Data acquisition from 1996-2002 was divided into five separate field deployments: one in 1996 and 1997 in western Crete, one in 1999 on the small island Gavdos, south of Crete, one in 2000/2001 in the Messara plain in central Crete and finally one in 2002 in the gap between the western and central Crete networks south of Rethimnon. For all deployments, short period seismometers (Mark-L4-3D, S13, GS13 or CM-3) and PDAS100 dataloggers were used. In 1996 a network of six mini-arrays was installed on westen Crete. Each mini-array consist of a central three-component seismometer (A01-A06) surrounded by three vertical component seismometers (A110,A120,A130,A210,..) within a radius of about 300 m. The average distance between the cental stations was about 10 km. These central stations were re-used in 1997 and the network was extended to 47 stations (A001-A047) equipped with tree-component seismometers deployed all over western Crete except the Levka Ori. Although the network aperture was significantly increased from about 20 km to 60 km the station spacing was reduced to 5 km. 12 stations (GA01-GC03) were installed on Gavdos in 1999 with a network aperture of only 5 km limited to the size of the island. The dense spacing allows array methods for the detection and localisation of seismicity. In 2000/2001 an 8 station network (M001-M008) was located around the Messara plain in central Crete. The maximum aperture of this network was 50 km in EW and 20 km in NS direction. To close the gap in the seismicity observation between western and central Crete 7 stations (R01-R07) were installed south of Rethimnon in 2002. The seismic networks were originally planned as part of pre-site surveys for specific drilling proposals within the International Continental Drilling Program (ICDP). The networks provide the opportunity to image shallow seismically active zones of the Hellenic subduction zone. Waveform data is available from the GEOFON data centre, under network code YU, and is fully open.