Tag: our changing earth

An earthquake is the sudden shaking of the surface of the Earth, resulting from the sudden release of energy in the Earth's lithosphere that creates seismic waves. Earthquakes can be violent enough to toss people around and destroy whole cities. The seismicity or seismic activity of an area refers to the frequency, type and size of earthquakes experienced over a period of time.

Mud flows are a flowage of water-saturated earth material possessing a high degree of fluidity during movement. A less-saturated flowing mass is often called a debris flow. A mudflow originating on the flank of a volcano which generally flows through the surface of the Earth.

• Magma, when comes out on the surface of the earth through the volcanic opening, is called lava, hence option C is correct.
• The vent is the volcanic opening on earth's surface.
• Cone is the structure of the volcano formed as a heap of cooled materials that come out of volcanic eruptions
• The magma chamber is the pool of magma beneath the surface of the earth.

Rotation is the movement of the earth on its axis. The earth takes about 24 hours to complete one rotation on its axis. The period of rotation is known as the earth day. This is the daily motion of the earth.

Glacial deposition is the settling of sediments left behind by a moving glacier. As glaciers move over the land, they pick up sediments and rocks. The mixture of unsorted sediment deposits carried by the glacier is called glacial till. Piles of till deposited along the edges of past glaciers are called moraines.

Drumlin, oval or elongated hill believed to have been formed by the streamlined movement of glacial ice sheets across rock debris, or till. The name is derived from the Gaelic word druim (“rounded hill,” or “mound”) and first appeared in 1833.

Larger pieces of rock that are encrusted in till or deposited on the surface are called "glacial eratics". They range in size from pebbles to boulders, but as they are often moved great distances, they may be drastically different from the material upon which they are found.

Fluvioglacial landforms are landforms molded by glacial meltwater. This discharge of glacial streams, both over the surface and beneath the ice sheet, is higher in the warmer summer months. As subglacial water often flows under pressure, it has a high velocity and is very turbulent.

The Earth is a non-luminous body but the sun is luminous. As the earth is rotating around its axis, half of its portion is facing the sun and the other half is entirely dark due to the absence of sun. In other words, half of the globe have day and on the other half, it is a night. As the earth is rotating around the sun its every part is exposed to Sun within every 24 hours this rotation causes days and nights.

Barkan is a crescent-shaped sand dune produced by the action of wind predominately from one direction. One of the commonest types of dunes, it occurs in sandy deserts all over the world.