Spectrum Deviation Method of Identification of Foreshocks or Generalized Foreshocks and Its Applications

Based on previous research work,we present a spectrum deviation method to recognize a foreshock or generalized foreshock in this paper. The criterion to determine whether an event is a foreshock is a wide spectrum for an ordinary event,however,a moderate earthquake with foreshock or generalized foreshock has the characteristics of a narrow frequency band,and it deviates to the low frequency. It may be explained by metastable extension in the rupture source or related area of the main shock or regional fragmentation damage and crack nucleation process. The calculation results of two foreshocks,the M_S4. 7 event which occurred before the Yushu M_S7. 1 earthquake on April 14,2010 and the M_S5. 3 event which occurred before the Yutian M_S7. 3 earthquake on February 12,2014,show that the spectra of foreshocks shift,and they are quite different from the nonforeshock seismic spectrum of equivalent size. Therefore,this result can verify the validity of the spectrum deviation method.

Numerical method of slope failure probability based on Bishop model

Based on Bishop's model and by applying the first and second order mean deviations method, an approximative solution method for the first and second order partial derivatives of functional function was deduced according to numerical analysis theory. After complicated multi-independent variables implicit functional function was simplified to be a single independent variable implicit function and rule of calculating derivative for composite function was combined with principle of the mean deviations method, an approximative solution format of implicit functional function was established through Taylor expansion series and iterative solution approach of reliability degree index was given synchronously. An engineering example was analyzed by the method. The result shows its absolute error is only 0.78% as compared with accurate solution.

Evaluation of regional water security using water poverty index

Water security is a widely concerned issue in the world nowadays.A new method,water poverty index(WPI),was applied to evaluate the regional water security.Twelve state farms in Heilongjiang Province,Northeastern China were selected to evaluate water security status based on the data of 2006 using WPI and mean deviation grading method.The method of WPI includes five key indices:resources(R),access(A),capacity(C),utilization(U)and environment(E).Each key index further consists of several sub-indices.According to the results of WPI,the grade of each farm was calculated by using the method of mean deviation grading.Thus,the radar images can be protracted of each farm.From the radar images,the conclusions can be drawn that the WPI values of Farm 853 and Hongqiling are under very safe status,while that of Farm Raohe is under safe status,those of Farms Youyi,597,852,291 and Jiangchuan are under moderate safe status,that of Farm Beixing is under low safe status and those of Farm Shuangyashan,Shuguang and Baoshan are under unsafe status.The results from this study can provide basic information for decision making on rational utilization of water resources and regulations for regional water safety guarantee system.