dynamic earth Flashcards
What is the focus of an earthquake?
The focus is where the earthquake first starts underground.
What is the epicenter of an earthquake?
The epicenter is the point directly above the focus on the Earth’s surface.
What does a seismograph measure?
A seismograph measures the magnitude and strength of an earthquake.
What is the difference between the Richter scale and the Moment Magnitude Scale?
The Richter Scale only measures the magnitude of an earthquake.
The Moment Magnitude Scale (Mw) measures both magnitude and the type of earthquake (energy released).
What is a tsunami?
A tsunami is a massive wave caused by an earthquake that can travel up to 800 km/h.
What are the three types of plate boundaries?
Divergent, Convergent, and Transform.
What happens at a divergent boundary?
Tectonic plates move away from each other.
What happens at a convergent boundary?
Tectonic plates push against each other.
What happens at a transform boundary?
Tectonic plates slide past each other.
What are convection currents?
Circular movements of magma in the mantle that cause tectonic plates to move.
What is continental drift theory?
Alfred Wegener’s theory that continents were once joined (Pangaea) and slowly drifted apart.
What is the rock cycle?
A cycle where rocks change into different types (igneous, sedimentary, metamorphic) over time.
What are intrusive and extrusive igneous rocks?
Intrusive: Form inside the Earth, cool slowly, have large crystals (e.g., granite).
Extrusive: Form outside the Earth, cool quickly, have small crystals (e.g., basalt).
How does an igneous rock become a sedimentary rock?
Through weathering, erosion, compaction, and cementation.
How does a sedimentary rock become a metamorphic rock?
Heat and pressure applied over time.
What is a hotspot?
A place where hot magma rises from deep in the mantle, creating volcanoes away from plate boundaries (e.g., Hawaiian Islands).
What are the three main types of seismic waves?
P-waves: Fast, travel through solids & liquids, push-pull motion.
S-waves: Slower, travel only through solids, side-to-side motion.
Surface waves: Slowest but most destructive, rolling motion.
What is a fault in geology?
A crack in the Earth’s crust where tectonic plates move, causing earthquakes.
What is liquefaction, and why is it dangerous?
When wet soil acts like a liquid during an earthquake, causing buildings to sink or collapse.
What is the difference between the lithosphere and the asthenosphere?
Lithosphere: The rigid outer layer of the Earth, made up of the crust and upper mantle.
Asthenosphere: A partially molten layer beneath the lithosphere where convection currents occur, causing plate movement.
What are the layers of the Earth?
Crust – The thin, outermost layer (made of continental & oceanic crust).
Mantle – Thickest layer, made of semi-molten rock (magma).
Outer core – Made of liquid iron and nickel, responsible for Earth’s magnetic field.
Inner core – Solid iron and nickel, extremely hot and under high pressure.
What is subduction, and where does it occur?
Subduction is when a denser oceanic plate sinks beneath a less dense continental plate at a convergent boundary.
It occurs at oceanic-continental and oceanic-oceanic boundaries, forming deep trenches and volcanoes.
Example: The Pacific Ring of Fire.
What are the four main types of volcanoes?
Shield Volcano – Broad, gently sloping, formed by runny lava (e.g., Mauna Loa, Hawaii).
Stratovolcano (Composite Volcano) – Steep, explosive, formed by layers of lava and ash (e.g., Mount St. Helens).
Cinder Cone Volcano – Small, steep-sided, made of volcanic debris (e.g., Paricutin, Mexico).
Supervolcano – Huge eruptions, caldera-forming, can cause global climate effects (e.g., Yellowstone).
What is the Ring of Fire?
A major zone of earthquakes and volcanoes around the Pacific Ocean.
Caused by subduction zones where oceanic plates sink beneath continental plates.
