Volcanoes monitoring
True or false: ash coming out of Mount St. Helens in 1980 is a type of lava?
True!
What is a types of scientific evidence that the Earth’s crust has moved over time?
the matching shape of the continents & ability for the continents to fit together like puzzle pieces
by matching fossils in different continents that give evidence that habitat for life was similar in the past in places today that are very different
What type of plate tectonic boundary causes the uplift of the Himalayan mountains?
convergent: continent to continent
What element makes up > 80% of the center of the earth in the earth's inner core?
What is often the first gas that often comes up out of volcanoes that can be a clue about how the magma is moving underground?
carbon dioxide
What is the name of the fossil hunter from Europe who played a major role in discovering important fossils to teach about the history of the earth?
Mary Anning
What is a mid-ocean ridge?
a chain of volcanoes that runs through our oceans
What type of volcanoes produce the most volume of lava?
hot spot volcanoes! source deep in the earth
What type of plate boundary forms the most explosive volcanoes?
convergent - subduction
How often do volcanoes in the Cascades Volcanic range in the Pacific Northwest erupt on average?
1-2 times every 100 years
On average, what is the speed that most tectonic plates move on the surface of the earth?
at the rate of fingernail growth (1-4 centimeters/year or 0.5-1.5 inches/year)
What tool helped scientists discover the topography (shape) of the ocean floor?
sonar: sending sound waves underwater off of ships to bounce along the ocean floor
When pieces of subducting oceanic crust sink into the mantle, pieces of crust tend to accumulate in a specific layer inside the earth. What is the name for this layer?
the plate graveyard!
Why are continental shelves important habitats on our present planet?
continental shelves are areas of more shallow water that are rich with nutrients and sunlight. 90% of the world's fish live along continental shelves!
What makes volcanic ash so dangerous?
volcanic ash is tiny fragments of volcanic rock and are very sharp (abrasive)
volcanic ash can travel very far distances
volcanic ash when mixed with water turns into the consistency of wet cement
What is the fastest speed that some tectonic plates move on the surface of the earth?
at the rate of hair growth (9-16 centimeters/year or 3.5 - 9 inches/year)
What is an example on our present earth where we have a hot spot volcano?
Hawaii! Yellowstone!
Which layer of the core of the earth is moving (convecting) to cycle heat: the inner core or the outer core?
the outer core
What are the names of three plates in our region? Draw a diagram on the board in map view!
Juan de fuca - oceanic plate
Pacific - oceanic plate
North America - continental plate
What are three ways that scientists today monitor signs that a volcano is becoming active (waking up?
1. monitoring gases
2. ground deformation
3. earthquakes
What are some reasons why scientists believe Mars does not have actively moving plates on its surface?
Mars is smaller than planet earth and cooled more quickly. The crust is now probably too thick and hard to move as plates
There are no oceans on the surface of Mars
Scientists have not found any places on Mars where new crust is forming (such as at a divergent plate boundary) or where crust is being recycled (such as convergent plate boundary)
there is no evidence from the rock record that large pieces of Mars’ crust moved over time and created landforms such as volcanic chains or mountains
In subduction zone volcanoes such as Mount St. Helens in the Pacific Northwest, what causes the crust to melt?
adding water from the subducting plate
What two elements make minerals in rocks from deeper in the earth's crust dark colored?
Fe - ireon
Mg - magnesium
Since the time of the dinosaurs in our region of the Pacific Northwest (the past 85 million years) what type of plate boundary has created the majority of volcanoes and mountains in our region?