SI derived unit SI derived unit SI derived units are units of measurement derived from the seven base units specified by the International System of Units (SI). They are either dimensionless or can be expressed as a product of one or more of the base units, possibly scaled by an appropriate power of exponentiation. The SI has special names for 22 of these derived units (for example, hertz, the SI unit of measurement of frequency), but the rest merely reflect their derivation: for example, the square metre (m), the SI derived unit of area; and the kilogram per cubic metre (kg/m or kg
Bubnoff unit Bubnoff unit The Bubnoff unit (abbreviated B) is a unit of speed equal to 1 m / 10 a. In other words, 1 B is equal to 1 meter in 1,000,000 years, 1 millimeter in 1,000 years, or one micrometer per year. It was defined in 1969. The Bubnoff unit is employed in geology to measure rates of lowering of earth surfaces due to erosion and is named after the Russian (German-Baltic) geologist Serge von Bubnoff (1888–1957). An erosion speed of 1 B also means that 1 m³ of earth is being removed from an area of 1 km² in