Earthquake mechanism

Abstract

The motion observed in the earthquake foci belongs evidently to the basic parameters of seismicity. Ideally, the earthquake catalogues should contain a heading of nodal plane solution for each shock. We shall not discuss the problems of theo­retical models, the technique of the construction of fault plane diagrams and diffi­culties in their interpretation or inconsistencies in the original data. In this field there are many questions still open, nevertheless the results of fault plane solutions may provide us with clues to the question how the earthquakes occur in the European focal zones.