Midterm 2- Dynamic Earth Flashcards
Cross section of a stream and velocity
The deepest part of the stream has the highest velocity.
Outer vs inner portion of a meandering stream
Outer parts of meander:
→ velocity is highest
→ erosion
→ cutbank
Inner meander bends :
→ velocity is low
→ deposition
→ point bars
Liquefaction
Loosely packed, water-logged sediments at or near the ground surface lose their strength in response to strong ground shaking. Causes major subsidence, fracturing, and horizontal sliding of the ground surface
Describe the process that causes a nonconformity
Occurs where rocks that formed deep in
Earth are overlain by sedimentary rocks
formed at the Earth’s surface. Indicates that all the rocks overlying the metamorphic or
igneous rocks have been removed by
uplift and erosion.
Hanging valley
formed when the main glaciers cut deeper than side tributaries
Kame
Hills formed by sediment deposition
in/on ice – left after the glacier melts
earthquakes that follow the largest shock of an earthquake sequence
Aftershock
Glacial erosion and deposition
Glaciers move, pick up & transport
rocks and Glaciers transport material and melt
Amplification of seismic waves
Soft sediments amplify seismic vibrations increasing damages
sheets of floating ice attached to land usually occupy coastal embayments
Ice shelves
Surface faulting
Displacement that reaches the Earth’s
surface during slip along a fault.
* Commonly occurs with shallow
earthquakes (epicenter <20 km.)
* May accompany aseismic creep or
natural or man‐induced subsidence
Shallow Earthquakes
Form through tension and normal faulting at divergent boundaries; strike-slip at transform faults
The four wave types
A)Body waves
1)P waves
2)S waves
B)Surface waves
3)Love wave
4)Reighleigh wave
the degree of earthquake shaking at a given locale based on the amount of damage
Intensity
Types of stream deposition features
1)Flood plains
2)Terrances
3)Alluvial fans
4)Deltas
Horizontal fold
is a special type of fold in which both limbs are parallel but offset to each other. The limbs are horizontal, or nearly so.
Ground failure
The term ground failure is a general reference to landslides, liquefaction, lateral spreads, and any other consequence of shaking that affects the stability of the ground.
Graded profile
a smooth concave profile which is steep as the source(high erosion) and gentle at the mouth (high deposition)
Terrances
when streams carve downward into their floodplains, leaving discontinuous remnants of older floodplain surfaces as step-like benches along the sides of the valley
Anatomy of a delta
1)Topset beds- at the very surface of the delta and sit on the foreset beds
2)Foreset beds- sit under the topset bed and form a slope towards the bottomset bed
3)Bottomset beds-lowest bed at the bottom of the body of water, made from the progradation of the foreset bed
Continental glacier
Glaciers much larger than Alpine glaciers that cover entire land masses
Moraine formed as the ridge of till at front of a stable glacier
End moraine
Flashflood
A flood caused by heavy or excessive rainfall in a short period of time
a mountain glacier whose flow is confined by valley walls, forms a U shape
Valley glacier