Kola Superdeep Borehole
Also called: Kola well · Topic: Interior of the Earth: Earthquakes, Volcanoes and the Layered Earth · NCERT: Class 11, Ch 3 "Interior of the Earth"
Meaning
The Kola Superdeep Borehole is the deepest hole ever drilled. It reached 12,262 m (about 12.2 km) in 1989. It is a direct source of information about the interior, because it brought up real rock from deep in the crust. It found about 180 °C at the bottom, far hotter than expected. This showed that temperature rises faster with depth than scientists had thought. Even so, 12 km is tiny compared with the earth's radius of about 6,371 km.
Example
The borehole is on land, on the Kola Peninsula in Arctic Russia. NCERT describes it as "Kola, in Arctic Ocean, 12 km", but it is actually on the peninsula, not in the ocean. Exam questions use this as a trap.
Don't confuse with
- Deep ocean drilling projects (the Deep Ocean Drilling Project and the Integrated Ocean Drilling Project): these drill into the sea floor from ships. Kola was drilled on land.
Related concepts
- Direct sources of information about the interior
- Indirect sources of information about the interior
- Geothermal gradient
- Gravity anomaly