D. ENESCU
Centrul de Fizica Pamantului si Seismologie, Bucuresti – Magurele
SOME FEATURES OF THE VRANCEA EARTHQUAKES
(Abstract)
A comparative analysis between isoseismal line general shape and nodal plane
orientation of local mechanism solutions for all Vrancea intermediate depth
earthquakes, having both macroseismic maps and fault plane solutions is made.
On the basis of this analysis and by means of synthetic isoseismal line computations
one infers that focal mechanism is the main determining factor of isoseismal
line general shape for Vrancea intermediate depth earthquakes.
The accelerograms recorded during the strong earthquake of March 4, 1977 and
the synthetic accelerograms which were calculated for several Romanian sites
allowed to establish a relation (expressed by the curve in figure 3) between
maximum horizontal ground movement acceleration and macroseismic intensity.
This relation and macroseismic data concerning the two large Vrancea earthquakes
of this century (November 10, 1940; M = 7,4 and March 4, 1977, M = 7,2) and
the crustal earthquakes were used to draw out the maximum horizontal acceleration
maps in figures 4 and 5.