强震等震线、余震区形状与地震构造关系的研究

本文通过对川滇和华北地区不同地震构造环境中, 1966年以来强震的等震线长宽比、 余震区长度的对比研究, 认为强震等震线的长宽比、 余震区长度都与地震构造环境和震级相关。 对于强震等震线的长宽比和余震区长度, 地震构造环境和震级的影响相同的是, 都与发震断裂是否位于活动地块边界, 位于哪一级活动地块边界, 是与边界方向一致的大断裂, 还是配套小断裂等有关。 最重要的是与活动断层的规模, 尤其是与发震断裂的长度有关, 也与震级有关。 不同的是, 强震等震线的长宽比明显受地表覆盖层的影响, 而余震区长度与地表覆盖层关系不明显, 似乎与震源破裂面长度的关系更密切。

Study on the Relation between Isoseismic Line, Aftershock Area of Strong Earthquakes and their Seismotectonic Environments

In this paper, isoseismic lines, aftershock areas of strong earthquakes in Sichuan-Yunnan area and North China with their Seismotectonic environment have been compared and studied. The main results are: ① Both the rates between the length and the width of isoseismic lines, and the lengths of aftershock area of strong earthquakes are related to the lengths of their seismogenic faults, and are related to their magnitudes too. ② The rates between the length and the width of isoseismic lines of strong earthquakes are also influenced by overburden in the region, but the lengths of aftershock area of strong earthquakes are not influenced by overburden in the region, maybe the latter can mainly reflect distribution of the seismogenic fault and nearby deep small faults.