The Bubnoff unit (abbreviated B) is a unit of speed equal to . 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
Geology () is a branch of natural science concerned with Earth and other astronomical objects, the features or rocks of which it is composed, and the processes by which they change over time. Modern geology significantly overlaps all other Ea ...
to measure rates of lowering of earth surfaces due to
erosion
Erosion is the action of surface processes (such as water flow or wind) that removes soil, rock, or dissolved material from one location on the Earth's crust, and then transports it to another location where it is deposited. Erosion is dis ...
and is named after the Russian (German-Baltic) geologist
Serge von Bubnoff (1888–1957). An erosion speed of 1 B also means that 1 m
3 of earth is being removed from an area of 1 km
2 in 1 year. Compared to everyday phenomena, erosion is under most circumstances (excluding rapid events like
landslides
Landslides, also known as landslips, are several forms of mass wasting that may include a wide range of ground movements, such as rockfalls, deep-seated slope failures, mudflows, and debris flows. Landslides occur in a variety of environments, ...
) an extremely slow process, calling for such a specialized unit. For instance, the current average rate of erosion over the Earth's landmasses has been estimated at 30 B (30 m in a million years). There are, however, great regional differences in erosion speed. As an extreme example, the
watershed area of the
Semani River in
Albania
Albania ( ; sq, Shqipëri or ), or , also or . officially the Republic of Albania ( sq, Republika e Shqipërisë), is a country in Southeastern Europe. It is located on the Adriatic and Ionian Seas within the Mediterranean Sea and shares ...
is eroding at a rate of almost 3000 B (3 millimeters per year), the river having been estimated to transport about 4600 tons of earth per year from the average square kilometer in its watershed.
The Bubnoff unit was introduced because of a desire for a standard unit to replace the multitude of units in use, such as feet per year, centimeters per year, meters per decade, and so on. One criticism leveled was that by introducing the Bubnoff unit, it would obscure the rate of erosion behind a unit no one besides specialists understood.
1
m/s is equal to approximately 31,540,000,000,000 B.
References
Non-SI metric units
Units of velocity
Geomorphology
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