3, INTERNAL FORCES OF RELIEF - RELIEF: - Is the shape of the Eath’s surface - It’s caused by internal forces that originate inside the Earth. - these forces: 1. can move, raise or sink the land. -2.act through:- Pressures - Earthquakes - Volcanoes
2. INTERNAL FORCES OF RELIEF - There are continual pressures along the boundaries of the tectonic plates. - Pressures can cause: 1. FOLDS: - Are deformations of the Earth’s surface when rock layers bend. - Types: a) anticline: when rock layers fold upward. b) syncline: when rock layers fold downwards. 2. FAULTS: -Are breaks in rock layers when rock is too hard to bend. - Parts: a) hanging wall: is the land that is pushed up b) Footwall: is the lower land.
2. INTERNAL FORCES OF RELIEF EARTHQUAKES -
Are caused when the Earth’s crust is shaken. - They occur along the boundaries of tectonic plates, where plates slide against each other. - Energy is released in seismic waves : - from a focus or hypocentre (inside the Earth) - to the epicentre (a point on the Earth’s surface that is above the hypocentre).
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Many of them: -are imperceptible to human beings (tremors) - they can be detected with special instruments (seismographs). Others are extremely destructive. Earthquakes in the ocean floor called tsunami Tsunamis: - are huge tidal waves - can produce great damage and destruction in coastal areas.
2. INTERNAL FORCES OF RELIEF VOLCANOES VOLCANO: - Is a crack on the Earth’s crust - when it erupts rise to the surface hot liquid rocks called MAGMA. - when magma emerges to the surface called LAVA - Lava flows and ash clouds can cause great damage. - PROCESS AND PARTS: 1. Rocks,gases and ashes are ejected through the main channel called VENT 2. Material is deposited all arount and form the CRATER 3. Lava flows out and becomes solid 4. Lava flows and solid rocks accumulate and form the CONE