共查询到18条相似文献，搜索用时 234 毫秒
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态矢量是一种中短期地震预测方法,通常在大地震发生之前,态矢量时间序列会发生明显的异常变化.在此基础上,进一步尝试根据震前应力场分布,提高态矢量的地震临界敏感性,震前库仑应力分布采用地震断层位错模型将滑移量反向滑移的方法计算,2008年汶川地震震前的态矢量研究表明,采用库仑应力算法得到的时间序列前兆变化更明显,对目标地震... 相似文献
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本文尝试采用一种类似于加卸载响应比的简单算法将GPS观测应用于地震中短期预测.算法根据孕震区域在不同阶段的加卸载响应比变化判断未来地震的发生趋势:当地壳处于稳定状态时,得到的时间序列在1.0附近波动;而在临近地震之前会出现明显的异常高值.以2004年美国南加州的Parkfield地震为例对方法的有效性进行了研究,发现在地震发生前半年左右震中附近GPS台站得到加卸载响应比时间序列都发生了比较明显的异常变化;而一些距离震中较远台站却没有观察到类似的异常变化.这可能反映了孕震区地壳介质稳定性的变化,表明通过处理GPS观测资料可能获得新的地震前兆异常. 相似文献
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对加卸载响应比理论在地震预测中的应用进行分析,提出了对“正地震”和“负地震”震级根据加载库仑应力的半日潮振幅进行加权的研究思路,并应用于1999年台湾集集地震、2002年阿拉斯加Denali地震和2003年日本Hokkaido地震的震前加卸载响应比的计算。结果表明,相比较传统加卸载响应比,权重加卸载响应比更能突出震前的异常信息。 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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基于加卸载响应比理论,对2017年8月9日新疆精河6.6级地震前加卸载响应比时空演化特征和异常区的孕震积分时程曲线进行分析。结果表明,在精河6.6级地震前,研究区出现了明显的加卸载响应比高值异常区域,异常区呈现环状特征;而且,异常区域随时间逐渐向震源附近迁移,异常演化过程中异常区域内部和周围发生了6次5级以上地震,其中,2次6级地震发生在异常高值减弱过程中,异常峰值到发震的时间分别为11、22个月,大于以往研究的理论发震时间,这可能是受构造应力区域性特征影响的缘故。 相似文献
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加卸载响应比理论用于矿震预测的初步研究 总被引：4，自引：0，他引：4
加卸载响应比(LURR)理论是一种前景很好的中期地震预测方法,通常在强烈地震发生前的数月至1～2年LURR出现高值,因而LURR可以作为强烈天然地震的前兆,用此方法曾经成功地预测过Northridge地震(1994年1月17日,M6.7,美国加州),Kanto地震(1996年9月11日,M6.6,日本)及不少发生在中国的天然地震。用房山煤矿1992年8月至1993年7月的微震资料,计算了全年内7组M>2.1矿震前的加卸载响应比Y值,其中5组矿震前Y值均明显大于1(Y≥2.9)。以上结果表明,加卸载响应比理论有可能用于矿震的预测。 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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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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We calculated the Coulomb failure stress change generated by the 1976 Tangshan earthquake that is projected onto the fault planes and slip directions of large subsequent aftershocks.Results of previous studies on the seismic fail-ure distribution,crustal velocity and viscosity structures of the Tangshan earthquake are used as model constraints.Effects of the local pore fluid pressure and impact of soft medium near the fault are also considered.Our result shows that the subsequent Luanxian and Ninghe earthquakes occurred in the regions with a positive Coulomb fail-ure stress produced by the Tangshan earthquake.To study the triggering effect of the Tangshan,Luanxian,and Ninghe earthquakes on the follow-up small earthquakes,we first evaluate the possible focal mechanisms of small earthquakes according to the regional stress field and co-seismic slip distributions derived from previous studies,assuming the amplitude of regional tectonic stress as 10 MPa.By projecting the stress changes generated by the above three earthquakes onto the possible fault planes and slip directions of small earthquakes,we find that the "butterfly" distribution pattern of increased Coulomb failure stress is consistent with the spatial distribution of follow-up earthquakes,and 95% of the aftershocks occurred in regions where Coulomb failure stresses increase,indicating that the former large earthquakes modulated occurrences of follow-up earthquakes in the Tangshan earthquake sequence.This result has some significance in rapid assessment of aftershock hazard after a large earthquake.If detailed failure distribution,seismogenic fault in the focal area and their slip features can be rapidly determined after a large earthquake,our algorithm can be used to predict the locations of large aftershocks. 相似文献
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以南北地震带北部的青藏高原东北边缘与华北构造区过渡部位为例,通过建立地震构造模型,计算静态库仑破裂应力改变量（ΔCFS）,研究了该区1561~1920年360年间5次M≥7级地震之间的触发过程.结果表明,在1561年罗山东麓71/4级地震之后,下一次地震无一例外地发生在前面地震产生的应力触发区（ΔCFS>0）.在4条被触发的发震断裂中,有3条发震断裂的平均ΔCFS>0.2×105 Pa,最大可达0.62×105 Pa,超出目前普遍认为触发应力阀值（0.1×105 Pa）.根据断裂库仑破裂应力变化量（ΔCFS）和构造应力累计率（δτ）,计算获得了下一次地震发生的提前量（ΔT）,地震活动提前量最大可以达到160a.在一条重要活动构造带或地区上,一次地震发生对下一次地震的触发缩短了地震重复发生所需要的累积时间,使得地震可以提前发生,这一方面使得某一特定的发震断裂在时间尺度表现出准周期性,另一方面使得空间上不同发震断裂的地震活动表现出丛集发生的现象.此项研究有助于认识断裂间相互作用特点、揭示地震丛集发生规律以及预测未来地震危险区. 相似文献
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The current implementation of LURR (Load/Unload Response Ratio) theory has shown promise in intermediate to short-term earthquake forecasting through past practice, but has also met difficulties at the same time. In this paper a new implementation of LURR method is presented to address one of the problems. The major change in the new implementation is that LURR values will result from a calculated maximum faulting orientation (MFO) instead of any focal mechanism selected by users. After comparison with the world stress map, the calculated MFO has been found to be in good agreement with the observation from the regional tectonic stress regime. The MFO pattern in the Indonesia region has a special feature which may be related to the unique subduction complexity. The MFO pattern in the Sumatra region in general is different from that in the Java region after the 2004 M 9.0 Sumatra Andaman Islands earthquake. This phenomenon may be supported by the evidence of the recent observation that a section in the southern part of the Sumatran arc is locked. Furthermore, the MFO pattern before the 2004 main shock is different from that after the event. Retrospective examination of the Indonesia region by means of this implementation can produce significant LURR anomaly not only prior to the 2004 main shock but also before the 2006 M 7.7 South Java earthquake. Therefore future great earthquakes might favorably be forecasted if the LURR anomaly detected by MFO method could be considered a precursor. 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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发震构造特性是潜在震源区划分及其地震年发生率确定的重要依据。潜在震源区除了反映“未来具有发生破坏性地震的地区”的内涵外,还应反映高震级档地震具有相似复发特征的涵义。由于在地震活动性参数统计单元内,有一些具有不同本底地震的活动构造块体,为更好地反映地震活动的空间不均匀性,考虑潜在震源区的三级划分是有必要的。通过分析潜在震源区内高震级档地震的复发特征,计算预测时段内潜在震源区的高震级档地震的发震概率,采用预测时段内概率等效转换获得地震年平均发生率的方法,有助于在中国地震危险性分析框架内考虑潜在震源区的强震复发特性。另外,文中还对潜在震源区内特征地震次级震级档频度不足的特性和发震构造上强震非均匀性在地震危险性分析中的应用问题进行了探讨 相似文献
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DISCUSSION ON THE SEISMOGENIC STRUCTURE OF THE 2016 MENYUAN M6.4 EARTHQUAKE IN MENYUAN,QINGHAI 
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下载免费PDF全文 On January 21, 2016, a M6.4 earthquake occurred in Menyuan county, Qinghai Province. Its epicenter is located in the Qilian-Hexi Zoulang tectonic zone, which records several moderate-large historical earthquakes. Previous studies on this event are based on geology, remote sensing data and focal mechanism solutions, lacking analysis on its seismogenic structure. In order to study seismogenic fault plane and seismoteconic style of the earthquake, this work uses data of seismic intensity, aftershocks, and geology to address this issue. Furthermore, we calculate Coulomb stress changes imposed by the 1927 Gulang M8 and 1986 Menyuan M6.4 earthquake on the fault plane of the 2016 Menyuan M6.4 earthquake. The results indicate the early two events have posed distinct impacts on two nodal planes:loading or triggering on nodal plane Ⅰ, and unloading or delay on Ⅱ. In some cases such triggering stress is approaching or up to the threshold value of 0.01 MPa. Combining isoseismals, aftershock distribution, geological structure and different Coulomb stress changes aforementioned, the nodal plane Ⅱ of the source model is considered the seismogenic feature. In conjunction with geophysical data, we establish the seismogenic model of the Menyuan earthquake, which is a positive flower structure in a profile, gentle in the upper and steep in the lower, characterized by thrusting in a strike slipping fault system. This is a possible model for thrusting earthquakes generated by strike-slip faults in a compressional tectonic regime. 相似文献