan, Wenchuan earthquake of magnitude M = 7.9 that occurred on May 12, 2008, at 06:28:01 UTC. The DEMETER (Detection of Electromagnetic Emissions Transmitted from Earthquake Regions) satellite was launched on June 29, 2004. The orbit of DEMETER is polar, circular with an altitude of 710 km and its main scientific objective is the study of ionospheric perturbations linked to seismic activity. For satellite orbits near the epicenter region, some ionospheric effects are investigated, which can be considered as possible earthquake precursors. The paper discusses anomalous effects in the ionosphere associated with the Wenchuan earthquake, which cannot be explained by factors of solar-magnetospheric origin. For satellite orbits eight to four days before the main shock, fluctuations in ion density and increase in horizontal and vertical components of electric field are observed near the epicenter. Post-effect is observed too. The observations suggest a coupling between the lithosphere-atmosphere-ionosphere and can be associated with the earthquake growing processes in the lithosphere and troposphere zones above the source. The results of ionospheric anomalous effects are presented and discussed. The results obtained are important because they are observed very near to epicenter.     

人工源超低频电磁波技术及在首都圈地区的测量研究

超低频 (SLF)电磁波技术利用地球物理和无线电物理相结合的原理 ,由人工产生大功率电磁波信号。在地面很大范围的许多测点同时测量该信号 ,可研究空间电磁场和地下电阻率结构 ,研究地震等引起的电磁场异常变化 ,探测地壳结构和地下资源。在首都圈地区的观测表明 ,SLF信号的功率谱密度超过天然场源信号数倍以上 ,所得到的视电阻率数据精度远高于天然源方法 ,并有长时间的稳定性。在测量期间距测点约 12 0km发生的迁安 4 .2级地震与观测的电磁场异常和视电阻率的变化有较好的对应性 ,并对产生这些变化的可能的成因机制进行了探讨 ,推测它们是区域应力场和震源区局部构造综合作用的结果。     

Sudden drop of fractal dimension of electromagnetic emissions recorded prior to significant earthquake

The variation of fractal dimension and entropy during a damage evolution process, especially approaching critical failure, has been recently investigated. A sudden drop of fractal dimension has been proposed as a quantitative indicator of damage localization or a likely precursor of an impending catastrophic failure. In this contribution, electromagnetic emissions recorded prior to significant earthquake are analysed to investigate whether they also present such sudden fractal dimension and entropy drops as the main catastrophic event is approaching. The pre-earthquake electromagnetic time series analysis results reveal a good agreement to the theoretically expected ones indicating that the critical fracture is approaching.     

Can electromagnetic disturbances related to the recent great earthquakes be detected by satellite magnetometers?

On December 26, 2004 the world's fourth largest earthquake since 1900 and the largest since the 1964 Prince William Sound, Alaska earthquake, occurred off the west coast of northern Sumatra with a magnitude of 9.3. On March 28, 2005 another event of magnitude 8.7 took place in the same region. The December 26, 2004 earthquake has prompted scientists to investigate possible electromagnetic signatures of this event, using ground magnetic observations. Iyemori et al. [Iyemori, T. et al., 2005. Geomagnetic pulsations caused by the Sumatra earthquake on December 26, 2004. Geophys. Res. Lett., 32, L20807, doi:10.1029/2005GL024083.] have suggested that a 3.6 min long geomagnetic pulsation, observed shortly after this event, was generated by the earthquake. They have speculated that a 30 s magnetic pulsation was also caused by the earthquake. Here for the first time, CHAMP satellite magnetic and electron density data are examined to find out if electromagnetic signatures which are possibly related to these recent megathrust earthquakes are observed in satellite magnetic data. We have shown that some specific features are observed after the two earthquakes, with periods of about 16 and 30 s. Our results favor an external source origin for the 30 s pulsation. Moreover, after more than 1 h, CHAMP magnetic data indicate the existence of a feature characterized by the same parameters (duration, amplitude, and frequency content), which could be associated with each earthquake, respectively. Further investigations are required in order to answer the question of whether these signals can be associated with earthquakes and to assign their possible usefulness with respect to earthquake development.     

广东省及邻区新生代以来构造运动与地震活动分区的研究

综合分析多年来地震地质调查资料,将广东省及部分邻区划分为具不同构造活动特点的6个区,分别论述、分析这些区内新生代以来的断裂构造、火山喷发、第四纪沉积及地震活动等。结果认为,由断层样品热释光测定确定的断层最近期活动年龄主要是在中更新世和晚更新世,沿海地带主要为晚更新世和全新世。新生代以来构造具继承性活动的地区是地震最活动地区,如琼雷地区。同时,由于历史上发生过强震,地震后至今具较大速率下沉地区,在今后相当长时间内可能是不易发生强震地区,如琼北东部和南澎-南澳地区;Ms6级地震将主要发生在晚更新世以来的新生盆地,如潮汕盆地和近岸海湾地区;Ms5级地震在一定条件下,几乎可能发生在省内的任何地区。     

Electro-magnetic earthquake bursts and critical rupture of peroxy bond networks in rocks

We propose a mechanism for the low frequency electromagnetic emissions and other electromagnetic and electric phenomena which have been associated with earthquakes. The mechanism combines the critical earthquake concept and the concept of crust acting as a charging electric battery under increasing stress. The electric charges are released by activation of dormant charge carriers in the oxygen anion sublattice, called peroxy bonds or positive hole pairs (PHP), where a PHP represents an O₃X/^OO YO₃ with X,Y = Si⁴⁺,Al³⁺,…, i.e. O⁻ in a matrix of O²⁻ of silicates. We propose that PHP are activated by plastic deformations during the slow cooperative build-up of stress and the increasingly correlated damage culminating in a large “critical” earthquake. Recent laboratory experiments indeed show that stressed rocks form electric batteries which can release their charge when a conducting path closes the equivalent electric circuit. We conjecture that the intermittent and erratic occurrences of EM signals are a consequence of the progressive build-up of the battery charges in the Earth crust and of their release when crack networks percolate through the stressed rock volumes, providing a conductive pathway for the battery currents to discharge. EM signals are thus expected close to the rupture, either slightly before or after, that is, when percolation is most favored. The proposed mechanism should be relevant for the broader understanding of fractoemissions.     

被动式超低频电磁探测数据采集与处理方法研究

由于被动式超低频电磁探测仪具有便携易用、野外布线简单、受地形影响小并且对低阻体、高阻体均有反映的特点,因此在能源勘探、资源勘察和地质构造探测中展现出良好的性能与开发潜力,接收来自地下深部的天然源超低频电磁信号的勘探技术,已成为国内外近些年来的研究热点。文中首先介绍了被动式超低频电磁探测技术最近几年的野外试验情况及超低频磁场传感器的主要技术指标水平,认为目前BD-6型被动式超低频电磁探测仪无论在频谱分辨率、信噪比,还是在探测效率方面都得到了极大提高;其次,分析了场源效应、频深转换公式、分辨率因素对数据采集、处理过程的影响;提出场源效应导致的随机噪声可以通过多次采集数据叠加平均方法加以降低,利用已知地质和钻井资料修正后的频深转换公式更适用于某种勘探目标(煤层气、地下水等)和某个地区探测数据的解释;采用适当的线性(谱分析法)和非线性(分数维法)分析方法,可以为探测数据的处理与解释提供新的方法和技术途径。     

断块大地构造与地震活动的构造物理研究

断块大地构造理论几乎涉及地震活动的各个方面： 1）地震记录表明不但是强震,大多数6级以上地震也分布在构造块体边界上,构造块体控制了地震分布; 2）地震活动规律体现在块体整体活动中。例如,鄂尔多斯地块周边单个断陷带的地震活跃期与平静期长短不一,无明显规律。但当把鄂尔多斯地块周边作为一个整体,其地震活动在时间上显示了准周期性; 3）地块运动通过周边断层交替活动实现。从断层活动相互作用的时间间隔和错动形式出发可把它分为强震交替活动型（又可分长时间间隔和短时间间隔两类）和强震与弱震或断层蠕动交替活动型。强震交替活动型中时间间隔很短的双震活动较早被发现。强震交替活动型中时间间隔很长的类型虽然不易识别,但是依赖于中国历史地震目录,还是发现鄂尔多斯地块周边山西断陷带与渭河断陷带在历史上的3次交替活动等; 强震与弱震或断层蠕动型的交替活动型很不容易被发现,仅在台网较密,观测条件较好的北京地区观测到。4）利用一些实验结果讨论了交替活动的规律。此外,结合断块大地构造理论对一些地震现象进行了讨论。