Source parameters of the 7 September 1999 Athens (Greece) earthquake based on teleseismic data

Eleni Louvari and Anastasia Kiratzi

Geophysical Laboratory, Aristotle University of Thessaloniki, 540 06 Thessaloniki, Greece (e-mail:

(Received 8 February 2000; accepted 21 April 2000)

Abstract: Far-field body waveform modeling and displacement spectral analysis are used to study the source parameters of the 7 September 1999 Athens earthquake (Mw=5.9). The earthquake was caused by the motion of a high-angle normal fault with strike=115o, dip=57o, rake=-80o, auxiliary plane with strike=277o, dip=34o, rake=-105o. The source time function reveals source duration of 4.2 sec, while more than 95% of the energy was abruptly released within the first 2.2 sec. The scalar seismic moment was found equal to 9.22*1017 Ntm. It is worth noting that the fault plane strikes in a WNW-ESE direction, having a small left lateral component of motion. The nearby Atalanti fault, which moved during the 1894 earthquake sequence, and caused severe damage to Athens, has about the same strike orientation. The spectral analysis, assuming a rectangular fault, yielded a fault length L=18 km, fault width w=10 km, stress drop Ds =9 bars, and average dislocation û =30 cm. These values are in agreement with those expected from the empirical scaling relations applicable to Greece.

Key Words: Focal mechanism; Source parameters; Athens earthquake; Greece