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Load-Unload Response Ratio and Accelerating Moment/Energy Release Critical Region Scaling and Earthquake Prediction 总被引：20，自引：0，他引：20
X. C. Yin P. Mora K. Peng Y. C. Wang D. Weatherley 《Pure and Applied Geophysics》2002,159(10):2511-2523
-- The main idea of the Load-Unload Response Ratio (LURR) is that when a system is stable, its response to loading corresponds to its response to unloading, whereas when the system is approaching an unstable state, the response to loading and unloading becomes quite different. High LURR values and observations of Accelerating Moment/Energy Release (AMR/AER) prior to large earthquakes have led different research groups to suggest intermediate-term earthquake prediction is possible and imply that the LURR and AMR/AER observations may have a similar physical origin. To study this possibility, we conducted a retrospective examination of several Australian and Chinese earthquakes with magnitudes ranging from 5.0 to 7.9, including Australia's deadly Newcastle earthquake and the devastating Tangshan earthquake. Both LURR values and best-fit power-law time-to-failure functions were computed using data within a range of distances from the epicenter. Like the best-fit power-law fits in AMR/AER, the LURR value was optimal using data within a certain epicentral distance implying a critical region for LURR. Furthermore, LURR critical region size scales with mainshock magnitude and is similar to the AMR/AER critical region size. These results suggest a common physical origin for both the AMR/AER and LURR observations. Further research may provide clues that yield an understanding of this mechanism and help lead to a solid foundation for intermediate-term earthquake prediction. 相似文献
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地震临界区域尺度的界定对于地震前兆研究有着重要意义。通过加卸载响应比(LURR)及震前矩张量加速释放(AMR)两种模型对地震临界区域尺度进行了分析。采用不同半径区域内地震事件的Benioff应变分别计算LURR和AMR时间序列,震前引起时间序列异常变化最明显的半径尺度所定义的区域就是最佳地震临界区域。华北地区M>5震例研究结果显示两种模型所得到的最佳地震临界区域具有明显的一致性,最佳临界区域半径与主震震级之间统计的线性关系斜率约为0.34～0.36。研究结果表明通过不同预测模型可以较为定量的评价地震临界区域尺度,从而为地震预测研究提供依据。 相似文献
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This paper discussed the random distribution of the loading and unloading response ratio(LURR) of different definitions(Y_1～Y_5)using the assumptions that the earthquakes occurfollowing the Poisson process and their magnitudes obey the Gutenberg-Richter law.Theresults show that Y_1～Y_5 are quite stable or concentrated when the expected number of eventsin the calculation time window is relatively large(>40);but when this occurrence ratebecomes very small,Y_2～Y_5 become quite variable or unstable.That is to say,a high value ofthe LURR can be produced not only from seismicity before a large earthquake,but also from arandom sequence of earthquakes that obeys a Poisson process when the expected number ofevents in the window is too small.To check the influence of randomness in the catalogue tothe LURR,the random distribution of the LURR under Poisson models has been calculated bysimulation.90%,95% and 99% confidence ranges of Y_1 and Y_3 are given in this paper,which is helpful to quantify the random influe 相似文献
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Statistical Tests of Load-Unload Response Ratio Signals by Lattice Solid Model: Implication to Tidal Triggering and Earthquake Prediction 总被引：1，自引：0，他引：1
— Statistical tests of Load-Unload Response Ratio (LURR) signals are carried in order to verify statistical robustness of the previous studies using the Lattice Solid Model (Mora et al., 2002b). In each case 24 groups of samples with the same macroscopic parameters (tidal perturbation amplitude A, period T and tectonic loading rate k) but different particle arrangements are employed. Results of uni-axial compression experiments show that before the normalized time of catastrophic failure, the ensemble average LURR value rises significantly, in agreement with the observations of high LURR prior to the large earthquakes. In shearing tests, two parameters are found to control the correlation between earthquake occurrence and tidal stress. One is, A/(k T) controlling the phase shift between the peak seismicity rate and the peak amplitude of the perturbation stress. With an increase of this parameter, the phase shift is found to decrease. Another parameter, A T/k, controls the height of the probability density function (Pdf) of modeled seismicity. As this parameter increases, the Pdf becomes sharper and narrower, indicating a strong triggering. Statistical studies of LURR signals in shearing tests also suggest that except in strong triggering cases, where LURR cannot be calculated due to poor data in unloading cycles, the larger events are more likely to occur in higher LURR periods than the smaller ones, supporting the LURR hypothesis. 相似文献
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加卸载响应比（LURR）方法是通过固体潮加卸载过程中的某一物理参数的响应差异探查区域应力场演化。本文将这一方法应用于2019年6月17日四川长宁MS6.0地震,根据LURR时序演化探查震源区介质的应力状态变化,提取可能的震前异常信息。首先采用贝尼奥夫应变作为响应量计算LURR,通过固体潮在地震断层面的最优滑动方向上引起的库仑破坏应力变化来判断加载还是卸载,结果显示LURR值自2018年年初开始快速增加并在2018年年中达到峰值,此后异常持续至地震。在此基础上对该地区的大地形变和地下井水位资料进行了LURR分析,发现水富水平摆倾斜仪的东西和南北分量在LURR出现异常的同期发生明显偏转,而地震周边的地下井水位高值变化过程与长宁地震也有较好的对应关系。研究表明在长宁地震发生前,存在地震活动和地下水位的LURR异常,且异常时间与水富倾斜同步,暗示震源区介质存在明显的应力积累过程。 相似文献
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加卸载响应比是一种中短期地震预测方法.按照该方法,通常在大地震发生之前加卸载响应比时间序列会出现明显的异常高值.早先的研究发现,震前临界区域的选择对加卸载响应比的计算有很大影响.我们发展了一种使用震前应力积累区域取代传统圆形区域计算加卸载响应比的算法,提高了加卸载响应比的地震预测能力,其震前库仑应力场分布采用地震断层位错模型将同震滑移量反向滑移的方法计算.美国南加州近20年来发生的4次M6.5地震以及2008年中国汶川MS8.0地震的研究事实表明,使用库仑应力算法得到的加卸载响应比时间序列,前兆变化相对于圆形区域算法更为明显,且对目标地震的位置、震级预测更为明确.库仑应力算法的这一独特性质,使我们可以针对不同地区的活动构造特征对未来地震发生的地点和大小提供信息和约束. 相似文献
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LURR's Twenty Years and its Perspective 总被引：4，自引：0，他引：4
Xiang-Chu Yin Lang-Ping Zhang Hui-Hui Zhang Can Yin Yucang Wang Yongxian Zhang Keyin Peng Haitao Wang Zhiping Song Huaizhong Yu Jiancang Zhuang 《Pure and Applied Geophysics》2006,163(11-12):2317-2341
Seismogenic process is a nonlinear and irreversible one, so that the response to loading of a seismogenic zone is different from the unloading one. This difference reflects quantitatively the process of an earthquake preparation. A physics-based new parameter-Load/Unload Response Ratio (LURR) was proposed to measure quantitatively the proximity to a strong earthquake and then used to be an earthquake predictor. In the present paper, a brief history of LURR is recalled; inspection of real earthquake cases, numerical simulations and laboratory studies of LURR, prediction efforts in terms of LURR, probability problem of LURR and its prospect are also expatiated. 相似文献
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加卸载响应比是一种刻画震源区介质损伤程度的物理学参数,它通过随时间的变化来反映地震孕育的过程来进行地震预测。通过对1990—1999年新疆地区部分中强地震前加卸载响应比时空演化特征进行分析,并基于该理论得到孕震积分的概念应用于震例中。结果表明:中强震震前在震中附近可能存在多个高加卸载响应比值区,它们大致围成椭圆状或环状,地震通常发生在异常高值波动或减弱的过程中;异常峰值至发震时间比理论时间要短,这可能表明新疆地区构造活动剧烈,孕震周期较短。 相似文献
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加卸载响应比理论已在地震预测中得到广泛应用，但也面临挑战。本对加卸载响应比理论及方法进行了分析，并提出该理论几个可能的研究方面：(1)根据固体潮应力变化值给定每个小地震Benio盯应变在加卸载响应比计算中的权重；(2)考虑地震之前应力空间分布，确定加卸载响应比可能升高的区域形状，进而确定加卸载响应比计算中小震资料的选取范围；(3)将实测的小震震源机制与假定小震震源机制都相同时的加卸载响应比计算结果进行比较，研究测定的小震震源机制对加卸载响应比方法的改善情况；(4)研究加卸载响应比方法对不同震源机制类型地震的适用情况。 相似文献
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为了探索地震预报的新途径，本文分析了各种现有主要地震前兆。尽管它们在地震预报工作中曾经起过并且今后还将继续起着重要作用，但是，这些前兆与地震的发生都不存在唯一性的对应关系。这表明，到目前为止，还没有找出这些地震前兆和地震孕育过程之间真正内在的本质联系。本文从震源介质的固有特征及非线性系统不稳定性问题的本质出发，借鉴经典力学中的量纲分析与现代信息论的概念，提出了一个表征孕震系统不稳定性逼近程度的新的无量纲参数Ｙ，称之为ＬＵＲＲ（加载／卸载响应比）。ＬＵＲＲ定义为式中，Ｘ＋和Ｘ－分别是孕震系统在加载和卸载时的响应率。 相似文献
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Huai-zhong Yu Jia Cheng Xiao-tao Zhang Lang-ping Zhang Jie Liu Yong-xian Zhang 《Pure and Applied Geophysics》2013,170(1-2):173-183
Prior to an earthquake, natural seismicity is correlated across multiple spatial and temporal scales. Many studies have indicated that an earthquake is hard to accurately predict by a single time-dependent precursory method. In this study, we attempt to combine four earthquake prediction methods, i.e. the Pattern Informatics (PI), Load/Unload Response Ratio (LURR), State Vector (SV), and Accelerating Moment Release (AMR) to estimate future earthquake potential. The PI technique is founded on the premise that the change in the seismicity rate is a proxy for the change in the underlying stress. We first use the PI method to quantify localized changes surrounding the epicenters of large earthquakes to objectively quantify the anomalous areas (hot spots) of the upcoming events. Next, we delineate the seismic hazard regions by integrating with regional active fault zones and small earthquake activities. Then, we further evaluate the earthquake potential in the seismic hazard regions using the LURR, SV and AMR methods. Retrospective tests of this new approach on the large earthquakes (M > 6.5) which have occurred in western China over the last 3 years show that the LURR and SV time series usually climb to an anomalously high peak months to years prior to occurrence of a large earthquake. And, the asymptote time, t c, “predicted” by the AMR method correspond to the time of the actual events. The results may suggest that the multi-methods combined approach can be a useful tool to provide stronger constraints on forecasts of the time and location of future large events. 相似文献
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2012年天津地区三次地震前水位对固体潮振幅响应计算分析 总被引：2，自引：0，他引：2
2012年在天津及其周边地区发生了唐山4.8级, 宝坻4.0级和宝坻3.5级三次地震。 本文收集整理了天津地区固体潮反映较好的宝坻井、 王3井、 高村井以及张道口井2012年的水位观测数据和气压数据。 采用卷积回归和多项式拟合方法, 对水位观测数据进行气压效应及趋势项的去除, 并对水位数据进行数字滤波处理, 增强水位固体潮信号。 在对数据进行以上有效预处理后, 采用类似于Nakai拟合模型, 以每两天数据为一组, 分别对不同窗口长度滤波处理后的水位数据进行体应变固体潮响应振幅因子比的计算。 计算结果表明, 三次地震前比值均出现明显高值变化。 经比较当窗长选取96 h和120 h进行滤波时计算效果最为明显, 其异常成组出现, 并且变化幅度较大。 由以上这四口井水位对固体潮响应振幅因子比在三次地震发生前后的变化分析, 地震前由于应力的积累, 比值会出现高值变化, 小震活动对应力的积累具有缓解释放作用, 并且结合地震活动以及震源机制解可以对应力的积累-释放过程有一定的了解与印证。 相似文献
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加卸载响应比(LURR)的基本思路是希望能够通过刻画震源区介质的损伤程度,反映地震孕育的进程,从而预测地震.近30年来,很多人对加卸载响应比做了大量基础研究,取得了一系列新的进展.加卸载响应比在地震预测实践中也取得了一定的效果,异常区与地震发生的位置有较好的对应性,但是预测效果仍不够理想.究其原因主要是:在实际预测中对当地的地球物理情况考虑的不够.本文采用量纲分析与加卸载响应比结合的方法,综合考虑当地的地球物理情况,例如剪应变率和平均地震波能量等因素的影响.文中选取1970年以来发生在中国大陆的34个震例资料,通过分析得到了与发震震级和时间相关的无量纲量π1和π3,根据对实际数据的拟合,π1和π3均与震级成指数关系.在应用于地震预测实践时,首先根据LURR空间扫描结果选取异常区,然后确定异常区的地球物理参数,通过π1确定震级M,再由π3确定发震时间T. 相似文献
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The Load/Unload Response Ratio (LURR) method is proposed for prediction of the failure of brittle heterogeneous materials. Application of the method typically involves evaluating the external load on materials or structures, differentiating between loading and unloading periods, determining the failure response during both periods from data input, and calculating the ratio between the two response rates. According to the method, the LURR time series usually climbs to an anomalously high peak prior to the macro-fracture. To show the validity of the approach in engineering practice, we applied it to the loading and unloading experimental data associated with a two-floor concrete-brick structure. Results show that the LURR time series of the two floors consists of the damage evolution of the structure: they are at low level for most of the time, and reach the maxima prior to the final fracture. We then attempt to combine the LURR values with damage variable (D) to provide the health assessment of the structure. The relationship between LURR and D, defined as a function of Weibull stochastic distribution, is set up to provide more detailed underlying physical means to study damage evolution of the structure. The fact that the damage evolution of the structure correlates well with the variation of LURR time series may suggest that the LURR approach can be severed as a useful tool to provide the health assessment to big scale structures or ancient buildings. 相似文献
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多年的实测数据表明,大桥水库的坝前水位年变化约40m,库水对库盆的静压变化大约为4×105Pa,比固体潮的作用大2个量级,水库的蓄水和放水是对库区影响最大的加卸载力源。根据加卸载响应比理论(LURR),用库区的地震频次和能量分别研究在大桥水库诱发M_S4.6地震前后加卸载响应比的变化。结果表明:在大桥水库及附近相对较大的范围和水体附近相对较小的范围内,当库水加载过程中发生小震群时,地震频次加卸载响应比Y_n和C_r值显示高值异常,表明研究区岩石处于临近破裂状态,其后发生4.6级水库诱发地震;蓄水前后地震频次库水加卸载响应比Y_n和C_r值的平均值有明显差异;在大桥水库诱发的4.6级地震前,库水加卸载作用导致的地震频次及能量的加卸载响应比在震前存在明显的高值异常,震后异常消失。大桥4.6级震例表明库水加卸载响应比可有效应用于水库诱发地震的监测预报 相似文献
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The Load/Unload Response Ratio (LURR) method is a proposed technique to predict earthquakes that was first put forward by Yin (1987). LURR is based on the idea that when an area enters the damage regime, the rate of seismic activity during loading of the tidal cycle increases relative to the rate of seismic activity during unloading in the months to one year preceding a large earthquake. Since earth tides generally contribute the largest temporal variations in crustal stress, it seems plausible that earth tides would trigger earthquakes in areas that are close to failure (e.g., Vidale et al., 1998). However, the vast majority of studies have shown that earth tides do not trigger earthquakes (e.g., Vidale et al., 1998; Heaton, 1982; Rydelek et al., 1992). In this study, we conduct an independent test of the LURR method, since there would be important scientific and social implications if it were proven to be a robust method of earthquake prediction. Smith and Sammis (2004) undertook a similar study and found no evidence that there was predictive significance to the LURR method. We have repeated calculations of LURR for the Northridge earthquake in California, following both the parameters of X.C. Yin (personal communication) and the somewhat different ones of Smith and Sammis (2004). Though we have followed both sets of parameters closely, we have been unable to reproduce either set of results. Our examinations have shown that the LURR method is very sensitive to certain parameters. Thus it seems likely that the discrepancies between our results and those of previous studies are due to unaccounted for differences in the calculation parameters. A general agreement was made at the 2004 ACES Workshop in China between research groups studying LURR to work cooperatively to resolve the differences in methods and results, and thus permit more definitive conclusions on the potential usefulness of the LURR method in earthquake prediction. 相似文献
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Revisiting the Tidal Activation of Seismicity with a Damage Mechanics and Friction Point of View 总被引：2，自引：0，他引：2
— The Load Unload Response Ratio theory (LURR) puts forward the idea that the ratio of seismicity during times of increased tidal loading to times of decreased tidal loading takes on anomalously large values as the preparatory region of the earthquake approaches a critical state. We repeated the calculations of LURR for several earthquakes in California, for which results had been published, using estimates of the parameters which could be determined from the published work. We were unable to confirm any LURR ratio predictive significance. We test an alternative method of evaluating the influence of tidal stresses on earthquakes based on damage mechanics. As in rock mechanics experiments, it may be that anomalous activation of seismicity prior to large earthquakes occurs only during those time intervals when the applied stress exceeds values previously attained. We applied this approach to analyze the same data set used to test the LURR hypothesis, and it also failed to reveal any significant precursory indications. It may be that time-dependent failure processes such as self-driven nucleation occur on a time scale longer than the diurnal tide, thus destroying the expected synchronization. 相似文献