"Mercalli scale." YourDictionary, n.d. Web. 14 January 2019. <https://www.yourdictionary.com/mercalli-scale>.
Mercalli scale. (n.d.). Retrieved January 14th, 2019, from https://www.yourdictionary.com/mercalli-scale
A scale of earthquake intensity based on observed effects and ranging from I (detectable only with instruments) to XII (causing almost total destruction). It is named after the Italian seismologist Giuseppe Mercalli.