Abstract: Sharing of seismic data greatly promote the progress of seismic science．Meanwhile,knowledge discovery for massive seismic data is advancing the development of seismic monitoring technology．Concept lattice is a powerful tool in knowledge discovery．Knowledge reduction,moreover,is one of the important aspects of knowledge discovery．Firstly,this paper used membership relationships defined to classify formal context,and simplified membership class by using granular membership reduction．And then,the reduced concept lattice was expanded by selecting objects and attributes dynamically,accordingly,the concept lattice of original formal context was converted eventually．Finally,typical examples of UCI database were analyzed．The results show that this method is effective and can simplify the objects and attributes in the maximum scale．The method is also applyied in the seismic database.

Key words: Seismic data,Concept lattice,Formal context,Granular membership reduction