Plate Tectonics and Earth Hazards

Plate Tectonics and Earth Hazards

• Tectonic plates are large pieces of the Earth's lithosphere, constantly moving.
• Plate boundaries are points where these plates meet.
• Convection currents within the Earth's mantle drive plate movement.
• Earthquakes occur at plate boundaries when rocks break and shift, releasing seismic waves.
• Volcanoes are formed when magma rises to the surface at plate boundaries.
• Primary hazards are immediate dangers from a tectonic event, while secondary hazards are long-term consequences.
• Primary hazards include things like ground shaking, lava flows, and tsunamis
• Secondary hazards include things like fires, disease, breathing difficulties and landslides
• Responses are actions taken by humans after a hazard.

Structure of the Earth

• The Earth has different layers: crust, mantle, and core.
• The crust is the outermost layer, divided into tectonic plates.
• The mantle is the layer beneath the crust, which is partially molten and contains convection currents.
• The core is the innermost layer, composed mainly of iron and nickel, existing in both solid and liquid forms.
• The lithosphere is the crust and the uppermost part of the mantle.

Volcanic Types

• Volcanoes are categorized by their shape and eruptive style.
• Shield volcanoes are broad, gentle-sloped volcanoes, associated with relatively fluid lavas.
• Composite volcanoes are cone-shaped volcanoes formed from layers of ejected materials like ash and lava, with violent eruptions.

Earthquakes

• Earthquakes are sudden ground movements caused by the release of energy stored in rocks at plate boundaries.
• The Moment Magnitude Scale measures earthquake strength based on the seismic waves generated which are ten times greater than the previous number, with each step

Impacts of Hazards

• Hazards have physical and human impacts that can be short term or long term
• Factors affecting impacts of volcanoes and earthquakes include the type of volcano, preparedness, population density, and location.

The Nepalese Earthquake 2015

• The earthquake occurred on a collision plate boundary between the Indian and Eurasian plates.
• The earthquake focused was 8 km deep and the epicenter was 60 km northeast of Kathmandu.
• Significant impacts included widespread destruction of homes, injuries and loss of life, impact on UNESCO World Heritage sites and on harvests and tourism.
• Short-term responses involved rescue efforts and aid provision.
• Long-term responses involved rebuilding efforts and developing disaster preparedness plans.