Tectonic Plates and Earthquakes

• The Earth's lithosphere consists of large rock slabs called tectonic plates, which fit together to form the Earth's crust.
• Faults are formed where two tectonic plates meet.
• Earthquakes are dangerous events triggered by sudden plate movements along faults, releasing energy in the form of waves.
• The shaking caused by these waves can damage homes and businesses.

Main Cause of Earthquakes

• The primary cause is the abrupt slippage of Earth's tectonic plates beneath the surface.
• Tectonic plates move due to their position atop a fluid layer of convection currents deep underground.
• Friction arises when the motion of plates brings them together.
• Continuous pressure from convection currents leads to the plates slipping when the pressure overcomes the friction.
• The sudden slip releases energy and tension, resulting in an earthquake.

Elastic Rebound Theory

• The buildup of tension when stretching a rubber band.
• The release of all the tension in the form of energy when the rubber band snaps.
• The elastic rebound theory explains that ground shaking occurs due to energy released from a fault slip.

Earthquake Zones

• Certain global regions are more prone to earthquakes due to frequent tectonic plate movement.
• Scientists analyze past earthquake data to forecast potential future events.

Ring of Fire

• It is a U-shaped zone along the Pacific Ocean coast, spanning over 24,900 miles.
• It connects many tectonic plates including the Pacific, Indian-Australia, Philippine, Eurasian, North American, Cocos, Nazca, Antarctic, Caribbean, and South American plates.
• Plate movement in the Ring of Fire accounts for over 81% of the world's earthquakes.

Alpide Belt

• The Alpide Belt traverses southern Eurasia.
• It accounts for over 17% of global earthquakes.
• It links the Eurasian, Arabian, Indian, African, and Australian plates.
• Pressure from these plates has formed the Alps and the Himalayas.

Oceanic Ridge Belt

• It is also known as the Mid-Atlantic Ridge.
• It lies between the North American, Eurasian, African, and South American plates.
• It is a divergent boundary where tectonic plates move apart.
• Locations near the epicenter, such as Iceland, experience strong earthquakes from this zone, even though the focus point is underwater.

Earthquake Events

• Earthquakes originate underground at the focus, where tectonic plates meet.
• Strong waves radiate outward to the Earth's surface.
• The epicenter is the point on the Earth's surface directly above the focus.
• The strongest waves can cause significant damage near the epicenter.
• Underwater earthquakes can cause tsunamis, generating destructive waves that impact nearby land.

Other Causes of Earthquakes

• Underground explosions such as nuclear explosions which are on a smaller scale.
• Collapses of large rocks which causes a shift in the Earth's crust, which can cause earthquakes.
• Volcanoes - Movement of lava beneath the surface leads to shifts in the crust, causing mild earthquakes.