First results of the CRLN seismic network in the western Corinth Rift: evidence for old-fault reactivation

The 12 stations Corinth Rift Laboratory Seismological Network (CRLNET) aims at monitoring the seismicity (Ml>1) in the CRL area and at constraining the geometry of active structures at depth. Two years of microseismicity (2000–2001) recorded by the CRLNET in the Aigion area shows: (1) background seismicity inside the Corinth rift at depth of 4.5–11 km, deepening towards the north and no activity in the upper 4 km of the crust – this seismicity is not clearly related to major faults observed at the surface –; (2) a swarm, 6 km south of the city of Aigion, associated with the Mw=4.2, 8 April 2001 earthquake. This earthquake occurred at 6 km depth, on a SW–NE oriented fault dipping 40° to the northwest and corresponds to normal faulting with a right lateral component of slip. It likely occurred on an old structure reactivated in the present stress field. To cite this article: H. Lyon-Caen et al., C. R. Geoscience 336 (2004).