In 455 AD a strong, presumably M ≥ 6.0, earthquake occurred in or near the ancient
town Savaria, the present Szombathely, West Hungary. According to the certainly incomplete
earthquake catalogue, since then no similar significant seismic event occurred during
the last 1500 years in this area which is currently considered inactive. Conclusions
of this study are: (1) According to contemporary written historical sources (Annales
Ravennates and biographical information about the life of Saint Severinus),
the earthquake that destroyed Savaria and occurred in 455 AD had a magnitude of M
≥ 6.0. (2) In order to support the aforementioned magnitude value calculations were
necessary. As the historical seismicity of the area is not known sufficiently an independent
geodynamical approach – in parallel to the Gutenberg-Richter relationship – was used
to estimate the return interval of earthquakes M ≥ 6. It was found in both cases that
in the Szombathely region the recurrence time of earthquakes M6 and M6.5 is 1000 and
3000 years. Consequently, the earthquake activity of the Szombathely region is significantly
lower than that of the Pannonian Basin in general.
