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Year 9 Geology
Science, Term 4, Geology
Question | Answer |
---|---|
What is the structure of the Earth? | There is a thin crust, approximately 10-100km thick. Underneath that, is the Mantle, which has the properties of a solid but it can also flow. Next, is the core, with is made of molten nickel and iron. The outer part is liquid, the inner part is solid. |
What is the Earth's Crust motion? | Convection currents |
What are diverging boundaries? | The tectonic plates move away from each other. Convection currents create more of Earth's surface. Magma is rising, so the Earth's surface is growing. |
What are subduction converging boundaries? | A subduction zone occurs when you get and more dense plate and a less dense plate and it slips underneath. |
What are collision converging boundaries? | Collision happens when the plates are the same density, and two continental plates push up to form a mountain. |
What are transform boundaries? | Transform boundaries are two plates that are moving in a horizontal direction in opposite directions. |
Name the three types of plate boundary. | Diverging, Converging and Transform. |
Name the two types of crust that form the tectonic plates. | Oceanic and continental. |
Describe the process of subduction. | One plate moves under another and is forced down into the mantle. Regions where this process occurs are known as subduction zones. |
What was the super continent called? | The super continent was called Pangaea. |
Who discovered the supercontinent's existence? | Alfred Wegener discovered Pangaea. |
How did Alfred Wegener discover Pangaea's existence? | He noticed that the continents fit together like a jigsaw puzzle. He also noticed that along with plant species, he found animal fossils on different continents. |
What is the definition of a volcano? | A volcano is a place where extremely hot material form inside the Earth erupts at the Earth's surface. This material includes; gas such as steam and hydrogen sulfide, ash (fine particles of rock, lava (molten rock) and lumps of solid volcanic rock. |
How do volcanoes form? | Volcanoes form where there are weak spots int he Earth's crust and where extremely hot molten rock called magma has accumulated below the weak spots. This magma is occasionally pushed upwards under great pressure into the volcano. |
What is an earthquake? | An earthquake is the rapid movement of the ground, usually back and forth and up and down in a wave motion. It is caused by the rapid release of energy as the tectonic plates move. |
How are earthquakes detected? | Earthquakes are measured using an instrument called a seismometer. |
What are P-waves? | Primary waves (P-waves) are longitudinal waves that travel fast through the Earth. |
What are S-waves? | Secondary waves (S-waves) are transverse waves that travel slightly slower than P-waves through the Earth. |
What waves cause the most damage.? | Surface waves are the slowest waves and cause the most destruction. |
What is the difference between the epicentre and hypocentre? | The epicentre is the point on a planet's surface that is directly above the hypocentre, which is also called the focus of an earthquake. The hypocentre is the starting point of fracturing rocks, and it is the actual point where earthquakes begin. |