Oregon Why is there a green side and a brown side of Oregon? Corvallis

Oregon Cascades Coast Range Willamette Valley Why are there Two Parallel Mountain Ranges in Oregon?

National Aeronautics and Space Administration The Whole Earth and Plate Tectonics We need to understand know what goes on inside the Earth.

Depths in Miles

Oreo ® Cookie

Robert J. Lillie

Oreo ® Psycho-Personality Test Psychologists have discovered that the manner in which people eat Oreo ® cookies provides great insight into their personalities. Choose which method best describes your favorite method of eating Oreos: 1. The whole thing at once. 2. One bite at a time. 3. Slow and methodical nibbles examining the results of each bite afterwards. 4. In little feverous nibbles. 5. Dunked in some liquid (milk, coffee …..) 6. Twisted apart, the inside, then the cookie. 7. Twisted apart, the inside, and toss the cookie. 8. Just the cookie, not the inside. 9. I just like to lick them, not eat them. 10. I don’t have a favorite way because I don’t like Oreos.

6. Twisted apart, the inside, then the cookie. You have a highly curious nature. You take pleasure in breaking things apart to find out how they work, though you’re not always able to put them back together, so you destroy all the evidence of your activities. You deny your involvement when things go wrong. You are a compulsive liar and exhibit deviant, if not criminal, behavior.

Robert J. Lillie Parks and Plates, ©2005 Robert J. Lillie Sliding Plate over Asthenosphere

Robert J. Lillie Divergent Plate Boundary Parks and Plates ©2005 Robert J. Lillie North America Africa Atlantic Ocean

National Geographic Mid-Atlantic Ridge (Divergent Plate Boundary) North America Africa Iceland

Pillow Basalt

Africa South America Core Lower Mantle Atlantic Ocean Asthenosphere Lithosphere Trench Divergent Plate Boundary: New Lithosphere Created Mid-Atlantic Ridge Convergent Plate Boundary: Lithosphere Recycled back into Deeper Mantle Modified from Hamblin and Christiansen, 2001 New lithosphere created at divergent plate boundaries. Does that mean Earth is expanding?

Robert J. Lillie Convergent Plate Boundary Parks and Plates ©2005 Robert J. Lillie Subducting Plate Overriding Plate Deep-Sea Trench

Coast Range Cascades Subduction of the Juan de Fuca Plate forms the Coastal Ranges and Cascade Volcanoes

Robert J. Lillie Bernard Garcia Formation of the two parallel mountain ranges.

Robert J. Lillie Bernard Garcia Sedimentary layers scraped off the subducting plate form the Coast Range.

Mary’s Peak Corvallis, Oregon Oregon State University

Mary’s Peak Pillow Basalt – Coast Range Rocks made in the Ocean!

Robert J. Lillie Bernard Garcia Just like when you bicycle, the subducting plate sweats when it gets hot

Robert J. Lillie Bernard Garcia The rising hot water melts rock in its path, forming magma.

Robert J. Lillie Bernard Garcia Mount Hood and other Cascade Volcanoes form where some of the magma reaches the surface.

Robert J. Lillie Bernard Garcia Puget Sound and the Willamette Valley are low-lying regions between the rising mountains.

U. S. Geological Survey Mt. St. Helens, Washington Prior to 1980 Steep Composite Volcano

U. S. Geological Survey Early 1980 Bulge on North Side of Mountain Mt. St. Helens, Washington

U. S. Geological Survey May 18, 1980 Explosive Eruption Mt. St. Helens, Washington

U. S. Geological Survey May 18, 1980 Mt. St. Helens, Washington Eruption Cloud

Robert J. Lillie Mt. St. Helens National Volcanic Monument, Washington foot Douglas Fir trees downed on north side of mountain

U. S. Geological Survey Mt. St. Helens National Volcanic Monument, Washington

Paul Rockwood 7,700 years ago – Southern Oregon’s Mt. Mazama was perhaps taller than Mt. Hood.

Paul Rockwood Vast amounts of volcanic ash, pumice, and lava flows erupted – the top of the mountain collapsed as rubble to fill the void, creating a large crater.

Robert J. Lillie No rivers or creeks flow in or out of Mt. Mazama’s crater – rainfall and snowmelt partially fill it with some of the purest and clearest water in the world Crater Lake – 1,943 feet (592 meters) – deepest in the United States and 7 th deepest in the world!

M. Williams, National Park Service Later eruptions coated the crater floor – just like at Aniakchak Volcano in Alaska! Volcano Inside a Volcano Lava Flows Aniakchak National Monument, Alaska

U. S. Geological Survey U.S. Geological Survey 3-D Image of Lake Bottom Lava flows seal the bottom of Crater Lake Volcano Inside a Volcano Lava Flows Wizard Island Merriam Cone Crater Lake Fly- Through Movie Time: 0:57

Robert J. Lillie Wizard Island is a Cinder Cone Volcano formed after Mt. Mazama collapsed Wizard Island

Oregon Cascade Volcanoes Coast Range Willamette Valley The Two Parallel Mountain Ranges make the green and brown sides of Oregon

There are 20 potentially active volcanoes in the western United States (excluding Alaska and Hawaii). Half are in the Cascades of Washington, Oregon, and northern California.

Cracked Egg Shell! Parks and Plates ©2005 Robert J. Lillie

Parks and Plates ©2005 Robert J. Lillie Plate Boundaries San Andreas Fault Western California is a Transform Plate Boundary

Robert J. Lillie Transform Plate Boundary Parks and Plates ©2005 Robert J. Lillie Pacific Plate North American Plate San Andreas Fault

Robert J. Lillie Parks and Plates ©2005 Robert J. Lillie Creating the SAN ANDREAS FAULT with a Deck of Cards Pretend your left hand is the Pacific Plate, your right hand the North American Plate.

Robert J. Lillie Parks and Plates ©2005 Robert J. Lillie Creating the SAN ANDREAS FAULT with a Deck of Cards The TRANSFORM PLATE BOUNDARY is a broad zone of shearing between the two plates.

Robert J. Lillie Parks and Plates ©2005 Robert J. Lillie Creating the SAN ANDREAS FAULT with a Deck of Cards One card face eventually takes over, simulating the predominance of movement along the San Andreas Fault.

North American Plate Pacific Plate 2 inches/year x 100 years = 200 inches = 17 feet! So in 100 years, a total of 17 feet (5 meters) of movement would occur across the fault! Orange Grove in Southern California – Planted 100 Years Ago

Marshak, EARTH (Norton, 2005) Parks and Plates ©2005 Robert J. Lillie The San Andreas Fault and Gulf of California accommodate transform plate motion between the North American and Pacific plates. The San Andreas Fault accommodates most of the transform plate motion in California.

California Earthquake 1973

Earthquakes Parks and Plates ©2005 Robert J. Lillie Most earthquakes are at plate boundaries.

Parks and Plates ©2005 Robert J. Lillie Plate Boundaries

Where are the Volcanoes? 70% of them are in the "Ring of Fire" Earth has more than 1500 active volcanoes Turcotte, 1971

Plate Boundaries

Robert J. Lillie Bernard Garcia 1. Where do Big Earthquakes occur? Cascadia Subduction Zone 2. Why do they occur there? Plates stick together for about 300 years, then suddenly let go! Boom!!!!

Parks and Plates ©2005 Robert J. Lillie Locked Zone Earthquake in the Pacific Northwest

Parks and Plates ©2005 Robert J. Lillie Locked Zone Earthquake in the Pacific Northwest

U.S.G.S. What drowned these trees 300 years ago?

Earthquakes from under the seas Cause big waves to submerge the trees The first waves are small Compared to them all These waves we call – tsunamis These waves we call – tsunamis! Generation of a Tsunami

We can see what’s on the surface. Cascadia Subduction Zone How does the surface change when the plates are stuck? How do we really know what’s beneath here?

Drillhole across San Andreas Fault 875 GPS Instruments 175 Borehole Strainmeters 5 Long-Baseline Laser Strainmeters 400 Seismometers at 2,000 sites 100 Permanent Seismometers A project to: – Explore the structure and evolution of the North American continent – Understand processes that cause earthquakes and volcanic eruptions. EarthScope

Robert J. Lillie