Volcanoes and earthquakes flash cards.

Question	Answer
Conservative boundary	Plates slide past each other. Plates become locked and tension builds up. Rocks break and the plates jerk forwards. Powerful earthquakes occur but no volcanoes. For example the San Andreas fault.
Composite volcano	Occur on destructive boundaries. Violent eruptions with thick, sticky lava. Pyroclastic flows. Lahars - ash and rain. Tsunamis. Layers of ash and lava build up to form a cone. Ash leaves areas uninhabitable. For example Mount Etna and Soufrière Hills.
Shield volcanoes	Occur on constructive plate boundaries. Eruptions are not explosive. Thin, runny lava. Less loss of life. For example Iceland and Hawaii.
Constructive boundary	Two oceanic plates move apart. Magma rises due to gas bubbles in it. Volcanoes are formed. Gentle eruptions occur. Eruptions may continue for years. For example the Mid-Atlantic Ridge.
Destructive boundary	Oceanic and continental plates meet. The oceanic plate is pushed under the continental because it is heavier. It sinks into a subduction zone. Magma rises due to gas bubbles in it. Explosive eruptions occur. Plates rub leading to earthquakes. For example the Pacific Ring of Fire.
Collision boundary	Two continental plates meet. Plates buckle to form fold mountains. No volcanoes but violent earthquakes. For example the Himalayas.

Resource summary

	Created by my.denbow about 9 years ago