  In this paper we present an approach for forecasting the imminent regional
seismic activity by using geomagnetic data and Earth tide data. The time
periods of seismic activity are the time periods around the Sun-Moon extreme of
the diurnal average value of the tide vector module. For analyzing the
geomagnetic data behaviour we use diurnal standard deviation of geomagnetic
vector components F for calculating the time variance Geomag Signal. The Sun
storm influence is avoided by using data for daily A-indexes (published by
NOAA). The precursor signal for forecasting the incoming regional seismic
activity is a simple function of the present and previous day Geomag Signal and
A-indexes values. The reliability of the geomagnetic when, regional precursor
is demonstrated by using statistical analysis of day difference between the
times of predicted and occurred earthquakes. The base of the analysis is a
natural hypothesis that the predicted earthquake is the one whose surface
energy density in the monitoring point is bigger than the energy densities of
all occurred earthquakes in the same period and region. The reliability of the
approach was tested using the INTERMAGNET stations data located in Bulgaria,
Panagurishte, PAG (Jan 1, 2008-Jan 29, 2014), Romania, Surlari, SUA (Jan 1,
2008-Jan 27, 2014), Italy, L'Aquila, AQU (Jan 1, 2008-May 30, 2013) in the time
of EU IRSES BlackSeaHazNet (2011-2014) project. The steps of program for
solving the when, where and how earthquake prediction problem are shortly
described.
