Download ES 104 Midterm Exam Study Guide 1

ES 104 Midterm Exam Study Guide 2
Below is a list of materials to be familiar with. Also be sure to look over the in class
activities – especially the activity with the plate boundary diagram. Also look at the
handout about the Earth’s internal layers and the 2 types of crust.
Lectures 6 and 6b:
Earth’s Internal Structure
Compositional Layering – Crust, Mantle, Core
Layering based on physical properties – Lithosphere, Asthenosphere, Lower Mantle,
Outer Core, Inner Core
Be familiar with the general physical and compositional properties of the Earth’s layers.
Know that the lithosphere includes the crust and the upper most mantle rocks.
Know that the asthenosphere is solid but is soft and capable of gradual flow.
Know that the only layer that is completely molten is the outer core.
Know the differences between continental crust and oceanic crust (thickness,
composition, etc.)
Know why continentals are more elevated relative to the ocean floor.
Know that seismic waves are used to determine the properties of Earth’s interior.
The development of the Theory of Plate Tectonics
Be familiar with the hypothesis of Continental Drift and supporting evidence that the
continents were once combined as a single continent, Pangaea.
Be familiar with the Theory of Plate Tectonics – lithosphere is divided into plates that
move about on the soft, gradually flowing rocks of the asthenosphere.
Know that convection in the Earth’s mantle is the driving force of plate motion.
Three Types of Plate Boundaries – Be familiar with the plate motions that occur along each
of these.
Divergent boundaries – mid-ocean ridges and continental rifts
The formation of new lithosphere at mid-ocean ridges – sea floor spreading
Driving force at these boundaries – rising hot mantle – explains why ridges are
elevated above the surrounding seafloor.
Know that lithosphere gets thicker, colder and denser as it moves from the ridge.
Know that the record of Earth’s magnetic field is recorded in rocks
(paleomagnetism) and that it provides a record of seafloor spreading
Convergent boundaries – Subduction zones and continental collisions
The return of lithosphere to the mantle occurs along subduction zones.
Driving forces at these boundaries – sinking cold, dense lithosphere.
Know what volcanic arcs are and know that the Cascade Range is an example of
a continental volcanic arc.
Know what causes magma to form at subduction zones.
Know what The Ring of Fire is.
Surface expressions of subduction zones – oceanic trenches.
Examples of continental collisions – Himalayas and Alps.
Know that a subduction zone is offshore from the Pacific Northwest and that the
Cascade volcanoes are associated with this plate boundary.
Know that the largest magnitude earthquakes on record have occurred along
subduction zones.
Transform boundaries
Know that most transforms divide mid-ocean ridges into segments.
The San Andreas Fault in California is an example of a transform boundary in
continental crust.
Hotspots:
Know what a hotspot is and what causes hotspots (rising mantle plumes).
Know that many hotspots occur in the middle of tectonic plates.
Hawaii and Yellowstone are examples of volcanic features located on hotspots.
Know that the Hawaiian island chain formed as the Pacific Plate moved over a stationary
hotspot.
Lecture 7, 7b, and 7c:
Earthquakes:
Know the theory of elastic rebound – causes of earthquakes along faults
Know these terms: faults, hypocenter (focus), and epicenter
Know that most earthquakes occur along boundaries between tectonic plates
Know what types of motion are associated with P and S waves what materials each can
pass through.
Know that P waves are the fastest traveling seismic waves.
Be familiar with how the distance to an epicenter is determined – difference in arrival
times between p and s waves.
Know the difference between earthquake intensity and magnitude.
Know how an earthquake’s magnitude is determined on the Richter’s Scale.
Know that each number on the Richter’s scale corresponds with a 32-fold increase in
energy released during an earthquake.
Know how an earthquake’s moment magnitude is determined and what its advantage
over the Righter scale is.
Know how seismic waves reveal the physical characteristics of the earth’s internal layers
– example: S-waves cannot travel through the liquid outer core.
Earthquake damage and hazards
What factors determine the amount of damage that an earthquake can cause?
Know that steel-reinforced and wood-frame structures withstand earthquakes
better than unreinforced concrete and brick structures.
What is liquefaction?
Know that earthquakes can trigger destructive landslides.
What are Tsunamis and how are they formed?
What type of seafloor movement would result in a Tsunami wave?
Know that earthquakes along subduction zones can produce Tsunamis.
Earthquake Prediction
Know that presently, we cannot reliably predict the timing of an earthquake
within a narrow span of time (on a scale of months or less).
Know what long-range earthquake forecasts are and why they are useful.
Know that seismic gaps may indicate areas that could likely experience future
earthquakes.
Lecture 8:
Earthquakes in the Pacific Northwest
Be familiar with the sources of earthquakes in this region – the subduction zone,
crustal faults, and deep earthquakes in the subducted plate.
Know that the Cascadia Subduction Zone can produce very large earthquakes
with tsunamis.
Know that the last major Cascadia subduction zone earthquake occurred in the
year 1700.
Be familiar the forms of evidence that indicate that major subduction zone
earthquakes have occurred in the Pacific Northwest in the past.