为新区划图编制所建立的地震动衰减关系

Development of Ground Motion Attenuation Relations for the New Seismic Hazard Map of China

介绍了建立新一代地震区划图所采用的地震动参数衰减关系的总体思路,并从资料、衰减关系分区、衰减关系模型、回归方法、转换等方面说明了地震动参数衰减关系的建立过程,给出了我国分区地震烈度和地震动参数衰减关系结果。新的地震动衰减关系的建立,具有如下特点:一是基于更加丰富可靠的强震记录和烈度资料;二是采用了具有大震近场饱和特征的地震动衰减模型;三是采用了使结果更加稳定的分步回归方法;四是在地震动衰减关系分区时考虑了地震活动性特征。与第四代地震区划图衰减关系相比,由于地震动衰减模型的变化和高震级强震记录的增加,高震级下的峰值加速度有所降低,而中强地震区的峰值加速度则在低震级时有所提高。

The general idea for establishing ground motion attenuation relations for the new seismic hazard map of China is introduced. The developing procedures are briefly summarized through strong motion data, attenuation zoning, attenuation model, regression strategy, and transformation. The development of the new attenuation relations is characterized by the following four aspects： more abundant data is based on; a model representing ground motion saturation is used; a more robust step-regression approach is applied; and a new attenuation zoning scheme is utilized. As compared with the attenuation relations used in the previous version of seismic hazard map of China, the predicted PGA for large earthquake in the new map is lower due to the application of the new attenuation model and more strong motion data in new field, while the predicted PGA for smaller earthquake is higher in moderate seismicity regions than before.