"Observing our environment from space: new solutions for a new millennium, proceedings of the 21st EARSeL Symposium, Paris, France, 14–16 May 2001", edited by Gérard Bégni, pub Taylor & Francis, 2002, p267 claims that the earthquake in the vicinity of Banja Luka in 1969 had a magnitude of 6.4. (Comparison of other earthquakes mentioned shows that this is 6.4 on the Richter scale.)Chronology of Extreme Weather, by Ken Polsson, claims: "magnitude 6.4 earthquake occurs. 20 killed, 150 seriously injured, and 65,000 left homeless."