Far from having me shaking in fear and panic, the recent earthquake has spurred me on to research the word itself.
It has long been used in reference to the ground shaking, as well as people and objects trembling. In Middle English, it appears in a great many forms, such as quaken, cwaken, hwaken, and so forth. Here is an example from the South English Legendary, from around 1300:
Þe eorþe bi-gan to quake, Ase wide ase þe cite was
(The earth began to quake, all across the city.)
It did not start its story in English there. Going back to Old English, we can again find it in reference to an earthquake, such as in the Old English version of Orosius’ History Against the Pagans, from the Alfredan translation programme, during the 880s;
Seó eorþe wæs cwaciende
(the earth was quaking).
In this example, the verb used is cwacian, meaning “quake, tremble” and could even be used to refer to the chattering of teeth.
No cognates for the word are known in other languages, and it is not known where the Old English word might have come from.