Test 3 (Lectures 9-12) Pt. 1 Flashcards
Why are volcanic areas a good area to live in?
They make really fertile soil, which in turn produces good crops
What 4 primary settings do volcanic activity occur in?
- Isolated hot spots/mantle plumes
- Volcanic arcs bordering deep ocean trenches
- Mid-ocean ridges (divergent plate boundaries)
- Continental rifts (divergent plate boundaries)
Where are volcanoes mainly located in Earth?
They are mainly found in:
- Plate boundaries (more specifically the Pacific Ocean boundary)
- Subduction zones
What is the name of the region where volcanoes are mainly found in?
Ring of Fire
When mantle plumes break out in the surface they create…?
Large Igneous Provinces
Hot spots are always…
Stationary
What type of lava flows out more easily?
Mafic
Which volcano would have mafic lava that flows easily and spreads out?
Shield volcanoes
Which volcano has felsic lavas?
Stratovolcanoes made up of rhyolite
Shield volcanoes are made up of…?
Basalt
What type of rock releases more gas?
Mafic
Stratovolcanoes are more ____-rich?
Felsic
Shield volcanoes are more ___-rich?
Mafic
How is a caldera formed?
When the magma chamber collapses forming a gigantic volcanic depression
Lava domes are referred to as…
Resurgent domes
Smaller volcanoes are referred to as…
Cinder cones/scoria cones
Falling ash is referred to as..
Tephra
What are pyroclastic flows?
Superheated clouds of gas, ash, and debris
Lahars is a combination of …
Mud, ash, water, etc
Earthquakes tend to occur more in a ____ zone
Fault
Most earthquakes are caused by…
Tectonic plates interacting with each other in a fault zone
We know the layers of the Earth through….
Seismic activity
What are faults?
Displacements of the ground
What is an epicenter?
Point of the surface where the earthquake occurred
What is the focus/hypocenter?
Area where the earthquake occurred underground
What are the two main groups of seismic waves?
- Body waves
- Surface waves
What type of waves are faster? Body or surface waves?
Body waves
What type of waves are considered more destructive? Body or surface waves?
Surface waves
What are the two different types of body waves?
- Primary (P) waves
- Secondary/Shear (S) waves
What is the flow of motion for P-waves?
They move by compressing and expanding back and forth
What states of matter can P-waves flow through?
Solids, liquids, and gases
What is the flow of motion for S-waves?
They travel by moving materials up and down like a rollercoaster
What states of matter can S-waves travel through?
They can travel through solids but never liquids and gases
What are the two different surface waves?
- Love (L) waves
- Raleigh (R) waves
Which wave comes first? Love or Raleigh?
Love waves
What is the flow of motion for Love waves?
They move side to side like a slithering snake
What is the flow of motion for Raleigh waves?
They have a rotating motion
What type of waves are more destructive?
Surface waves
What instrument do we use to measure Earthquakes?
Seismometer
What does a seismometer do?
It records ground motion and it measures wave arrivals and then the magnitude of each motion
How many stations are needed to pinpoint the epicenter?
3 or more stations
Earthquake size is described by two different measurements, what are they?
- Intensity - The severity of the damage
- Magnitude - The amount of energy released by the earthquake
What does the Mercalli intensity scale measure?
- It measures the amount of shaking damage. They have Roman numerals to measure the damage. The scale is subjective because it’s based on opinions.
What do shaking and damage of an earthquake depend on?
- The magnitude of the earthquake
- Distance of the focus
- Nature of subsurface material
- Bedrock has less damage
- Sediments have more amplified damage
Can we predict earthquakes?
Both yes and no. For yes, they can be predicted in the long term. For no, they can’t be predicted for the short term.
What human activities can cause Earthquakes?
Deep Waste Disposal
Nuclear/ Bomb Explosions
What kind of fault is the San Andreas fault?
A strike-slip fault with a right lateral
