Interior of the earth: Just read these solved multiple choice and short questions answer and get 100% marks of short question in the examination.
- The earths radius is 6370 km.
- The gold mines in South Africa is 3-4 km deep.
- “Deep ocean drilling project”, “integrated ocean drilling project” etc. are the project related to the study of the interior of the earth.
- Deepest drill in the world is Kola in Arctic ocean.
- The reading of the gravity at different places is different, because it is influenced by several other factors. It is known as gravity anomaly.
- The point where the energy is released is called the focus of an earthquake.
- The point on the surface, nearest to the focus, is called epicenter.
- An instrument called “seismograph” records the waves reaching the surface. Richter scale is used in this instrument to measure the intensity of earthquake.
- Among the three types of earthquake wave (P,S and L), ‘L’ wave is responsible for the destruction of any kind of features on the earth surface.
- ‘P’ waves are similar to the sound waves. And it is faster than other two types of earthquake waves.
- P waves can travel through gaseous, liquid and solid materials.
- S waves can travel through solid materials only.
- The between 105 degree and 145 degree from the epicenter is identified as the shadow zone.
- The earthquakes are generated due to sliding of rocks along a fault plane, is known as tectonic earthquake.
- Collapse earthquake mainly occurred in the mining area, due to the collapse of the roofs of the mines.
- The magnitude of the earthquake is measured by Richter scale (0-10).
- The intensity of the earthquake is measured by Mercalli scale (1-12).
- The earth crust:
Thickness – 5 in oceanic crust and 30 km in the continental crust.
It is up to 70 km in Himalayan region.
- Density- 3g/cm3
Oceanic crust is mainly formed by basalt rock.
- The Mantle:
The boundary line between the earth crust and the mantle is known as Moho’s discontinuity.
The mantle extends from Moho’s discontinuity to a depth of 2900km.
The upper part of the mantle us known as asthenosphere (The source.
Density – 3.4g/cm3.
- The core:
Depth – 2900-6300km.
Density – 5g/cm3.
- Hawaiian volcanoes are the best example of shield volcanoes.
- The mid oceanic ridge in the Atlantic ocean is about 70,000km long.
- Sill, dyke, lacolith, phacolith, batholiths etc. are the examples of intrusive volcanic landforms.
- Caldera, lava plateau, lava mesa etc. are the examples of extrusive volcanic landforms.
- Lacoliths are large dome shaped intrusive bodies with a level base and connected by a pipe-like conduit from below. In the Karnataka plateau such type of landforms are found.
- Dykes are commonly found in the western Maharashtra area.