The categories

basic characteristics and distribution law of seismic fracture were introduced

theoretical analysis study on the features and failure characteristics of various types of seismic fractures was conducted from their development scale and instability mechanism

the distribution

development characteristics

deformation signs of seismic fractures were explored and combined with the stress intensity factor method

the shattering injury mechanisms of structure surface was analyzed by use of rock fracture mechanics mechanism.The research results show:（1）The seismic fractures are divided into six types:surface type

transfixing type

strike type

tendency type

closure type and extension type from its morphological characteristics and deformation signs;（2）On the whole the Seismic fractures has 30°N-60°E trend;（3）The seismic fractures mainly distributed in seismogenic faults area or ridge and steep with slow border area

high open degree

fillings less or no.（4）The mechanism of seismic fractures belongs to tensile crack

the deformation and failure process of structural planes of rock mass under dynamic action is divided into rupture

expansion and penetration three stages.