A METHOD FOR THE DETERMINATION OF THE ENERGY OF EARTHQUAKES AND ITS APPLICATION TO THE EARTHQUAKES IN THE VRANCEA REGION

Dumitru Enescu

Abstract

The author presents a method for the determination of the energy of earthquakes using the dislocation theory [1] – [4] and applies it to the earthquakes in the Vrancea region. The method is treated by the author in papers [5] and [6].
The energy is computed for 10 earthquakes in Vrancea (Table) by means of the following formula deduced by the author for the theoretic seismic source corresponding to rupture associated with slipping:

where: a and c are the velocities of longitudinal respectively transverse waves within the medium of the focus;
– is the density of the medium
r – radius of the rupture surface in the focus
b – modulus of the vector of Burgers
ta and tc – times of increase of the first displacement in the longitudinal viz. transverse waves.
The E values obtained by means of this formula are in close agreement with the following energy – magnitude relationship [10]:

log E = 11.8 + 1.5 M.