Seismicity of Kecskemét area

Abstract

In the small seismic source zone of Kecskemet 203 earthquakes are known between 1739 and 2006, and about 90 percent of them have a magnitude value not more than 3.0, however the strongest event on July 8, 1911 has 5.6 surface-wave magnitude. Concerning the latter earthquake the maximum (epicentral) intensity I = VIII (EMS) was observed in the area enclosed by Kecskemet, Katonatelep and Hetenyegyhaza locations. The quake caused significant damage to buildings (I ≥ VI EMS) on about 6 thousands square kilometres and was felt (I ≥ III EMS) on some 85 thousands square kilometres. The focal depth is estimated as 11 km directly from the individual intensity data points. During the earthquake liquefaction (sand crater) occurred in the epicentral area and some electromagnetic effects were also observed. Studying the source dimensions we conclude the rupture area is between 40 and 67 square kilometres and the maximum displacement along the fault is estimated to 14–20 centimetres for the Kecskemet earthquake of July 8, 1911. A probabilistic seismic hazard assessment predicts 1.1–1.5 m/s2 peak ground accelerations, and 6.6–7.1 maximum (theoretical) earthquake intensity values with 10% chance of exceedance for an exposure time of 100 years in the studied area.