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引言地震波的衰减问题,人们很早就十分重视并进行了研究。对于近震P波的衰减问题,在国内,最近十年才有比较多的人去研究。研究近震P波的衰减问题可归结为测定介质的品质因子Q值。测定Q值的方法主要有时间域的方法和频率域的方法两大类。文中列举了笔者和其他研究者用不同的方法在不同地区测定的Q值。从总体上看,Q值在100—1350之间,大多数在200—600之间。详细研究了唐山和海城震区的Q值后得到:1、在大地震(大余震)前后,震区的Q值发生明显变化,震前大,震后小。2、在大地震余震活动区的边缘部位,若仍保持着较大的Q值,则很可能是较大余震的发生地。文章最后对造成近震P波衰减的主要原因进行了讨论,认为主要是由于地壳表层的严重不均匀性造成地震波
Introduction The problem of attenuation of seismic waves has long been paid great attention to and studied. For the attenuation of near-Earth P-wave, in our country, there have been more people in the recent ten years to study. Research on the attenuation of near-P waves can be attributed to the quality factor Q of the medium. The method of determining Q value mainly has two methods of time domain method and frequency domain method. The article lists the author and other researchers using different methods in different regions of the determination of Q value. Overall, the Q value is between 100-1350, mostly between 200-600. After a detailed study of Q values in Tangshan and Haicheng earthquake regions, we can get: 1. Before and after a large earthquake (Great aftershock), the Q value of the earthquake region changed obviously. 2, in the edge of the earthquake area of aftershock activity, if still maintain a large Q value, it is likely to be the occurrence of a larger aftershock. Finally, the paper discusses the main reasons for the P wave attenuation caused by near-Earthquakes, and concludes that the seismic wave is mainly caused by the serious inhomogeneity of the crustal surface