基于震源机制解的分区地震烈度衰减关系研究

Study on Seismic Intensity Attenuation Relationship with Regions via Focal Mechanism Solutions

根据中国大陆构造应力场分区,本文拟合不同震源机制解的烈度衰减关系,收集了我国西部198次5.0级以上震例,共419条的等震线记录;东部47次5.0级以上震例,共84条等震线记录,采用椭圆模型进行衰减关系拟合,得到了地震烈度随震级和长短轴长度的衰减关系。文章初步分析了几种震源机制地震烈度衰减规律的差异,以西部地区为例,对比了西部走滑型、逆断型烈度衰减关系和汪素云西部衰减关系与实际值之间的差距。本文研究结果表明,区分发震方式的烈度衰减关系长短轴可以作为应急地震影响场的修正因子,在震后几小时得到震源机制解时,对烈度圈长短轴进行初步修正。

On the basis of regional division of tectonic stress field in China, we fit the seismic intensity attention relationships with different focal mechanism solution. The data we have collected includes 198 earthquakes and 419 isoseismal lines with Ms ≥ 5.0 in western China, altogether; 47 earthquakes and 84 isoseismal lines with Ms ≥ 5.0 in eastern China. By using the ellipse model fitting attenuation relation, seismic intensity attenuation relationship between the magnitude and the length of axis is established. In this paper, we preliminarily analyze the discrepancy between seismic intensity attenuation relationships of several focal mechanism solutions. Then, taking western China as an example, we compare western seismic intensity attenuation relationship of thrust fault and strike-slip fault with Wang Suyun＇s results, Our research results indicate that the length of axis of intensity attenuation relationship which have distinguished focal mechanism solutions could be a modifying factor for seismic influence field in case of emergency. When we obtain focal mechanism solution several hours after the earthquake, we can make a preliminary correction to the length of axis.