On some problems of seismic crustal phase

In this paper, some practical problems in seismological observations are discussed on the identification of seismic crustal phase, such as: “whether (Pg) and (Sg) are direct waves or not?”; “whether (Sg) and Lg as well as IIg and (Pg) are two kinds of waves or identical wave?”; “on seismological phases in regional travel-time table”; “on the symbols and identifications of phases in seismological observation reports”; “on the relation betweenm _Lg andM _L”, and so on. Some confused ideas on these problems are clarified.