江苏-南黄海地区中强地震的可公度性及其预测研究

根据信息预测理论分析,江苏一南黄海地区M≥6级强震具有显著的可公度性。在回顾总结1996年11月9日南黄海6.1级地震预测的基础上,对南黄海海域1846年以来6级强震可公度性的基本结构及其预测功能进行了深入研究,同时建立了可公度预测模型,对该区未来强震趋势进行预测探讨。结果表明,1999～2000年,该区有可能发生M≥5地震,2002年前后南黄海海域有可能再次发生M≥6级强震。     

四川M_S≥6.8级地震的时空对称性研究

20世纪以来,对地震的预测与分析希望能用人类的智慧减少地震灾害对人类的伤害,并取得了一些成果。选取四川M_S≥6.8级以上地震,利用时间对称法,通过三元、四元、五元可公度的计算,可公度结构系图和蝴蝶结构图的分析,结果显示,2016、2020年发生地震信号较强,通过经纬向迁移特征分析,大致判断下次地震发生在31.0°N以北,101.6°E以西地区。并分析地震的发生与太阳黑子的关系。该预测对下一次四川地震的防灾工作有一定的意义。     

祁连山—六盘山地震带MS≥5.1地震时空对称性研究

根据1954年以来祁连山—六盘山地震带的地震数据,通过三元、四元、五元可公度计算、蝴蝶结构图分析和可公度结构系分析,对该地区地震灾害的时间对称性进行了趋势判断。理论计算结果表明：祁连山—六盘山地震带在2015年和2016年这两个年份强震信号较强,有可能发生较大震级地震。根据空间对称性和强震震中经、纬向迁移特征分析,判断出下一次地震发生地点大致在36°~39°N,95°~101°E区域。本研究可丰富重大灾害趋势判断研究案例。     

基于可公度方法的伊朗地区地震活动趋势判断

地震活动趋势判断是一个十分复杂的难题,我们需要从多方面进行探索与研究.本文采用1900-2013年伊朗地区≥6.7级强震数据,对伊朗地区地震活动进行趋势判断.在可公度方法的基础上,利用蝴蝶结构图和可公度结构系进一步分析时间序列的对称性,再通过太阳黑子活动的周期对照,判断出2016a发生下一次强震的信号较强.利用震中空间区位的迁移研究发现其空间迁移经纬向具有对称性和同步的突变性,判断认为发生强震的位置在伊朗东部北纬34度左右地区,该趋势判断对可公度法的探索研究具有一定贡献意义.     

1971年以来土耳其强震时空特征研究

通过应用可公度法和蝴蝶结构法对土耳其地区M_S≥6.4强震进行了分析, 结果表明, 土耳其在2015年和2016年强震信号较强, 有可能发生较大震级地震. 其中2015年信号要强于2016年. 通过对称性和震中迁移分析发现土耳其地区强震的空间迁移具有规律性和对称性, 以每4 a为一周期存在东西方向的回旋迁移规律. 其纬向对称轴为38.8°N, 经向对称轴为37.4°E, 未来强震可能向东北方向迁移.      

美国阿拉斯加州M_S≥7地震的时空对称性与趋势判断

在时间对称性方面,利用可公度信息提取法和蝴蝶结构图对1970年来阿拉斯加州MS≥7强震进行分析,认为阿拉斯加州2015年发生强震的信号最强。通过对震中空间迁移分析,发现形成的三角形存在关于57°N纬线和150°W经线对称的规律;纬向上存在连续的2次震中位于57°N的北侧,另一次位于57°N南侧为主的迁移规律,经向上有连续的2次震中在150°W东侧,一次在150°W西侧为主的迁移规律。因此判断,未来强震可能向东北方向迁移。同时,由唯象到唯理,对可公度法的物理机理做了研究讨论,为今后国内地震趋势研究提供了参考。     

墨西哥M_W≥7.5地震时空对称性及趋势研究

在统计1900~2013年墨西哥MW≥7.5地震数据的基础上,运用可公度理论分别从时间和空间的角度进行地震灾害的趋势预测。利用蝴蝶结构图和可公度结构系加强对时间对称性的分析,再通过地震震中的经纬度迁移和空间迁移规律,判断得出,墨西哥2016年的灾害信号较强,有发生7.5级以上地震的可能。将地震的时空表像和对称性结合并分析其可能的机理,为地震灾害的趋势判断研究提供一定的参考。     

淮河流域洪涝灾害时间对称性研究

准确判断重大自然灾害发生趋势对于防灾减灾意义重大.基于时间对称性理论,本文构建“可公度降噪—对称性趋势判断—信息结构系稳定性检验”研究模式,判断了淮河流域(HRB)洪涝灾害发生趋势.结果表明:(1)通过可公度降噪处理去除了噪声元素,提高了预测的精确性;(2)运用三元可公度、蝴蝶结构图、信息结构系等方法判断,2019年HRB发生洪涝灾害的信号较强,该年发生洪涝灾害的随机性概率为66.7%,不漏报置信水平为57.1%;(3)通过洪涝灾害与太阳黑子活动的相关性分析可知,HRB在太阳黑子活动谷年附近易发生洪涝灾害,进一步提高了预测结果的可信度.“可公度降噪—对称性趋势判断—信息结构系稳定性检验”研究模式是对现有时间对称性方法的补充和完善,以期为中国灾害预测起到一定的推动作用.     

基于对称性的委内瑞拉及周边地区MW≥6.0地震趋势判断及与地球自转关系分析

在全球化的大背景下,重大自然灾害发生的频率不断加快,其危害对人们的生产生活造成了严重的威胁。地震灾害是重大自然灾害之一,发生的频率虽然不高,但造成的人员伤亡和经济损失十分巨大。对地震进行趋势判断,其理论和现实意义重大。文章运用三元、四元、五元可公度计算来预测委内瑞拉及周边地区近30多年M_W ≥ 6.0地震信号的强弱,利用蝴蝶结构图和可公度结构系加强对时间对称性的分析,再通过震源的经纬度迁移和空间迁移规律,本文创造性地分析了该地地震与地球自转加速度的关系。结果得出：（1）委内瑞拉及周边地区发生M_W ≥ 6.0地震的时间上在 2018年信号最强,2017和2019年较强。（2）空间上在10°N—11°N,63°W—65°W之间地震可能性最强。（3）委内瑞拉及其周边地区M_W ≥ 6.0地震与地球自转速度的转折变化有密切关系,未来可通过其变化规律帮助分析地震发生趋势。本文可为地震灾害的趋势判断研究提供一定的参考,为后续研究工作带来一些启示。     

菲律宾Ms≥7级地震活动规律及未来趋势

通过可公度信息提取方法、蝴蝶结构图、震中时空迁移特征分析近50年菲律宾Ms≥7级中、浅源地震,发现2013、2014年Ms≥7级地震信号强,2014年最强;22年地震主周期明显,其中可划出活跃期与平静期;2012年为菲律宾新地震周期及活跃期的开始;菲律宾Ms≥7级地震震中时空交替迁移规律明显,未来震中向西北部迁移.菲律宾Ms≥7级地震与太阳黑子活动22年双周期关系密切,多发生在太阳黑子活动偶数周期极大年附近及其下降段.目前,太阳黑子活动处于第24周期极大年附近,2013～2014年Ms≥7级地震发生的可能性很大,与可公度分析结果一致.     

ATTENUATION DES MULTIPLES EN SISMIQUE MARINE PAR ANTIMOYENNE*

A satisfactory attenuation of the multiples in marine seismic may be obtained by the application of the principle of “Antiaveraging”. This principle in a first step consists in getting the model of the organized noise, which one tries to eliminate by using an averaging method, and in a second step to subtract that model from the initial information. Obviously the elimination of the model should not simultaneously cause the elimination of useful signals. The model may be obtained if the considered organized noise keeps a constant shape or if its time-space deformation is known. Besides one has to assume the time-distance curve of the organized noise can be determined. Thus noise arrivals may be detected on the records. The “antiaveraging” is very often efficient when organized noises are stronger than signals or when a signal, once identified, exploited and then considered as an organized noise, can be attenuated in order to make the detection of the other signals easier.     

NEW FILTERING METHODS WITH “VIBROSEIS”*

In order to obtain high resolution correlograms, it is of importance amongst other things to get reflection signals with large bandwidth. An advantage of the VIBROSEIS *** *** Trade Mark and Service book of the Continental Oil Company.
method is that the frequencies radiated by the vibrators can be matched to the transmission response of the subsurface involved. By choosing the right frequency range, the highest possible amplitude and most favourable form may be given to the reflection signals. In a reflection correlogram, individual signals cannot be considered in isolation. Signals of different origin are interfering with one another. They very often have different amplitudes, so that it may be desirable in many cases to filter out events of certain apparent velocity. With the VIBROSEIS method this may be achieved quite simply. All frequencies of the noise signal are uniformly suppressed. The advantage is that noise signals, e.g. refraction signals, which cannot be sufficiently attenuated by wavelength filtering, may be completely eliminated by this velocity filtering without affecting the bandwith of the desired signal. The total dynamic range of the tape recording can be used for the registration of wanted events. To perform this kind of filtering several vibrators are necessary in the field; each of them is controlled by an individual signal. There is an unavoidable error of static and dynamic corrections which causes the results of reflection measurements to deteriorate when using multiple coverage. High frequency components especially are seriously affected by destructive interference. This difficulty can be avoided by using a VIBROSEIS signal with high frequency component amplitudes supported. For the probability of error of corrections a normal distribution is assumed. A smoothed amplitude characteristic may be achieved after stacking. The amplitude characteristic of seismic devices is commonly reduced to about 100 cps bandwidth. For further improvement of resolution of VIBROSEIS correlograms it is necessary to apply special filtering methods. This is of particular interest when any kind of gain control is used to display weak events more clearly. With increasing amplification the sidelobes of the strong signals may reach the size of the weak events. In order to eliminate this effect, the amplitude characteristic of the VIBROSEIS signal is adjusted for optimum suppression of side-lobes.     

NEW FILTERING METHODS WITH “VIBROSEIS”*

In order to obtain high resolution correlograms, it is of importance amongst other things to get reflection signals with large bandwidth. An advantage of the VIBROSEIS *** *** Trade Mark and Service book of the Continental Oil Company.
method is that the frequencies radiated by the vibrators can be matched to the transmission response of the subsurface involved. By choosing the right frequency range, the highest possible amplitude and most favourable form may be given to the reflection signals. In a reflection correlogram, individual signals cannot be considered in isolation. Signals of different origin are interfering with one another. They very often have different amplitudes, so that it may be desirable in many cases to filter out events of certain apparent velocity. With the VIBROSEIS method this may be achieved quite simply. All frequencies of the noise signal are uniformly suppressed. The advantage is that noise signals, e.g. refraction signals, which cannot be sufficiently attenuated by wavelength filtering, may be completely eliminated by this velocity filtering without affecting the bandwith of the desired signal. The total dynamic range of the tape recording can be used for the registration of wanted events. To perform this kind of filtering several vibrators are necessary in the field; each of them is controlled by an individual signal. There is an unavoidable error of static and dynamic corrections which causes the results of reflection measurements to deteriorate when using multiple coverage. High frequency components especially are seriously affected by destructive interference. This difficulty can be avoided by using a VIBROSEIS signal with high frequency component amplitudes supported. For the probability of error of corrections a normal distribution is assumed. A smoothed amplitude characteristic may be achieved after stacking. The amplitude characteristic of seismic devices is commonly reduced to about 100 cps bandwidth. For further improvement of resolution of VIBROSEIS correlograms it is necessary to apply special filtering methods. This is of particular interest when any kind of gain control is used to display weak events more clearly. With increasing amplification the sidelobes of the strong signals may reach the size of the weak events. In order to eliminate this effect, the amplitude characteristic of the VIBROSEIS signal is adjusted for optimum suppression of side-lobes.     

SUPERSTACK—AN ITERATIVE STACKING ALGORITHM*

An algorithm for separation of signals according to their coherency is proposed. The algorithm, called Superstack, is used on common depth point data after normal moveout corrections have been applied. The algorithm can be regarded as an iterative stacking procedure. After each stack, input values are changed depending on the consistency of the output of the previous stack. The Superstack algorithm is able to provide better separation of signals showing a different degree of horizontal consistency (coherency) than the normal horizontal stack. All noise signals in a CDP-gather may be assumed to show less horizontal consistency than the primary reflections. On this basis the algorithm will give an improved primary/multiple and an improved primary/noise ratio. The Superstack is very general, should not be especially expensive in terms of computer time, and can easily be implemented in routine processing.     

基于小波包变换的地震数据时频分析方法

介绍了瞬时频率的概念和瞬态谱的小波包计算方法,并结合时间域模拟信号给出了其时频分布,结果表明,小波包变换可准确技术地震信号的时变特征,值得推广应用。     

A possible UL Fseismice lectro-magnetic emission

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Design parameters for borehole strain instrumentation

The response of a borehole strain meter to hydrostatic and shear deformations in an isotropic medium is calculated to facilitate optimum instrument design and produce instrument response factors for parameters typically encountered in installed instruments. Results for an empty borehole are first compared with results for an instrument in intimate contact with the surrounding rock. The effects of the grout used to install the instrument are then examined. Where possible, analytic forms for the response factors are given. Results for typical installations are then presented in graphical form for optimizing instrument design in an environment of known elastic parameters. Alternatively, the results may be applied in the measurement of unknown strain signals, to correct for instrument response or to provide in-situ estimates of the elastic properties of the environment by examination of observed strain response to known strain signals.     

小波分析方法在提取井水位潮汐因子震前变化特征的初步应用

运用小波分析方法对1990年常熟、1995年苍山和1996年南黄海三个中强地震前江苏地区井水位固体潮的变化特征进行了研究，发现井水位M2波潮汐因子在地震前几个月几乎都出现一个幅度较大、周期为半月或一个月左右的异常信号，表明小波分析方法在处理和分析井水位潮汐资料方面可能是一种有效的方法。     

Magnetic field anomalies associated with geodynamic phenomena

Significant variations of the Earth's magnetic field seem to be associated with geodynamic phenomena, particularly volcanic cruptions and earthquakes. The variations have small amplitudes, generally only a few nT. These small signals are embedded into larger transient variations due to other natural or artificial causes. An original method of recovering interesting signals having amplitudes down to 1 nT, is to describe the whole variation analytically so that each component may be isolated. Several studies have shown that significant signals exist for tectonically active regions: 10–30 nT for large-scale arrays over periods of years; 5–15 nT for volcanic phenomena; 1–5 nT for earthquakes.Only a few test sites for volcanoes (New Zealand, Hawaii, Antilles) and earthquakes (essentially the San Andreas fault system) have been monitored so far.The cause of the type of magnetic variations studied here, which are associated with volcanism and rock failures, has most often been attributed to piezomagnetism. Some authors have suggested that electrokinetic effects associated with porosity-changes may also play a role.The isolated signals may, in the future, be used for hazard forecasting when the time-constants associated with the effects are known more precisely.     

利用固定台站分析长江激发气枪信号特征

“地学长江计划”安徽实验是以气枪震源为核心的大型主动源探测实验。通过在长江安徽段20个固定点定点激发气枪震源,结合109个固定台站、11条流动测线组成的观测网络,首次利用主动源实现了对长江流域安徽段约6万km2面积的三维地下结构探测。本文利用固定台站对长江激发气枪信号进行了分析,结果表明,长江中气枪信号激发效果良好,固定台记录中气枪信号可识别的最远距离达300km。对气枪信号绝对振幅的研究结果表明：① 50km处的气枪信号约为10nm量级,200km处的气枪信号小于1 nm;② 气枪信号强度的空间分布存在一定的方位各向异性,可能与长江的几何形状有关;③ 台站背景噪声对于提取气枪信号至关重要,高质量的固定台网为识别nm量级气枪信号提供了可能。