Revision of the Allegedly Deadly and Tsunamigenic 1843 Earthquake at Chalke Island, South Aegean Sea, Greece

Abstract Previous studies based on secondhand information sources stated that on 6 or 18 October 1843, a death toll as high as 600 was caused by a mainshock that ruptured near the small island of Chalke in the southeast Aegean Sea, Greece. Previous studies report maximum intensity Im (in modified Mercalli [MM] or in European Macroseismic Scale-98) and Ms or Mw magnitude estimates range from VIII to IX and from 6.4 to 6.75, respectively. It was claimed that a powerful tsunami also caused. Examination of a set of primary (original) sources not utilized by previous authors allowed revisiting the parameters of the earthquake and its macroseismic effects. The mainshock occurred at Chalke on 17 September 1843, and the occurrences of foreshocks and aftershocks were documented. The mainshock caused some damage in poorly constructed houses while landslides and rock falls were triggered. No fatalities and no tsunami generation were reported. The Im value assigned is VII–VIII. From magnitude/intensity empirical relationships Mw 5.93 was calculated. The 1843 earthquake is a characteristic example of an extreme exaggeration of the consequences of an earthquake when important primary sources were not consulted.