The Restless Earth Flashcards

Question

What are the three Ps?

Answer 1

* **Prediction** - Attempt to forcecast event (where + when) based on current knowledge (e.g. USGS) * **Protection** - Constructing buildings so they are safe to stay in + will not collapse (e.g. Torre Major, Mexico City) * **Preparation** - Organising events + drills so people know what to do in the event of an emergency (e.g. FEMA)

Answer 2

The series of waves that hit the coast during a tsunami

Answer 3

Focus is the point **in** the crust where the pressure is released + the seismic waves come from Epicentre is the point **on** the crust directly about the focus. It recieves the highest amount of energy from the earthquake

Answer 4

Points on the crust where plumes of magma rise, weakening the crust They are away from plate boundaries

Answer 5

* **Newer** - less than 200 million years old * **Denser** than continental, can **subduct** * Can be **renewed + destroyed** * **Softer** + more malliable

Answer 6

* **Older** - over 1500 million years old * **Less dense**, cannot subduct * **Cannot** be **renewed + destroyed** * **Hard + brittle** - crumples to make fold mountains

Answer 7

Deep sections of the ocean created by an oceanic plate subducting underneath a continental one The Mariana Trench in the Pacific is the deepest place on Earth and is caused by two oceanic plates being subducted

Answer 8

A secondary effect of a volcanic event Ash mixes with rainwater or snowmelt to form huge mudflows than can travel up to 90mph

Answer 9

1. The **oceanic plate** is **subduted** beneath the continental plate as it is denser 2. As it moves into the mantle, it **melts** and forms **magma** and **gases** which force their way to the surface 3. This **magma and gas rises** and breaks through the continental plate, creating a vent and eventually forming a violent volcanic erruption 4. Volcanic bombs are created from the previous lava dome forced off by the pressure

Answer 10

* Formed at **destructive collision** boundaries where two continental plates collide. * **Sediment** is deposited on the ocean floor in **goecynclines**. * Over time it is **compressed** and forms **sedimentary rock** * As the two plates **collide**, the layers of rock are **forced upwards**, creating fold mountains * Minerals are also forced up during the collission

Answer 11

* Two oceanic plates move apart, **exposing magma** from the mantle which rises and reaches the ocean bed * It then **cools** and forms **rocks** and underwater **shield volcanoes** * As the plates continue to move apart over time, more magama is exposed and **builds up**, eventually reaching the **surface** of the sea * This then forms an **island** or a shield volcano on land

Answer 12

* Conservative boundaries occur where two plates slide past each other * **Friction** causes them to get **caught** on each other * Over time, **pressure** builds up until it is **suddenly released** and they jolt past each other * This is an **earthquake**

Answer 13

* Occur at **destructive subduction** boundaries * As the **oceanic** plate is **subducted** beneath the **continental** plate, it creates a deap **trench** * Part of the continental plate is also dragged under by the oceanic plate as subduction occurs * The deepest trenches (such as the Mariana Trench) are formed when oceanic-oceanic subduction occurs

Answer 14

* Occur at **destructive** boundaries * Magma builds up in **magma chamber** beneath the base. This is added to as oceanic crust melts as it subducts at the margin * As the magma rises through the **main vent**, it forms a **lava dome** as it very **viscous** (andersite) * Eventually, the **pressure** becomes too great and the dome is blown off in an **explosion** of ash, gas, lava, and debris * The **neck** of the volcano is **cleared**, allowing lava to flow out * As l**ava flows down the sides** of the volcano, it cools, **forming more layers + sides** of the volcano. **Ash settling** on the lava also causes the sides to build up

Answer 15

* Main vent * Secondary vent * Lava dome * Magma chamber * Volcanic bombs * Pyroclastic flows * Ash column * Layers of ash + lava forming steep sides * Crater * Steep sides, narrow base * Andersite lava (viscous)

Answer 16

* Summit caldera * Gentle, sloping sides * Magma chamber * Main vent * Layers of ash + lava forming sides * Flank eruption * Basalt lava (not very viscous)

Answer 17

A volcano that produces at least 1000km³ of material when it errupts

Answer 18

* **Caldera** - Depression/crater of the volcano marking the collapsed magma chamber * **Fissures** - Lines of weakness that allow magma to escape

Answer 19

* Supervolcanoes are found on **hotspots** * Yellowstone was created by a super erruption **640,000** years ago * Before the erruption, magma flowed into the magma chamber. * Too much **pressure** in the **magma chamber** caused **fissures** to form and **gas** and **ash** to be ejected out of them in a massive super erruption * After the erruption, the land **collpased** into the magma chamber, forming a **caldera**