Cascades Volcanoes Overview Quiz
Where Cascade volcanoes sit; primary hazards by type (10 questions).
Cascades Volcanoes Overview Quiz: Quick Study Notes
The Cascade Volcanic Arc is a major mountain range in Western North America, famous for its majestic, and often active, volcanoes. Stretching from British Columbia to northern California, these peaks are part of the ‘Ring of Fire’ and are a result of oceanic plate subduction. Understanding their location and the hazards they pose is crucial for residents and disaster preparedness in the Pacific Northwest.
Key Concepts
Stretching from southern British Columbia through Washington and Oregon to northern California.
Formed by the subduction of the Juan de Fuca, Gorda, and Explorer Plates beneath the North American Plate.
Predominantly stratovolcanoes (composite volcanoes), characterized by their steep slopes and explosive eruptions.
Pyroclastic flows, lahars, ashfall, lava flows, and volcanic gases.
Key Takeaways
- The Cascade Volcanic Arc is part of the Pacific Ring of Fire, a zone of frequent earthquakes and volcanic eruptions.
- It extends approximately 1,200 kilometers (750 miles) through southwestern British Columbia, Washington, Oregon, and northern California.
- Most Cascade volcanoes are stratovolcanoes, known for their potentially explosive eruptions and high viscosity magma.
- Their formation is a direct result of the subduction of the Juan de Fuca, Gorda, and Explorer oceanic plates under the North American Plate.
- Primary hazards include fast-moving pyroclastic flows, destructive lahars (volcanic mudflows), and widespread ashfall which can disrupt infrastructure.
- Mount St. Helens’ 1980 eruption serves as a significant case study for Cascade volcano hazards and monitoring.
- Volcanic gases and less common lava flows also pose localized threats near the vents.
Frequently Asked Questions
Where are the Cascade volcanoes located?
The Cascade volcanoes stretch from southwestern British Columbia, Canada, through the U.S. states of Washington and Oregon, and into northern California, USA.
What type of volcanoes are most common in the Cascades?
The majority of major Cascade volcanoes are stratovolcanoes, also known as composite volcanoes. These are characterized by their steep, conical shape and explosive eruptions.
What causes the Cascade volcanoes to form?
They are formed by the subduction of the Juan de Fuca, Gorda, and Explorer oceanic plates beneath the North American continental plate, a process that creates magma and volcanic activity.
What are the primary hazards associated with Cascade volcanoes?
Key hazards include pyroclastic flows (fast-moving hot gas and debris), lahars (volcanic mudflows), widespread ashfall, lava flows, and the release of volcanic gases.
Which Cascade volcano is famous for its 1980 eruption?
Mount St. Helens in Washington State is renowned for its catastrophic eruption on May 18, 1980, which included a massive lateral blast and debris avalanche.
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