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151.
历史地震资料与地震的中长期预测 总被引:1,自引:0,他引:1
故障诊断模型的基本内容是根据动态系统的外部特征来判断系统内部是否发生故障及确定故障发生的部位、时间和大小。由于故障诊断技术在监测及诊断故障的思路上和地震预报有很多相似之处,因此,把故障诊断技术应用于地震预报是可行的。由于该模型与其他数学模型一样,需要有较多的学习过程,所以历史地震资料在该模型中有重要作用。而其中的鲁棒性故障诊断模型在抑制各子模型的个性,凸现其共性方面有其特有的性质,所以把它作为一种综合模型,能抑制各子模型的个性,突出在地震预测方面的共性,从而提高预测的精确性。本文根据一个实例,说明了这种综合性模型的可行性。在文章的最后,由信息量的分析,说明了模型的鲁棒性特征。 相似文献
152.
分析了“十五”期间社会,政府对防震减灾工作的需求,联系工作实际进行了全面论述和分析,并对推进防震减灾提出了一些有益的政策建议。 相似文献
153.
对永胜6级地震的预报及依据 总被引:2,自引:1,他引:2
2001年10月27日在云南永胜发生6.0级地震,震前四川省地震局有较准确的中期和短临预报,加强了川滇交界地区的地震监测预报工作,并且向四川省政府作了汇报,取得了明显的社会效益。经验性地震预报重视川滇菱形地块西界断裂带动态活动图像的分析,尤其对历史强震破裂空段附近出现的中小震活动带或新活跃区段的研究;同时,重视4级前震群、川滇交界地区地下水位、水温、形变观测异常的跟踪分析和震情预测。 相似文献
154.
155.
岩石破裂实验,地球岩石层断裂构造运动,地震孕育、发生和发展过程等研究表明,地震活动的时间、空间和强度分布特征具有分形结构。作为一种分维理论的应用,本文利用厦门数字化地震遥测台网的数据,采用信息的分析方法,对福建省的地震多发区-漳州、华安、龙岩地区的地震活动进行了分析和研究,讨论了信息维随时间变化的特征。 相似文献
156.
157.
Horizontal and vertical components of earthquake ground motions at liquefiable sites 总被引:1,自引:0,他引:1
Field observations on ground motions from recent earthquakes imply that current knowledge is limited with regard to relating vertical and horizontal motions at liquefiable sites. This paper describes a study with the purpose of clarifying this emerging issue to some extent. A series of numerical analyses is carried out on a liquefiable soil deposit with a verified, fully coupled, nonlinear procedure. It is shown that the transformation of vertical motions in the deposit differs considerably from the transformation of horizontal motions. Both the amplitude and frequency content of the horizontal motions are strongly dependent on the shaking level or the associated nonlinear soil behavior. The transfer function for vertical motions is however likely to be independent of the intensity of input motions; no reduction in the amplitude occurs even in the case of strong shaking. The results are shown to be in consistence with the laboratory observations on shaking table tests and recent field observations that less nonlinearity exists for vertical motions. It is also shown that the possibility exists for using information on spectral ratios between the horizontal and vertical surface motions to quickly identify in situ soil behavior and liquefaction that are not readily covered by conventional field or laboratory experimentation procedures. 相似文献
158.
We examined the hypothesis that minima in local recurrence time, TL, or equivalently maxima in local probability, PL, may map asperities in the Kanto and Tokai areas of Japan, where the earthquake catalog of the National Research Institute for Earth Science and Disaster Prevention (NIED) is complete at the M=1.5 (M1.5) level. We mapped TL (PL) based on the a- and b-values of the nearest earthquakes within 20 km of every node of a grid spaced 0.01° for M7 target events. Only earthquakes within the top 33 km were used. The b-values increase strongly with depth, in several areas. Therefore, some of the TL (PL) anomalies are not revealed if data from the entire crustal seismogenic zone are mixed. Thus, we mapped TL (PL) separately for the top 15 km and the rest of the depth range, as well as for the entire seismogenic crust. The resulting TL- and PL-maps show that approximately 12% of the total area shows anomalously short recurrence times. Out of six shallow target events with M≥6.5 and which occurred since 1890, five are located within the anomalous areas with TL <450 years. We interpret this to mean that areas with anomalously short TL map asperities, which are more likely than other areas to generate future target events. The probability that this result is due to chance is vanishingly small. The great Kanto rupture of 1923 appears to have initiated in the most significant asperity we mapped in the study area. One anomaly is located in the northeastern part of the area of the proposed future rupture of the Tokai earthquake, and another one at its southwestern corner. The absolute values of TL calculated are uncertain because they depend on the size of the volume used for the calculation. 相似文献
159.
MODIFIED MASS FLUX CUMULUS CONVECTIVE PARAMETERIZATION SCHEME AND ITS SIMULATION EXPERIMENT—PART Ⅰ:MASS FLUX SCHEME AND ITS SIMULATION OF THE 1991 FLOOD EVENT* 下载免费PDF全文
Based on the existing cumulus convective parameterization schemes,a mass flux scheme (MFS) for cumulus convective parameterization has been successfully developed by reference to the work of Chen et al. (1996).The MFS is a comprehensive scheme.In MFS,not only the importance of the large-scale moisture convergence is taken into account,but also it includes the cumulus updrafts and downdrafts,cumulus-induced subsidence in the environmental air.entrainment,detrainment and evaporation.The interaction between the cumulus and the environment is described by using a one-dimensional bulk model.At the same time the scheme includes the penetrative and shallow convections.The MFS has been successfully incorporated into the regional climate model RegCM2 developed by NCAR.The new model has been applied to simulate summer monsoon characteristics and their variations of heavy rainfall process in the Changjiang-Huaihe River Basins for three months from May to July 1991.The results show that the new model can successfully simulate this rainfall prolonged process.By comparising the model outputs of RegCM2.using the Kuo scheme and the MFS.it is found that the MFS is better in simulating the surface temperature,rainfall position and amount,and rainfall duration. 相似文献
160.
针对地震静校正存在的非线性和多参数性等问题,本文提出了一种全局优化的剩余静校正方法.在模型更新规则上,把模拟退火方法和均匀优化设计方法结合在一起,使模型的更新更为合理,从而加快了搜寻全局最优解的速度.同时提出了模型的不同分量的温度参数和退火过程的选取方式,把温度参数的选取与地震剖面的能量联系起来,使温度参数的选取具有自适应的特点.该方法克服了常规模拟退火方法所具有的寻优空间不均匀以及退火参数需通过多次试验选取的缺陷.通过实际地震资料的计算证明,本文提出的方法对地震静校正问题合理而有效. 相似文献