'earthquake-prone' originates from Modern English, specifically the compound 'earthquake' + 'prone', where 'earthquake' itself comes from Old English elements 'earth' (from Old English 'eorthe' meaning 'ground, soil') and 'quake' (from Old English 'cwacian' meaning 'to tremble'), and 'prone' originates from Latin 'pronus' meaning 'inclined (forward)' via Old French/Medieval Latin.

'earthquake' changed from Middle English forms like 'erthequake' (a combination of 'earth' + 'quake') and eventually became the modern English 'earthquake'; 'prone' entered English via Old French/Medieval Latin from Latin 'pronus' and was used in Middle English to mean 'inclined' before developing the modern sense used in compounds.

Initially, the elements described 'earth' and 'quake' (trembling of the ground) and 'prone' meant 'inclined'; over time the compound came to mean 'situated in or characteristic of a place likely to suffer earthquakes', a meaning that has been stable in modern usage.