本文分析了霍山地区十年来的地震资料,得到了如下的认识:霍山小地震的频度峰值同华北南部地区的中强地震有较好的对应关系。根据霍山地区三个台站的中小地震的P波初动符号得出了各台的平均机制解,由此推断了该区的区域应力场;并推测该区似应处于华北块体的南部边界。这一特殊构造部位及介质条件可能是上述“窗口”效应的原因。 This paper analyzes the seismic data of Huoshan area over the past 10 years and obtains the following findings: The peak frequency of the Huoshan earthquake is in good correspondence with the moderate-strong earthquakes in the southern part of North China. Based on the P-wave primary motions of three small stations in Huoshan area, the average mechanism solution of each station is obtained, and the regional stress field of the station is inferred. It is speculated that this area should be located at the southern boundary of North China block . This particular tectonic location and media conditions may be the reason for the “window” effect described above.