PATNET, the seismic network of the University of Patras, monitores regularly the seismic activity in the whole western Greece, using for a HYPO location a model, derived as an average representation for this broad area. One of the active regions of the western Greece is the Gulf of Corinth, which central part lies partially on the edge of the PATNET. Due to this and to the fact that the PATNET stations have mostly the vertical component only, the PATNET HYPO location of events in this region are often characterized by large standard errors in epicentres and especially in depths. Using a sequence of small earthquakes that occurred from February to May 2001 close to the city of Aigion, and was recorded by PATNET and as well by local Corinth rift laboratory (CRL) three-component network (CRLNET), we have derived for PATNET station and local model constants whose aplication improves the PATNET HYPO location of events in central part of Gulf of Corinth. These constants represent the main result useful for improvement of the future PATNET location in the given region., Jaromír Janský, Efthimios Sokos, Anna Serpetsidaki and Helene Lyon-Caen., and Obsahuje bibliografické odkazy