龙门山和成都地震构造区的划分

新编制的地震动参数区划图采用了潜在震源区三级划分方案，以体现背景地震活动空间分布的不均匀性，并在地震构造区内归纳出统一的地震构造模型。本文根据西南地区潜在震源区三级划分的成果，分析了龙门山地震统计区内的龙门山和成都地震构造区的基本特征，历史地震活动强度及频度，主要活动构造的构造变形样式，建立了地震构造区的发震构造模型，确定了构造区的本地地震及划分构造源的地震构造标志。同时，提出了确定背景源空间分布函数的简单方法。

Seismotectonic Zonation of the Longmengshan and Chengdu Region

The principle of three-level delineation is adopted in determination of a potential seismic source for the new National Seismic Ground Motion Parameters Zoning Map of China, to embody the inhomogeneity of the spatial distribution of background seismic activity and induct a uniform seismotectonic model for each seismotectonic region. Based on achievements of determining potential seismic sources in southwestern China, this paper introduces the basic characteristics, historical earthquakes magnitude and frequency distribution, identification of deformation mechanism of main active tectonic structures for the Longmenshan and Chengdu seismotectonic region in the Longmenshan seismic region, establishes the seismogenic model for each seismotectonic region, and identifies the upper limit of background earthquakes. A simple method is also put forward for calculating the spatial distribution function of a background seismic source.