Jörn received his diploma in Geophysics from Free University, Berlin, in 1998. In his diploma thesis, he worked on travel time tomography of two seismic profiles near Calama, Northern Chile. Between 1998 and 2003, he was member of the TRANSALP Group at the GFZ Potsdam and studied the crustal and upper mantle seismic structure of the Eastern Alps. He finished his PhD in 2003. Since 2003, he has been working in the KTB seismic monitoring team focusing on fluid-induced microseismicity. In August 2005 he joined the microseismicity group at the Free University, Berlin and continues his research in seismic source location, multiplet analysis as well as source parameter determination.