'earthquake-free' originates from Modern English, specifically the compound 'earthquake' + suffix '-free', where 'earth' comes from Old English 'eorðe' meaning 'ground', 'quake' comes from Old English 'cwacian' meaning 'to shake', and the suffix '-free' ultimately derives from Old English 'frēo' meaning 'without (free from)'.

'earthquake' developed from the Old English elements 'eorðe' and 'cwacian' into Middle and then Modern English as 'earthquake' (recorded from early modern usage), and the adjectival compound 'earthquake-free' is a later, productive Modern English formation using the suffix '-free'.

Initially 'earthquake' described the shaking of the earth; the compound 'earthquake-free' has meant 'without earthquakes' since its formation and has retained that basic sense.