A 30 to 35 m wide slice of a 100m height loess wall sank more than 10 m at the bank of the Danube near Dunaszekcso (Hungary) on 12th of February, 2008. Eötvös Lorand Geophysical Institute (ELGI) was requested a geophysical investigation of the area. ELGI deployed a system of six continuously operating seismic stations to observe the seismic micro-emissions. Two main source areas of seismic micro-emission were allocated after the data analysis. We made four points of CPT a depth of 12 m on the bank of the Danube and we have concluded that the movement of the loess wall was caused not by a sliding phenomenon. We used 121 units of RefTek 125 single channel autonomous seismic recorder and a vibrator as a source to make two seismic lines beneath and above the loess wall. Based on the structural imagefrom seismic tomography and reflection sections sedimentary layers of different thicknesses can be found on the old basement up to the level of the river Danube. The anomalies of the two profiles mark out a tectonic zone running in an approximately E-W direction.