The Recent Progress in Astroseismology Study in Yunnan
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Graphical Abstract
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Abstract
The recent progress in astroseismology study in Yunnan after 1996 is summarized in this paper.The breakthrough in some scientific fields is specially discussed.The main contents are as follows: 1.The triggering effect of the tidal force on the seism (1)The seisms responding to the different triggering effects have different distribution in location.The seisms are often triggered in a relatively concentrated period. (2)The seismic center with the largest tidal force is not the sub-stellar point of the Sun and the Moon.The Sun and the Moon are even not in the elevated region of 54.7° where is the zenith distance of the seism center,but are about 90°.In other words,the Sun,the Moon,the Earth center and the seismic center are not in one straight line.Judging from this,The main factor of triggering the seism is the horizontal component of the tidal force. (3)It is demonstrated that the triggering effect of the tidal force on the seism is,in substance,the effect of the advance slide on the seismic fault. 2.The relation between other special positions of the heave solar system objects and the seism. Some special points are called as astronomical strange points.The points include that at which certain planets are in opposition or conjunction to the Moon,and the points at which some of the heave solar system objects are in the elevated region of 54.7° where is the zenith distance of the seism center.And some special positions of the lunar longitude ascending node,as well as some special phases of the obliquity of the lunar path and equator are all belong to this category.It is shown that the astronomical strange points and eruptions of the seism are closely related. 3.The relation among the Earth rotation,the time-latitude residual and the eruption of the seism. It is found that the increase of the Earth rotation speed can cause large seism.The unusual time-latitude residual and the eruption of the seism observed are closely related. 4.The modulation effect of solar activity on seism activity It is found that various cycles of solar activities can give the modulation effect on the cycles of seism activities.There is also the cycle of 22 years for the seism events.In the 20th century there are four periods during which the seisms were frequently appeared:1917-1931,1941-1952,1966-1976 and 1988-1996.In the active period of the seism the eruption of the large seism follows a non-linear acceleration law.
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