CASCADIA SUBDUCTION ZONE (Syllabus: GS Paper 1 – Geography)

Context: The Cascadia Subduction Zone, considered one of Earth's top hazards, is gaining increased attention.

Cascadia Subduction Zone

• About: It is a 1,000 km long dipping fault that stretches from Northern Vancouver Island to Cape Mendocino California. It separates the Juan de Fuca and North America plates.
• Convergent Boundary: It is where the Juan de Fuca Plate subducts beneath the North American Plate, an active convergent boundary.
• Seismic Implications: This subduction process significantly impacts seismic activity in the region.
• Earthquake and Tsunami Risks:

oMassive Earthquakes: The CSZ can generate massive earthquakes, possibly reaching magnitude 9.0 or greater.

oTsunami Potential: These earthquakes can trigger tsunamis with heights exceeding 100 feet, posing significant risks to coastal areas.

oHistorical Precedent: A similar fault off Japan caused the devastating 2011 Fukushima nuclear disaster.

Subduction Zone

• Plate Collision: It occurs when two tectonic plates collide, with one plate subducting beneath the other.
• Tectonic Plate Movement: Tectonic plates are pieces of the Earth's rigid outer layer that slowly move across the planet's surface, driven by underlying forces.
• Plate Tectonics Theory: Subduction is a fundamental aspect of plate tectonics, where portions of Earth's shell move over the lower mantle, including continents.