Volcanoes And Earthquakes Flashcards
Pyroclastic flow
Smoke coming down the side of volcano
Radioactive decay
Where elements like potassium,uranium and thorium decay, which produces the earths heat.
Convection current
Where heat rises and then falls.
Plume
Rising magma.
Collision boundary
Where two plates move together (both continental crust). Seeing as continental crust can’t sink, the land between them is pushed together to form high ‘fold’ mountains (e.g. Himalayas). No volcanic eruptions occur here, but severe earthquakes do.
Constructive boundary
Where two plates move apart, forming a ‘gap’. Lava can easily escape in the form of a gentle eruption or a lava flow. As the lava cools, due to the water, it solidifies, creating a new oceanic crust, which forms a mid-ocean ridge.
Conservative
Where two plates try to slide slowly past each other. Occasionally they stick, which leads to a build up in pressure. When it releases, it creates severe earthquakes. No crust is created or destroyed, which mean that volcanoes don’t happen there.
Divergent boundary
A gap forms because the plates move apart (due to convection currents) which leads to shallow sided volcanoes. Earthquakes occur there due to the friction which is caused by the plates tearing apart.
Composite volcano
You get layers due to the rock at the top causing pressure and the magma pushes through. After many hours, the lava cools to form rock on the outside of the volcano. The ash from the eruption settles down on the outside and forms a new layer of rock. This is known as igneous rock. Therefore, the volcano is getting bigger.
Mercalli scale
Descriptive words for a scale
Seismometer
Instrument that measures the earthquake
Seismic
But of paper and pen. Pen moves when there is an earthquake. Paper moves.
Magnitude
The power of the earthquake
Liquefaction
Where water rises to the surface in clay, causing it to sink.
Andesite
Magma from the crust melting.
