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51.
The load/unload response ratio YQ with the geophysical parameter coda Q-1 of the crust as response is denned in this study.The variation in YQ-1 before and after the Northridge earthquake of January 17,1994(California)has been investigated by using the data of coda Q-1 with frequencies of 1.5,3.0,6.0,12.0,and 24.0 Hz in the Southern California from 1987 to 1994.It can be found that YQ-1 for coda waves with all frequencies,the frequency of 12.0 Hz excluded,ascended to a certain extent prior to the occurrence of the rnainshock and returned to normality after the main shock.  相似文献   
52.
The temporal variation of LURR(y)for Kanto,Wakayama,and Hugo regions in Japan has been calculated and analysed.The LURR(y)values are significantly higher than 1 before the occurrence of all earthquakes with magnitude M≥6.0 in the Kanto region during the last two decades and the Kobe earthquake(1995-01-17).These results suggest that LURR theory is available for Japan.Recently they-value for Wakayama region has been near 1,while the y-value is remarkably larger than 1 for nearly two years for Kanto.According to these results,it is predicted that a strong earthquake with magnitude of about 6.0 could occur in 1 year or a little longer for in Kanto region or its adjacent regions,but there is little possibility for the Wakayama region.  相似文献   
53.
利用近代微震资料研究地震危险性   总被引:1,自引:0,他引:1  
刘杰  陈Yong 《中国地震》1997,13(1):10-17
利用1970~1993年华北地区ML≥2.0的微震资料,根据其地震活动特点,从中挑选了一些有代表性的区域,做其G-R关系曲线,由该曲线可得到每个震级的年频次,同时,由该区域的历史地震(1300-1993年)可得到较大震级的实际年频次,两者对比,发现具有很好的一致性。因此,当选取合适的区域时,利用近代微资料可以推测出该区域较大地震的活动情况,但同时有两点注意:(1)利用微震资料进行统计时,得到的得一  相似文献   
54.
用灰关联分析方法研究主震Ms≥6.0级地震序列类型的早期识别,主要对第一个强震后2天内地震序列资料进行分析研究,发现13次大震(Ms≥7.0)后1天和2天震型在关联识别正确率均为0.77(表1)36次强震(6.0≤Ms〈7.0)的均为0.83(表2,表3)。由此表明,灰关联分析方法是早期识别地震序列类型的一种比较有效的方法。  相似文献   
55.
黄金莉  赵大鹏 《地震学报》2003,25(6):563-573
应用南加州地震台网记录的6 347次区域地震的146 422个P波到时数据,并结合其它地震学方法所得到的莫霍面深度资料,在考虑莫霍面起伏变化下,确定了该区0~35 km深度内的精细三维P波速度模型.检测板分辨率实验结果说明了反演结果的可靠性.该模型提供了有关区域结构的重要信息,浅层P波速度结构与地表的地质特征相关,非常准确地反映了山脉盆地、地形地貌的差异;各深度层上的速度结构表现为分块特征,反映了以大型活动断裂为界勾画出的分区,如洛杉矶盆地、文图拉盆地、莫哈韦沙漠、半岛山脉、圣华金山谷、内华达山区及思尔顿凹槽区域整体变化的特征.圣安德列斯断层成为研究区内明显的边界,几个深度层上可以看到两侧的速度存在明显的差异,而横跨该断裂的几个剖面图上则显示了位于断层西南侧的太平洋板块区域速度较高、不均匀性较大,地震活动较深;位于断层东北部的北美板块速度偏低,非均匀性稍弱,地震活动性则较弱.比较平缓莫霍界面和起伏莫霍界面下反演得到的结果可以说明:莫霍界面的起伏对中下地壳层位速度结构的影响是明显的,尤其是在莫霍面深度变化较大的部位,这种影响更为强烈.带莫霍面形状的模型能更精确地计算射线路径和理论到时,从而使反演后的残差更小、结果更精确.   相似文献   
56.
Introduction The great Kunlun Mountain earthquake occurred on November 14, 2001 on the border be-tween Xinjiang and Qinghai in west China (36.2N, 90.9E). It was the largest earthquake oc-curred in Chinese mainland in the last 50 years. The Crustal Movement Observation Network of China (CMONOC) established in 1998 mainly for the purpose of earthquake prediction with only 25 fiducial stations for continuous GPS observations, has recorded the precious information of the crustal movement …  相似文献   
57.
高温高压下斜长岩纵波速度与电导率实验研究   总被引:2,自引:0,他引:2       下载免费PDF全文
在1.0 Pa、室温到880℃分别采用超声波透射法和阻抗谱法测量了斜长岩的纵波速度和电导率,并对实验产物进行了鉴定分析.结果表明,在680℃,由于斜长岩中的含水矿物绢云母和黝帘石发生脱水反应,岩石的纵波速度开始大幅度下降.在410℃~750℃、12~105 Hz的频率范围内,斜长岩只出现颗粒内部传导.由于脱水产生的自由水主要分布于矿物的三联点或颗粒拐角处,没有形成连通的高导性网络,因此,脱水作用不会导致斜长岩电导率显著增加,也不会改变其电传导机制.地球内部低速层和高导层的形成与演化可能具有非同步性,通过含水矿物脱水可以形成地球内部的低速层,但不一定同时形成高导层.   相似文献   
58.
The Heihe River drainage basin is one of the endangered ecological regions of China. The shortage of water resources is the bottleneck,which constrains the sustainable development of the region. Many scholars in China have done researches concerning this problem. Based on previous researches,this paper analyzed characteristics,tendencies,and causes of annual runoff variations in the Yingluo Gorge (1944-2005) and the Zhengyi Gorge (1954-2005),which are the boundaries of the upper reaches,the middle reaches,and the lower reaches of the Heihe River drainage basin,by wavelet analysis,wavelet neural network model,and GIS spatial analysis. The results show that: (1) annual runoff variations of the Yingluo Gorge have principal periods of 7 years and 25 years,and its increasing rate is 1.04 m3/s·10y; (2) annual runoff variations of the Zhengyi Gorge have principal periods of 6 years and 27 years,and its decreasing rate is 2.25 m3/s·10y; (3) prediction results show that: during 2006-2015,annual runoff variations of the Yingluo and Zhengyi gorges have ascending tendencies,and the increasing rates are respectively 2.04 m3/s·10y and 1.61 m3/s·10y; (4) the increase of annual runoff in the Yingluo Gorge has causal relationship with increased temperature and precipitation in the upper reaches,and the decrease of annual runoff in the Zhengyi Gorge in the past decades was mainly caused by the increased human consumption of water resources in the middle researches. The study results will provide scientific basis for making rational use and allocation schemes of water resources in the Heihe River drainage basin.  相似文献   
59.
This work evaluates objective functions for multiresponse non-linear modeling using computersimulations.Tests are performed under a variety of signal-to-noise ratios and noise variance-covariancestructures.The standard error of prediction for the model parameters,computed from 50 trials,is usedfor performance comparisons.The full rank and rank-deficient problems are considered.For the fullrank problem one model was investigated,a first-order two-step consecutive reaction model,and twoobjective functions were considered,the total sum of squares and the determinant criterion.Nodistinction could be made between the two objective functions for this model.For the rank-deficient case two models were investigated,a first-order two-step consecutive reactionas in the full rank case,and a pH titration model described by the Henderson-Hasselbalch equation.Three objective functions were investigated for the rank-deficient case,the total sum of squares,aweighted total sum of squares and the determinant criterion.The total sum of squares was found toperform poorly under all conditions tested compared to the weighted total sum of squares and thedeterminant criterion.The determinant criterion was found to perform much better than the other twocriteria when the data have a combination of a low signal-to-noise ratio and high variance-covariancenoise structure.  相似文献   
60.
样品经低温稀王水溶解 ,在选定的仪器条件下 ,用氯化亚锡还原 ,测定汞的吸收峰值。方法简便、快速、价廉 ,适用于大批化探样品的测定。  相似文献   
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