TRANS-AEGEAN SEISMICITY, SEISMIC HAZARD AND DEFENCES

摘要

Observation and analysis of both micro- and macroearthquakes is vital to understanding and preparation of multi-facetted and in-depth earthquake defences. Therefore the paper revisits simple, yet fundamentally important maps of macroearthquake felt effects in Turkey which modem techniques extend to statistically interpretable hazard and zoning maps. Such mapping should ultimately be extended well beyond peak ground acceleration to a larger, more representative suite of earthquake hazard parameters for advisory purposes. Both vigilance and rapid reaction dominate exploitation of microearthquakes. Rapid reaction resulted in a seismic network around the Athens 1999 September 15 earthquake, and 450 locally recorded aftershocks identify the fault plane (strike 117°, dip 52°) consistently with teleseismic observations. Longer term monitoring in central Greece associated with swarms at Pavliani and with Egion 1995 June 15 aftershocks provides physical properties during rupture: stress drop, coseismic slip length etc. and scaling relations between seismic moment and slip. In the case of Pavliani coseismic slip is mapped in 2D throughout a pseudo fault-zone that lacks a history of any major earthquake. The ultimate vigilance and rapid reaction in defence are embodied by earthquake early warning. An embryonic early warning demonstration system associated with liquid natural gas storage near Athens is introduced.