FITTING AN ELLIPSE TO THE SET OF INTENSITY DATA POINTS OF VRANCEA EARTHQUAKES
RASHID BURTIEV(1)
1. Moldavian Academy of Sciences, Institute of Geology and Seismology, 3 Academiei Str., Chisinau, Moldova
Abstract
Fitting an ellipse to the set of intensity data points of earthquakes occurred on 11.10.1940, 07.04.1977, 31.08.1986, 30.05.1990 and 31.05.1990 is performed. Test criteria indicate that the ellipse smoothes the observed line of macroseismic field. For all earthquakes, focal axes of 5, 6 and 7 EMS-98 intensity zones are directed along the y-axis. For other zones are oriented along the parallels. This fact is one more acknowledgement of the anisotropy of a geophysical medium. Approximation of the set of points with an ellipse is performed using the method proposed by Fitzgibbon.