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Abstract

Instr umental ear thquake monitoring in Greece star ted in 1899–1906 with the first five seismic stations of the National Obser vator y of Athens, Institute of Geodynamics (NOA). Subsequent upgrades and expansions led to today’s Unified National Seismic Network, which includes almost all permanent seismic stations in Greece and provides waveform and parametric data. We examine the detection capabilities of the Greek seismic networks using phase, location and magnitude data from the International Seismological Centre (ISC) and the various National Institutes. We apply two methods to measure the network performance. In one, we form a grid, and find the 50 per cent probability detection threshold for each station-grid cell pair for different times. In the other, we find the probability-based magnitude of completeness grid for every three months from 1970 to 2014. Both methods show that in 1990 the detection threshold improved significantly in the nor th par t of Greece. A much greater improvement took place in 2010 throughout Greece, yielding a completeness magnitude of M p ∼1.