Unit Four - Earthquakes Flashcards
What is an earthquake (6)?
- The shaking and trembling of the earth
- Caused by transform & convergent
- Rocks come in contact.
- Boundaries are jagged
- Creates stress between the plates
- As stress builds up, it releases
- Rocks slip into new positions
What is the focus? (4)
- A point
- Beneath Earth’s surface
- Rocks come in contact & break
- Causing an earthquake.
What is the epicenter?
The point (on earth’s surface) that is directly above the focus.
What are seismic waves?
- Vibrations that travel through the Earth.
- Carry the energy released during an earthquake.
What are primary waves?
- The first seismic waves to arrive
- Compresses like an accordian
- Travels through solids and liquids
What are secondary waves?
- The second seismic wave to arrive
- Travels through ONLY solids
- Can’t pass through outer core
What are love waves?
- Surface waves
- Cause a lot of damage
- Like a ripple in the ground
What detects earthquakes?
Seismograph and Seismogram
What is a seismograph?
Instrument that records the vibrations of seismic waves.
What is a seismogram?
Record that the seismograph makes.
What is the Mericalli Scale?
- Rates earthquakes by intensity and damage
- Ranges from 1 - 12
(Not reliable because there are many varying constants and circumstances that can change and affect the result)
Measures Earthquakes
What is the Ritcher Scale?
- Rates earthquakes by seismograph
- Ranges for 1 - 10
- Most commonly used
Scale of EQ energy:
Each level is 10x stronger than previous level.
What is the Moment Magnitude Scale?
- Estimates total energy released during an earthquake
- Ranges from 1 - 10
Define Travel Time
The time it takes for a seismic wave to travel from the epicenter to a given location.
Define Arrival Time
The time the seismic wave arrives at a given location.
