  Ionospheric TEC (Total Electron Content) variations derived from GPS
measurements at 17 stations before and after the 2009 Abruzzo earthquake (EQ)
of magnitude Mw6.3 were processed and analyzed. The analysis included
interpolated and non-interpolated TEC data. Variations in the TEC of both
regional and local characteristics were revealed. Several regional changes were
observed in the studied period: 1 Jan-21 Apr. 2009. After analyzing
non-interpolated TEC data of 5 GPS stations in Central Italy (Unpg (Perugia),
Untr, Aqui (Aquila), M0se (Roma) and Paca (Palma)), a local disturbance of TEC
was also found. This local TEC disturbance arises preparatory to the EQ main
shock occurred at 01:32 UT on 06 April 2009, maximizes its amplitude of ~ 0.8
TECu after the shock moment and disappears after it. The TEC disturbance was
localized at heights below 160 km, i.e. in the lower ionosphere.
