Earth Planets Space, Vol. 51 (No. 10), pp. 1099-1117, 1999
B. D. Enescu, D. Enescu, and A. P. Constantin
National Institute for Earth Physics, P.O.Box MG-2, Bucharest-Magurele, 76900, Romania
(Received October 28, 1998; Revised February 21, 1999; Accepted April 19, 1999)
Abstract: Diagrams from electromagnetic data that were recorded at Muntele Rou Observatory during the periods from December 1996 to January 1997, and December 1997 to September 1998 were plotted. The times when Vrancea earthquakes of magnitudes M3.9 occurred within these periods are marked on the diagrams.
The magnetic data prove that Vrancea earthquakes are preceded by magnetic perturbations that may be regarded as their short-term precursors. Some of these perturbations may also be regarded either as geomagnetic storms or as instrument effects.
Perturbations, which could likewise be seen as short-term precursors of Vrancea earthquakes, are also noticed in the electric records. Still, a number of electric data do cast a doubt on their forerunning nature.
Some suggestions are made in the end of the paper on how electromagnetic research should go ahead to be of use for Vrancea earthquake prediction.