The Dunedin earthquake of 9 April, 1974 was of magnitude 5.0, and is the largest known to have originated in eastern Otago. The shock was centred about 10 km south of the city centre, with a shallow focus, probably about 20 km deep. Damage to a value of about $250,000 occurred, and many brick chimneys were broken or damaged in the worst affected areas, where the intensity reached MM VII. The areas of greatest damage were the southern suburbs, on alluvial soils, where results from a survey of natural seismic noise show strong amplification effects due to the unconsolidated nature of the ground.