Geography flashcards year 10

What is a Natural hazard?

A natural event that threatens people or has the potential to cause damage, destruction

What are Tectonic hazards?

Hazards caused by the movement of the Earth's tectonic plates (e.g.,earthquakes, volcanic eruptions).

What factors can increase the hazard risk?

Urbanisation, development, geographical location.

What are Atmospheric hazards?

Hazards created in the atmosphere (e.g., tropical storms, droughts).

What are the 4 layers of earth?

Inner core, outer core, mantle, crust

What causes tectonic plates to move?

Convection currents

Describe the distribution of earthquakes and volcanoes.

Trend: Most occur along plate boundaries

Example: For example around the Pacific plate.

Anomaly: Some earthquakes are found in the middle of plates e.g. North America

Which tectonic plate is subducted (forced down) at a destructive plate boundary? Why?

Oceanic is forced beneath the continental - because it is denser

What happens to the subducted plate

It melts, magma rises pushes against the surface, pressure builds, a composite volcano erupts.

Where is new land created?

At a constructive plate boundary. Plates move apart, magma rises, a shield volcano is formed. New land is created,

What is Hazard risk?

Refers to the probability of a natural hazard occurring.

What is an Earthquake?

A sudden or violent movement within the Earth's crust followed by a series of shocks.

What are Biological hazards?

Hazards posed by living organisms (e.g., forest fires).

What are Geomorphological hazards?

Hazards that originate near the Earth's surface (e.g., landslides, flooding).

What is Ridge Push?

When newly-formed plates at oceanic ridges (constructive plate margins) are warm and so have a higher elevation at the oceanic ridge than the colder, more dense plate material further away; gravity causes the higher plate at the ridge to push away, causing the plates to move away from each other.

What is Slab Pull?

The main force behind plate movement today, slab pull happens when a dense oceanic plate sinks into the mantle and drags the rest of the plate with it.

What are Convection Currents?

Heat from the Earth's core, caused by radioactive decay, heats the mantle. Rock in the mantle rises, cools and sinks down again. This is called a convection current.

What is the composition and density of Continental Crust?

Less dense, older, mainly granite

What is the composition and density of Oceanic Crust

Denser, younger, mainly basalt

What is a Hotspot?

Where volcanoes can form away from plate boundaries at hotspots, where magma rises through thin crust, such as in Hawaii.

What is Distribution?

The arrangement of a feature in space.

Where is Composite volcano formed?

Destructive plate boundary, where plates move into each other.

Where is a shield volcano formed?

Constructive boundary, where plates move away from each other.

What happens at a Constructive plate boundary?

At constructive plate margins, tectonic plates move apart, allowing magma to rise and form new crust. As plates separate under the ocean, magma rises and cools to createunderwater mountain chains called mid-ocean ridges. Volcanic eruptions and earthquakes can occur at constructive boundaries, often producing wide, low-profile shield volcanoes.

What happens at a Destructive plate boundary?

At destructive plate margins, tectonic plates move towards each other, often leading to subduction. When an oceanic plate collides with a continental plate, the denser oceanic plate is forced beneath, creating a subduction zone. The plate melts and magma collects in magma chambers. Friction and pressure at destructive margins cause powerful earthquakes and composite volcanic eruptions. Deep ocean trenches form where the oceanic plate bends and descends beneath another plate.

What happens at a Conservative plate boundary?

At conservative plate margins, tectonic plates slide past each other in the same or opposite directions at different speeds. Unlike constructive or destructive margins, no new crust is formed and none is destroyed. Plates can become stuck due to friction, causing stress to build up and release suddenly as an earthquake. Conservative margins do not produce volcanic activity because there is no subduction or magma rising.

What is the Subduction zone?

The site at which an oceanic plate is sliding under a continental plate.