| With the constant progress of the earthquake early warning technology, earthquakeearly warning is playing a more and more important role inpreventingearthquake andreducingproblem. Earthquake location is a basic problem of seismology, and it is also aprimary issue in earthquake early warning. Unlikely conventional earthquake location,earthquake early warning location can only use very little information, and the timelinessis demanding. Precision and speed of the positioning of the earthquake early warningdecides whether earthquake early-warning succeed or not. This paper summarizescommon earthquake early-warning positioning methods at home and abroad forreference. It makes a research onthe timeliness of the positioning of earthquake earlywarning. The time of triggered by the stations is effectively used.And also the paper putsforward the concept of positioning reliability and error of the radius. On the premise ofthe positioning precision, minimize the location time. Of course, it is testedby the actualearthquake cases. At the same time, basing on Fujian digital seismic network, we assessthe location ability in Fujian area earthquake earlywarning system. In this paper, mainwork is as follows:1．This paper summarizes the world development situation of earthquake earlywarning, introducing common earthquake early-warning positioning methods at homeand abroad. Earthquake early warning locating method is divided into three categories:the ground motion amplitude attenuation method, the method of P wave initial stage’sgrowth rate at ground motion amplitude and computational geometry method. Theground motion amplitude attenuation method is empirical method, but the deviation isvery large. P wave initial growth methods have B-Δ ground motion amplitude method,C-Δ method, A-Δ method, etc. It is widely used in a single warning system.Computational geometry method consists of Voronoi diagram location and equal timeface positioning method. Voronoi diagram positioning method has higher requirementson the order of the triggered station. Equal time face positioning method, essentiallyusing different arrival information to calculate hyperboloid, is the main method andthe?methodrepresentatively. There has been many kinds of integrated use of the abovemethod in positioning internationally, and it has been relatively mature.2．The paper is based onJinxing, Zhang Hongcai (2012) who put forward a set offour sets of earthquake early warning based on continuous positioning method,effectivelyusingthe waiting time of station trigger, reducing the possible epicenter areain realtime, implementing from single to double to three to four dynamic and continuouspositioning. In order to avoidthe process of positioning without solution as grid spacingis too large, local refinement grid algorithm is proposed. Putting forward the concept ofpositioning reliability and deviation of the radius, and combining the example on April20,2013Lushan earthquake inSichuan province and on September4,2013, Xianyouearthquake in Fujian province.Analysis shows that the waiting time and positioningreliability ensure the positioning accuracy and also can effectively reduce the positioningtime. It will save more valuable time forthe emergency measures to avoid earthquake.3. Combining Fujian digital seismic network and using the Voronoi diagramtheory and positioning reliability, we evaluate the Voronoi diagram of Fujian networkpositioning accuracy. We discretize land area in Fujian by grid, assuming that each gridpoint is a child source. And applyingthe real-time positioning method, this paperobtained Fujian region under the different radius of positioning reliability and deviationof positioning accuracy and positioning time contour. According to a series of contour,the earthquake early warning practice application can be adopted according to thedifferent requirements to takethe corresponding positioning reliability and deviationradius, which can be used to ensure to maximize the function of earthquake earlywarning system. |
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