The Fault that Caused the Athens September 1999 Ms = 5.9 Earthquake: Field Observations     

Pavlides  S.B.  Papadopoulos  G.  Ganas  A. 《Natural Hazards》2002,27(1-2):61-84

On 7 September 1999 the Athens Metropolitan area (Greece) was hit by a moderate size (Ms = 5.9) earthquake. The severely damaged area is localized in the northwestern suburbs of the city, at the foothills of Mt. Parnitha (38.1°N, 23.6°E), about 18 km from the historic centre of Athens. In this paper, we present our results on the surface expression of the seismogenic structure. Methods applied were: field observations, geological mapping, fault geometry and kinematics, evaluation of macroseismic data, interpretation of LANDSAT images, construction of a DEM and application of shading techniques. Aftershock distribution and fault plane solutions were also considered. Our results suggest that the earthquake source is located within the NW-SE trending valley bearing a few outcrops of Neogene-Quaternary sediments across the south foothills of Mt. Parnitha, never known in the past to have been activated by such strong earthquakes. The earthquake occurred along a 10 km long normal fault, striking N110°–133° and dipping 64°–85°SW, extending from the Fili Fort (4th century BC) in the NNW to the Fili town and then to Ano Liossia, to the SSE. Tensional stress field with ₃ axis almost horizontal striking NNE-NE prevails in the area. The fault strike and the extensional direction (₃) are compatible with the focal mechanism of the main shock.  相似文献   

Deformation patterns associated with the M5.9 Athens (Greece) earthquake of 7 September 1999     

Gerassimos A. Papadopoulos  Hiroyuki Matsumoto  Athanassios Ganas  Vassilis Karastathis  Spyros Pavlides 《Journal of Seismology》2004,8(3):381-394

The static displacement field of the Athens 1999 earthquake has been numerically modeled by a BEM method and analysed from SAR interferometry images with compatible results: (a) for a fault that reaches the surface the subsidence field coincides with the hangingwall domain of the Fili neotectonic normal fault with maximum amplitude, d _max, 5.5–7 cm, which is consistent with the possibly co-seismic displacement of 6–10 cm observed in the field, the average fault dislocation of 5–8 cm found by the application of circular source models, and the displacement up to 6 cm predicted by empirical relations between magnitude and displacement; the field of uplift covers the footwall domain of the fault with d _max1.5 cm;d gradually decreases with distance from the fault at a gradient of 0.4 cm/km, (b) for a blind fault d _max is only 1.8 and 0.3 cm in the hangingwall and footwall, respectively, and the decay gradient becomes 0.15 cm/km, (c) the total deformation area is 15 km × 15 km and the Fili fault, with a preferred mean dip of 60°, constitutes the natural boundary between the subsidence and uplift areas. The macroseismic field pattern is similar with that of the static ground deformation. The majority of intensity values VI (MM and EMS-98 scales), are distributed within the hangingwall of the Fili fault, while the highest intensities (VIII and IX) concentrate very close to the Fili fault within its hangingwall domain. A gradual decrease of the intensities with the distance from the Fili fault is evident. Because of the similarity between the intensity distribution pattern and the static ground deformation pattern, we make the hypothesis that the latter predicts well enough the main characteristics of the former although the ground displacement is dominated by relatively low frequency as compared to the ground acceleration.  相似文献