Intermediate-term earthquake prediction for the Vrancea region: Analysis of new data
This paper deals with intermediate-term earthquake prediction (CN algorithm) in Vrancea, using data on the intermediate-depth seismicity from the Romanian local seismic network. Vrancea is not a typical region for an application of the CN algorithm. Usually CN is used to predict shallow earthquakes in a region with linear extents of a few hundred kilometers. Most of the Vrancea seismicity is concentrated within a very narrow zone and at intermediate depths. In this paper the CN algorithm was designed to predict intermediate-depth earthquakes using intermediate-depth seismicity only. For the period 1932 to 1993, four out of five earthquakes of magnitude 6.4 and above were preceded by alarms, the alarm time occupying 21.7% of the total time period. The results of a retrospective test indicate the possibility of monitoring the preparation of large Vrancea earthquakes, provided a regular updating of the catalog is being done using data from the Romanian local seismic network.