Mount Rainier is a young volcano, huge and high. Its fires are far from quenched: its glaciers are an awesome store of perched frozen water. This combination makes it the most dangerous volcano in America. Built high astride intersecting ridges and canyons of Washington's central Cascades, Rainier supports the largest single peak glacier system in the forty-eight adjacent states.
Rainier belongs to a chain of fifteen recently active volcanoes stretched between Mount Garibaldi, in southern British Columbia and Mount Lassen in northern California called the Pacific Ring of Fire, (or sometimes just the Ring of Fire) It is an area where large numbers of earthquakes and volcanic eruptions occur in the basin of the Pacific Ocean. Located in a horseshoe shape, it is associated with a nearly continuous series of oceanic trenches, volcanic arcs, and volcanic belts and/or plate movements. The Ring of Fire is believed to be a direct result of plate tectonics and the movement and collisions of crustal plates . Of the volcanoes located in the Pacific Ring of Fire , Rainier is the tallest and most imposing. It is a composite volcano made from sluggish, intermittent lava flows and explosive eruptions of ash and rock.
Volcanoes are not randomly distributed over the Earth's surface. Most are concentrated on the edges of continents, along island chains, or beneath the sea forming long mountain ranges. More than half of the world's active volcanoes above sea level encircle the Pacific Ocean to form the circum-Pacific "Ring of Fire." In the past 25 years, scientists have developed a theory, called plate tectonics, or subduction, that explains the locations of volcanoes and their relationship to other large-scale geologic features. About 90% of the world's earthquakes and 80% of the world's largest earthquakes occur along the Ring of Fire. Mount Rainier was believed to be formed from plate tectonics in an area called the Cascadia Subduction Zone. It is a very long sloping fault that stretches from mid-Vancouver Island to Northern California. New ocean floor is being created offshore of Washington and Oregon. As more material wells up along the ocean ridge, the ocean floor is pushed toward and beneath the continent. The Cascadian Subduction Zone is where the two plates meet.
Unlike most subduction zones worldwide, there is no oceanic trench present along the continental margin in the Cascadia subduction zone. Instead, terranes and the accretionary wedge have been uplifted to form a series of coastal ranges and exotic mountains. However, in common with most other subduction zones, the outer margin is slowly being compressed, similar to a giant spring. When the stored energy is suddenly released by slippage across the fault at irregular intervals, the Cascadia subduction zone can create very large earthquakes such as the magnitude 9 Cascadia earthquake of 1700. It impacted the area mid-Vancouver Island in British Columbia, Canada, south along the Pacific Northwest coast and as far as northern California. There is also evidence of accompanying tsunamis with every earthquake, and one line of evidence for these earthquakes is tsunami damage. The earthcache, Puget Sound Tsunami, GC2AZ59 explores the evidence of one such tsunami that hit Whidbey Island in the past.
To qualify as a "find", email (do not post online) the answers to the following questions.Failure to do that in a timely manner will result in a log deletion.
Visit the interpretive sign at the posted coordinates and answer the following questions:
1) What are the names of the two plates that form the process of subduction here?
2) On a clear day, what are the maximum amount of Cascade volcanoes one may observe here and what are their names?
3) On the day of your visit, how many of those volcanoes from the Ring of Fire were evident?
Please upload two photos of yourself , if possible. One with the nearby interpretive signs, yourself and your GPSr and one with the Lord of the Ring, Mount Rainier, taken anywhere in the National Park. Please attach them to your found log. ( Be sure to not give away any of the answers!)
Due to seasonal limitations this earthcache is only available during the warmer months, generally July through early September, when the road to Sunrise is open to the public. The following link may prove to be helpful on planning your visit. We hope you have learned a thing or two about Rainier and the Ring of Fire. Thanks for visiting Mount Rainier National Park!
Warning: Earthcaches come with a unique set of rules and activities that must be met
before successfully logging. Failure to comply will result in a log deletion.