长江下游地区地震的日月周期性

根据重力固体潮理论值公式,计算长江下游地区地震(M_s≥5.0,1900～1990)的各位相值,按Schuster检验和χ2检验进行判定,发现该地区的地震具有下述非随机的月亮和太阳的周期性:(1)半日周期,表现为太阳时角变化的半周期(P_R=0.023,χ2=7.576)和半日固体潮周期(P_R=0.017,χ2=8.167);(2)半月周期,表现为半个朔望月周期(P_R=0.011,χ2=8.985)和双周潮周期(P_R=0.061,χ2=5.588);(3)对M_s≥5.1地震,还显示出1年的周期,太阳黄经的P_R=0.035,χ2=6.712。对M_s≥5.2地震,还存在半个月球近地点黄经变化周期(P_R=0.043,χ2=6.309)。

LUNAR AND SOLAR PERIODICITIES OF EARTHQUAKES IN LOWER CHANGJIANG RIVER REGION

Phases of mainshocks (M≥5.0,19001990) in the lower Changjiang River region (3034°N,116122°E) in the Eastern China were determined by means of the formulaser for the theoretical tidal gravity.Distributions of lunar and solar hour angles,lunar and solar ecliptic longitudes,luni-solar phases,and phases of the 8.85-yr lunar perigee cycle and the 18.6-yr lunar nodal cycle of these samples were evaluated by Schuster's test and chi-square test for which the formula used in Kilston Si Knopoff (1983) was modified into (6) in this paper.To avoid fortuity,especially in the case of smaller sample,and missing some possible periodicities,the samples with magnitude from 5.0 to 5.7 were tested one by one.Phases of the semidiurnal and fortnightly theoretical tidal gravity were also determined and evaluated.This investigation has uncovered that the principal earthquakes in the study region show statistically non-random lunar and solar periodicities as follows: 1.semidiurnal periodicities displayed