The location of tectonic activity Identify, describe and explain the patterns of Earthquakes and Volcanoes
True or false? • Volcanoes and earthquakes happen all over the world. • Volcanoes are found in narrow belts. • Volcanoes are found along the East Coast of North and South America. • Volcanoes are found along the West Coast of North and South America.
Skills Builder 1 (a) Earthquakes occur in broad belts. Tend to be found in the middle of oceans e.g. Atlantic or along the edges of continents e.g. West coast of North America. Can also occur just off-shore of continental landmasses, e.g. western Pacific Ocean. There are some exceptions; there are earthquakes inland such as in eastern Africa. (b) Volcanoes also occur in broad belts. Found along the edges of continents e.g. West coast of South America. Can be found just off-shore of continental landmasses, e.g. western Pacific Ocean. Anomalies include cluster of volcanoes in the mid-Pacific around Hawaii and band of volcanoes inland in eastern Africa. N.B. Able students might note that earthquakes and volcanoes often occur in the same locations.
On the diagram, mark and name: the North American Plate, the Caribbean Plate, the Pacific Plate, the African Plate, the Eurasian Plate, the Arabian Plate, the Indo-Australian Plate. Check your answers using Figure 4 (student book p.101)
The structure of the Earth TASK 1 • Annotate (label) this diagram using the following words: Inner core Outer core Mantle Crust Plates Plate boundary
The Structure of the Earth FACTS • The inner core is the centre of the earth, made of solidiron and nickel, it is the hottest part with a temp. of 5500oC • The outer core is made up of liquid iron and nickel • The mantle is made up of semi-molten rock, partially melted rocks are called magma, temperatures reach 5000oC here. • The crust is the thinnest layer, and is made up of solid rock, it is the outer layer, like skin of an apple
Tectonic Plates • The Earth’s crust is divided up into plates • These plates ‘float’ or move very slowly (a few mm per year) on the molten material of the mantle. This movement is caused by convection currents in the mantle.
On the diagram below, mark and name: Inner core, Outer core, Mantle, Trench, Ridge. Check your answers using student book pp.101–102.
Plate tectonics • The place where two plates meet is called a plate boundary, most earthquakes and volcanoes happen here in a narrow belt called ‘zones of activity’
Add to you description b. Why do volcanoes and earthquakes happen in these locations
Neatly add these correct labels: Generally explosive volcanic eruptions. Magma rising to form volcanoes. Plate being forced into the mantle Deep, violent Earthquakes One plate is denser than the other so sinks. Plate melting.