1984, 6(s1):1-20.
Abstract:It is necessary to study physicochemically process and its precursors because the crust media and the earthquake process are very complex. Before an impending earthquake there is time dependence between the earthquake source process and its procursors. That could be interpreted from the viewpoint of slow crack propagation by stress-chemistry corrosion in fracture mechanics.
1984, 6(s1):21-33.
Abstract:In this paper, using the ultrasonic experiment of sandstone under uniaxial compression about P·S. wave, the variations of Vo Vs (velocities) Vp/Vs, Ap.As (amplitudes) As/Ap, initial frequency and midium transfer function before the crack of sandstone of high porosity have been studied The results are:1. Variation of Vp. Vs and Vp/Vs is the same as that of granite.2. Variation of Ap/As has taken place.3.The low frequency has increased.4. V ariation of medium transfer function has taken place 5 2-d P wave has been engendered.
1984, 6(s1):34-56.
Abstract:In the paper,we extend the time-distance equation of multiple reflection waves produced by surface earthquake source in homogeneous single layer medium with inclined boundary plane in seismic exploration to any depth of the focus, put forward a time-distance equation group of multiple reflection waves in laterally homogeneous single layer medium in which the velocity is linear correlation with depth and whose boundary plane is slant, and discuss the,relatioiiship between the ground displacement and the epicentral distance for multiple reflection waves.
1984, 6(s1):57-70.
Abstract:In order to study the kinematic and dynamic regional characteritics of seismic waves in the crust and the upper mantle of Gansu Province and its vicinity,we have used a series of data concerning the blasts and some earthquakes.
The results obtained are as follows:
1) The average velocity of the longitudinal wave from M discontinuity is 6.21-6.32 km/sec passing the crust and the upper mantle of Gansu.
2) Inclusive of the relative、thick sendimentary layer,the crustal thickness is 54 km in the west and 50 km in the east of the region,and in the other area it is 47 km.
3) The dominant frequenc of the reflected wave is stable before critic cal reflection.A possible model of the crust about this region is given% roughly.
1984, 6(s1):71-87.
Abstract:In this paper,several mothocis of impedance computation in non-uniform medium are analysed.lt is emphatically discussed to-use the Generalise Inverse Matrix Mothod in impedance Computation,to use the Information Matix to suppress cohereut noise and to define judgement indicator to measure the Level of coherent noise.At Last,the author poiuts out the saetteomiugs of various mothods and their improverrieuts.
1984, 6(s1):88-102.
Abstract:In this paper the following topics have been discussed:
1.Force source of forming large cracks in intraplate
2.The additional stress field on the brittle layer of the upper crust which is caused by the creep slip of large cracks on the basaltic layer at the bottom of crusts,and the order of this additional stress field have been estimated.
3.The effects of adjustmenta elements on the propagation of cracks by applying the conception of image force acted on dislocation by free surface in Solid physics.
4.The effects on the propagation of cracks when under focal faults surface exists the magmatic intrusion.
Sopyright:China Earthquake Engineering Journal