Randolph, Tennessee in the area since 1974 occurred on August 19, 1994 – the temblor was measured 3.2 on the Richter scale with an epicenter at coordinates , ca. west of Randolph, at a depth of . On January 16, 2009 at 3:09 p.m. local time (21:09 UTC), "a small earthquake shook portions of Tipton County". The earthquake was measured at a magnitude 2.8 on the Richter scale. According to the Center for Earthquake Research and Information (CERI), the epicenter of the temblor was reported to be at coordinates at a depth of . There were no reports of damage caused by
Order of magnitude An order-of-magnitude difference between two values is a factor of 10. For example, the mass of the planet Saturn is 95 times that of Earth, so Saturn is "two orders of magnitude" more massive than Earth. Order-of-magnitude differences are called decades when measured on a logarithmic scale. Other orders of magnitude may be calculated using bases other than 10. The ancient Greeks ranked the nighttime brightness of celestial bodies by 6 levels in which each level was the fifth root of one hundred (about 2.512) as bright as the nearest weaker level of brightness, and thus the brightest level being