对汶川MS8.0地震的加速度峰值进行统计和处理,得到加速度(PGA)与断层距的统计关系、等值线图以及地震三方向的三维加速度图。发现加速度峰值沿断层方向衰减较慢,沿其它方向衰减较快,断层距在100km内衰减最快。大峰值的加速度基本位于断裂的两侧的狭长地带及沿断裂方向。用中国西部加速度衰减公式计算的加速度值与实际记录值进行比较,发现前者偏小并且衰减得快,可能与本次地震的断裂破裂机制和地质构造有关。
Based on the statistical and processing work for the peak acceleration data of Wenchuan MS8.0 earthquake in 2008,the statistical relationship between PGA and distance from the fault,PGA isogram and the 3-D acceleration diagrams in three directions are obtained.The results show that the peak acceleration attenuated slowly along the seismogenic fault,but attenuated rapidly in other directions,and the fastest decay appeared in the region within 100 km from the fault.High values of the peak acceleration commonly recorded in a narrow belt on both sides of the fault.Comparison of recorded values with values from the acceleration attenuation formula for west China shows that the latters are smaller and attenuate faster,it is consideredly related with the earthquake rupture mechanism and the tectonics.