辽宁省烈度速报算法研究及其在灯塔地震中的检验

Research and Testing of an Intensity Rapid Report Algorithm for the Dengta M_S5.1 Earthquake in Liaoning

立足于辽宁省烈度速报的实际需求,在多种地震烈度算法的研究基础上,结合震害实际,从滤波、场地校正、网格计算、烈度计算、已知震源计算等方面进行探索和试验,提出一种新的实时地震烈度计算的方法,并在辽阳灯塔5.1级地震中得到实际检验。

When making strategic disaster relief decisions,rapid and effective intensity assessment and distribution results are of utmost importance.For this process,an intensity rapid report algorithm is necessary,especially in areas such as Liaoning.In the study process,following principles must be followed：（1）The intensity grade must adhere to the Chinese Seismic Intensity Scale to communicate the instrumental intensity and maintain continuity of the intensity assessment.（2）With respect to the physical ground motion parameter,a 0.3-10Hz band-pass filter must be selected because the main frequency bands of housing structures in China fall into this range.（3）When selecting the ground motion parameters of the instrumental intensity,the effect of three ground motion component histories for this intensity must be considered.（4）The method must be simple and general for overall use,and the results should be stable and reliable.We calculated the seismic intensity in Liaoning by the following steps：（1）Modification of the correction of the field effect using ShakeMap Small Regression.（2）Grid computation for real-time systems,which reduces the amount of computation but may also reduce the accuracy of the intensity map.（3）Filtration and intensity calculation.We use a band-pass filter in the 0.3-10Hz frequency domain,filter the three-component ground motion histories,and then synthesize the acceleration time history.Finally,we calculate intensity values using the Chinese intensity method.（4）Plotting intensity distribution.We constructed a rough and uniform simulation station grid using an existing station acceleration value and determined the intensity value of the station by its acceleration or velocity.The intensity of the simulation station is constructed using the equal-distance interpolation method.We then plot the distribution of the equivalent seismic intensity in the entire region from the intensity of grid points.Combined with the actual seismic damage results and network density,we draw the intensity distribution map using the source of a fault zone.Finally,considering the Dengta MS5.1earthquake in Liaoning as a test case,the intensity distribution map was automatically produced by the intensity quick report data processing system called Samrt in 10 min,which also produced a detailed acceleration distribution diagram and intensity distribution map in 30 min.These results prove that the proposed method is feasible.