Earth Science- Earthquake and Volcano Flashcards
Where do earthquakes occur?
On fault lines; near plate boundaries
Crack in the crust where rocks have moved, NOT along a plate boundary
A fault
Name the four types of faults
Normal
Strike
Reverse
Dip- Slip
Which direction do normal Faults move in?
◀️▶️
Which direction do Strike Faults move in?
◀️
▶️
Which direction do Reverse Faults move in?
▶️◀️
Which direction do Dip-Slip Faults move in?
↔️↕️↘️↗️
What are the 3 types of seismic waves?
Primary, Secondary, and Surface
What is the slowest wave?
Secondary
What is the first wave to arrive at a seismic station?
Primary
What is the most destructive type of wave?
Surface
What type of waves move side to side?
Primary
What types of waves move at right angles?
Secondary
What types of waves have vertical and horizontal displacement?
Surface
What type of wave is the fastest?
Primary
Where is the focus?
Beneath the surface
Where is the epicenter?
On the surface
The spring back of a rock. Is reacts like a rubber band
Elastic rebound
Smaller earthquakes that follow the main earthquake
Aftershock
Instrument to measure earthquakes
A seismograph
What tells you the info on the seismograph
Seismogram
A small earthquake that often precede a major earthquake by days, or in some cases, by as much a several years
Foreshock
What wave arrival times do geologists measure between?
Primary and secondary
Relationship between arrival time and distance to the earthquake epicenter:
The greater the interval between the arrival of the first Primary wave the the first Secondary wave, the greater the distance to the earthquake.
How many seismic stations are needed to locate an earthquake?
Three
The process of locating an earthquake
Triangulation
Scale that is most commonly used to measure earthquakes
Richter scale
What does the Richter scale go from?
1-10
At what magnitude can we feel an average earthquake?
3.0
A weak spot in the crust where molten material, or magma comes to the surface
Volcano
The resistance of a liquid flowing
Viscosity
What happens when lava is highly viscous?
It forms a plug in the pipe which rises or is blown out and becomes sticky
Example of high viscosity
Syrup, honey
Example of low viscosity:
Water, vinegar
What does the viscosity of magma in a volcano depend on?
Silica content and temperature
Relationship between silica and viscosity:
The more silica magma has, the higher is viscosity
The less silica magma has, the lower its viscosity
Types of volcanoes:
Sheild, Cinder come, and composite
A broad, slightly domed structure. It looks like a pancake
Shield volcano
What do shield volcanoes erupt?
Basaltic Lava
Steepest smile at which material is still stable: small
Cinder cone Volcano
What do cinder cone volcanoes erupt?
Cinder (tephra)
A large, nearly symmetrical structure
Composite volcano
What does a composite volcano erupt?
Alternating layers of lava and pyroclastic materials mater
An explosive eruption that girls out a mixture of hot gases, ash, cinders, and bombs
Pyroclastic flow
A type of mudflow; ash and water mixed to create mud that runs down the side is a volcano
Lahar
Name the three types of magma
Basaltic Magna, Andesitic Magma, and Rhyolitic
What is the silica content of basaltic magma?
Least 50%
What is the silica content of Andesitic magma?
Intermediate 60%
What is the silica content of Rhyolitic?
Most 70%
One of the most abundant materials in the earths crust. Made of oxygen and silicon
Silica
The vibration of Earth, produced by the rapid release of energy
Earthquake
When do earthquakes occur?
When there is a break in rock mass along which movement has occurred (when places move)
What does high viscosity indicate?
It is sticky
What does low viscosity indicate?
It is runny
What happens when there is more silica magma and the viscosity is high?
It is going to be light in color
What happens when there is less silica magma and the viscosity is low?
It will be high in color
How do composite volcanos explode?
Quietly and destructively
