Subduction Zones and Earthquake Dynamics

The video discusses subduction, a key concept in plate tectonics, focusing on the Cascadia subduction zone. It explains how oceanic and continental plates interact, leading to geological phenomena like spreading zones, accretionary wedges, and subduction zones. The video also covers the formation of volcanoes and the occurrence of megathrust earthquakes, particularly in the Pacific Northwest. The importance of understanding these processes is highlighted, with examples of significant earthquakes and volcanic activity.

What is the primary focus of the Cascadia subduction zone discussed in the video?

• The formation of new oceanic crust

• The hazards it poses to the Pacific Northwest

• The creation of mountain ranges

• The development of deep-sea trenches

What type of crust is typically formed at spreading zones?

• New oceanic crust

• Old continental crust

• New continental crust

• Old oceanic crust

What happens to oceanic crust when it meets continental crust at a subduction zone?

• It rises above the continental crust

• It remains stationary

• It subducts below the continental crust

• It forms a new spreading zone

What is an accretionary wedge?

• A layer of sediment scraped off at a subduction zone

• A type of earthquake fault

• A type of volcanic rock

• A new oceanic crust formation

What geological feature is commonly found near subduction zones?

• Rivers

• Volcanoes

• Deserts

• Glaciers

How does water affect the melting point of rocks in subduction zones?

• It solidifies the rocks

• It lowers the melting point

• It has no effect

• It raises the melting point

What is a megathrust earthquake?

• An earthquake that occurs in the middle of a tectonic plate

• An earthquake caused by volcanic activity

• A minor earthquake with little impact

• A powerful earthquake at a subduction zone

What natural disaster is often triggered by megathrust earthquakes?

• Tornadoes

• Tsunamis

• Floods

• Hurricanes

Which region is known for its megathrust earthquakes?

• The Pacific Northwest

• The Sahara Desert

• The Amazon Rainforest

• The Great Plains

What was the magnitude of the 2011 Tohoku earthquake in Japan?

• Over 9.0

• Between 8.0 and 9.0

• Between 7.0 and 8.0

• Below 7.0