earthquakes and volcanoes (geography)

what is the focus?

the point underground where an earthquake starts

what is the epicentre?

the point on the Earth’s surface directly above the focus

what is a shallow focus earthquake?

an earthquake where the focus is close to the Earth’s surface

what is a deep focus earthquake?

an earthquake where the focus is deeper underground

why can shallow focus earthquakes cause more damage?

energy travels a shorter distance, so less energy is lost, creating stronger shaking at the surface, therefore there’s more damage

why can’t deep focus earthquakes cause less damage?

energy travels a longer distance, so more energy is lost, creating weaker shaking at the surface, therefore there’s less damage

how are the focus and epicentre related?

the epicentre is directly above the focus on the Earth’s surface

how can volcanic activity cause climate change?

volcanoes release ash and gases such as sulphur dioxide. these can block sunlight, meaning less solar energy will reach the earth

what are primary effects of volcanoes?

effects that happen directly because of the eruption. e.g lava, ash, and pyroclastic flows

what are secondary effects of volcanoes?

effects that happen as a result of primary effects. e.g flooding, disease and lack of clean water

why can secondary effects sometimes be worse than primary affects?

they can affect a larger area and last longer, causing further problems such as disease, flooding and lack of clean water