GEOLOGY

Detailed explanation-1: -A volcano is a feature in Earth’s crust where molten rock is squeezed out onto the Earth’s surface. This molten rock is called magma when it is beneath the surface and lava when it erupts, or flows out, from a volcano. Along with lava, volcanoes also release gases, ash, and solid rock.

Detailed explanation-2: -Several hazards may affect the area around the volcano, such as lava flows, pyroclastic flows, lahars, jökulhlaups and landslides or debris avalanches. Volcanic activity also produces hazards that can affect areas far from the volcano, such as tephra or ash falls, releases of gas and tsunamis.

Detailed explanation-3: -Magma is extremely hot liquid and semi-liquid rock located under Earth’s surface. When magma flows onto Earth’s surface, it is called lava.

Detailed explanation-4: -Lava flows are rivers of incandescent of molten rock or lava moving downslope or away from an eruption vent.

Detailed explanation-5: -Volcanologists use the word ‘tephra’ as general term for volcanic rock fragments irrespective of grain size produced during an explosive eruption. Volcanic ash is fine tephra, and terms such as lapilli, blocks, and bombs are used to categorize larger fragments.