Science Flashcards
Focus
The area along a fault at which slippage first occurs, initiating an earthquake.
Epicenter-
The point on Earth’s surface directly above the focus of an earthquake.
Stress-
The force per unit area acting on a material. When this force exceeds the strength of the rock, strain occurs.
Strain-
The deformation of materials in response to stress.
Fault-
The resulting fracture that occurs in the Earth’s crust when a stress is applied that exceeds the strength of the rock.
Reverse fault-
Fractures that occur as a result of horizontal compression stress.
→ ← Convergence
Strike-slip fault-
Fractures that occur as a result of horizontal shear stress. ↓↑ Transform fault
Types of Stress:
Compression, Tension, Shearing
Types of waves.
P,S,L
Primary, secondary, surface
Richter Magnitude Scale-
Measures earthquake size by amplitude of seismic waves relative to distance.
Moment Magnitude Scale-
Measures earthquake size by the area of rupture surface, amount of displacement along fault and shear strength of faulted rock.
Modified Mercalli Scale-
Estimates earthquake size by structural damage.
Factors effecting earthquake damage
- Magnitude of earthquake
- Distance from epicenter
- Depth to focus
- Nature of ground surface
- Subduction
Volcanoes produced by the melting of crustal plates.
Divergent-
Volcanoes produced by the extrusion of magma at rift zones.
Hot Spots-
Volcanoes produced by the extrusion of magma from unusually hot, stationary regions of Earth’s mantle.
A large mountain with broad, gently sloping sides produced by non-explosive eruptions of mafic magma.
Shield volcano
A cone-shaped mountain formed from hardened chunks of lava produced by explosive eruptions of felsic magma and lava flows.
Composite volcano
2 examples of shield and composite
Sheild: Mauna Loa Hawaii
Composite: Mount St. Helens
