Continental Drift
Explain why Wegener’s contemporaries rejected continental drift despite strong geological and fossil evidence
Lack of a plausible mechanism for moving continents led to skepticism among geologists of the time.
What is the lithosphere composed of?
The lithosphere is composed of the crust and uppermost mantle.
What are the three three types of heat transfer. Explain
Conduction, Convection, Radiation
How do earthquake early warning systems detect and communicate imminent shaking?
They use seismic sensors to detect initial waves and send rapid alerts before damaging waves arrive.
A boundary marking a change in rock properties, such as composition or physical state, often recognized by changes in seismic wave speeds
Geological discontinuity
Name the hypothesis and scientist who modified Wegener's original idea to include two supercontinents, Laurasia and Gondwana.
The two-supercontinent hypothesis by Alexander L. Du Toit
Explain the role of the asthenosphere in plate tectonics.
The asthenosphere is a partially molten, plastic layer beneath the lithosphere that allows tectonic plates to move over it
How does the viscosity of mantle material affect convection current speed?
Higher viscosity slows convection currents, while lower viscosity allows faster mantle flow.
Name and describe the three main types of seismic waves produced during an earthquake.
P-waves (primary, compressional), S-waves (secondary, shear), and surface waves (Love and Rayleigh waves causing ground shaking)
How do seismic waves provide evidence for the existence of the Earth's liquid outer core?
S-waves do not travel through the outer core because it is liquid, creating a shadow zone that reveals its presence.
During which geologic period did Pangea begin to break apart, leading to the formation of modern continents?
Late Triassic Period
What are the three main types of plate boundaries, and what tectonic activity is characteristic for each?
Divergent (seafloor spreading and rifting), convergent (subduction and mountain building), transform (plates sliding past, causing earthquakes)
What is the primary heat source driving mantle convection currents?
Heat from Earth's interior, including residual heat from formation and radioactive decay
How do lahar flows differ from lava flows in volcanic hazards?
Lahars are fast-moving mudflows of volcanic debris mixed with water, highly destructive and different from slow-moving lava.
Explain the difference in behavior and mechanical properties between the lithosphere and the asthenosphere.
The lithosphere is rigid and brittle, making up the tectonic plates; the asthenosphere beneath is semi-fluid and ductile, allowing plate movement.
Which oceanic geological process discovered in the 1960s helped revive and support continental drift theory?
Seafloor spreading
How do mantle convection, slab pull, and ridge push contribute differently to plate motion?
Mantle convection circulates mantle material driving plates; slab pull pulls plates into subduction zones; ridge push forces plates away from mid-ocean ridges due to gravity
Describe how convection currents in the mantle relate to the movement of tectonic plates on the lithosphere.
Mantle convection currents create drag forces at the base of tectonic plates, driving their movement on the Earth's surface
Explain the hazards and consequences of pyroclastic flows during volcanic eruptions.
Fast-moving hot gas and volcanic ash flows that can destroy everything in their path, cause burns, suffocation, and mass destruction
It is the boundary between the mantle and the outer core, marked by the change from solid to liquid, affecting seismic wave behavior.
Gutenberg Discontinuity
Describe the geological and paleomagnetic evidence that supports seafloor spreading as a mechanism for continental drift.
Symmetrical patterns of magnetic striping on ocean floors and age progression of oceanic crust away from mid-ocean ridges
What is the significance of the Ring of Fire in plate tectonics?
It is a major area of frequent earthquakes and volcanic eruptions due to multiple plate boundaries around the Pacific Ocean.
Describe how subduction zones contribute to the recycling of oceanic crust.
Oceanic crust sinks back into the mantle at subduction zones, where it melts and is recycled.
What monitoring techniques and early warning signs do volcanologists use to predict potential eruptions? Give all five(5).
Seismic activity, ground deformation, gas emissions, temperature changes, and satellite imagery
How do seismic wave velocity changes help identify and characterize Earth's internal discontinuities?
Changes in seismic wave speeds and their refracted or reflected paths at discontinuities indicate differences in composition, density, and state (solid/liquid), helping map Earth's internal layering.