The Time Features of Seismic Regime

Abstract

The recent increased emphasis on identifying earthquake precursors has led to increased interest in the time regularities of seismic regime. This chapter deals with focus migration in space and time over the polygon as a whole, together with the variations over time in the activity in individual small zones with elevated epicentre densities. We compare the spatial and time characteristics for tremors of various classes, and we examine whether the seismic process is stationary or if there is periodicity in seismic activity. At the end of the chapter, we discuss the relationship between these features of the weak seismicity and the strong earthquakes that have occurred in the polygon or near it, particularly in order to estimate the prognostic possibilities of the weak seismicity.