ON THE ATTENUATION OF SEISMIC WAVES THROUGH THE HAICHENG EARTHQUAKE AREA

From the results of 1 a set of theoretical curves used to determine the Q-value by means of the amplitudes of first P arrivals recorded at many stations are obtained in this paper. A portion of the aftershock data of the Haicheng earthquake of 1975 has been employed to determine the Q-value of the upper crust of the Haicheng region. Comparison with the Q_M-value of the top part of the upper mantle in this area obtained by the first P_n amplitudes data recorded at stations on the Liaodong Peninsula from some aftershocks of the 1976 Tangshan Earthquake sequence as well as some statistical results for the first half period of P and P_n suggest that there exist a difference in attenuation of the top part of the upper mantle between the southeastern portion of the Haicheng Earthquake region and other regions. This may imply that the deep materials there are melted in higher degree than in other parts of the area.