Volcanic Hazards and Effects

The video discusses various volcanic hazards, focusing on composite and shield volcanoes. It covers the Cascade Range's eruption history, tephra's economic impact, lahars' formation and dangers, and the destructive power of pyroclastic flows. Lava flows are also examined, highlighting their characteristics and environmental impact. The lesson concludes with a learning objective to understand these hazards.

Which cities are located near the Cascade Range, making them vulnerable to volcanic hazards?

• Portland, Seattle, and Vancouver

• Los Angeles, San Francisco, and San Diego

• New York, Boston, and Philadelphia

• Miami, Orlando, and Tampa

What is tephra primarily composed of?

• Water and mud

• Rock fragments and particles

• Toxic gases

• Molten lava

How can tephra affect transportation?

• By causing landslides

• By blocking roads and making surfaces slippery

• By flooding areas

• By creating sinkholes

What triggers the formation of lahars?

• Tsunamis

• Earthquakes

• Heavy rainfall or melting ice mixing with volcanic deposits

• Volcanic eruptions

Which volcanic event led to the destruction of the town of Armero in Colombia?

• A lava flow

• An earthquake

• A pyroclastic flow

• A lahar

What makes pyroclastic flows particularly dangerous?

• Their slow movement

• Their high temperature and speed

• Their ability to cause tsunamis

• Their tendency to form lava domes

Where did the deadliest pyroclastic flow in the last century occur?

• Iceland

• Hawaii

• Mount Saint Helens

• Martinique

What is a characteristic of lava from composite volcanoes?

• It flows quickly over long distances

• It forms wide volcanic shapes

• It is sticky and viscous, not traveling far

• It is primarily composed of water

How do lava flows from shield volcanoes differ from those of composite volcanoes?

• They are more likely to form pyroclastic flows

• They are more explosive

• They are more fluid and travel greater distances

• They are cooler in temperature

Why are lava flows considered one of the least deadly volcanic hazards?

• They are easy to predict

• They move slowly, allowing people to evacuate

• They only occur in uninhabited areas

• They are always contained within the volcano