REVIEW PART 2

Which statement is accurate based on the figure displaying global earthquake distribution, where white lines indicate plate boundaries?

• • Earthquakes exclusively happen along plate boundaries.

• • Earthquakes are most commonly found along plate boundaries.

• • Earthquakes seldom take place along plate boundaries.

• Earthquakes do not occur along plate boundaries.

A normal fault forms when forces push two blocks of rock away from each other. At which type of plate boundary does this happen, and why?

• • Convergent plate boundary – Plates move toward each other.

• • Convergent plate boundary – Plates move apart.

• • Divergent plate boundary – Plates move apart.

• • Divergent plate boundary – Plates move toward each other.

Which statement correctly describes a pyroclastic flow?

• • Pyroclastic flows travel faster than 100 km/hr and reach temperatures above 2,000°C.

• • Pyroclastic flows form when melted snow and ice mix with ash and mud on the mountain.

• • Pyroclastic flows move slowly and are rarely dangerous.

• • Pyroclastic flows move rapidly but remain relatively cool.

What movement between two blocks of rock along a fault triggers an earthquake?

• • Sliding past each other horizontally

• • Moving toward each other

• • Pulling apart from each other

• • Any of the above

What is the average number of volcanoes that erupt each year?

(a)  

On the moment magnitude scale, each step represents 31.5 times more energy release. Approximately how much more motion does a magnitude 7 earthquake have compared to a magnitude 4 earthquake?

• • 90 times

• • 900 times

• • 27,000 times

• • 3,000 times

Lava flows, such as the one from Mount Etna

• • Can last for more than six months.

• • Move rapidly and result in many deaths.

• • Seldom cause any damage.

• • Never lead to town evacuations.

What best describes the composition of volcanic ash?

• • Particles of pulverized rock and vegetation

• • Pulverized bits of glass

• • Pulverized particles of rock

• • Particles of pulverized rock and glass

How does rising mantle material at mid-ocean ridges contribute to ridge push?

• • It forces plates to move toward the ridge.

• • It generates pressure, pushing plates away from the ridge.

• • It produces new crust that later sinks into the mantle.

• • It cools and shifts plates vertically.

How do convection currents in the asthenosphere contribute to plate movement?

• • They generate heat that pushes plates apart.

• • A material, dragging the lithosphere like a conveyor belt.

• • They cool the mantle, causing plates to sink.

• • They cause volcanic eruptions that move the plates.