exam 2
What is the minimum number of seismic station needed to locate an earthquake?
3
What is the first seismic wave to reach the surface?
P- wave
What is physical weathering in arid regions?
Slower than in humid regions because some processes are less effective
Landforms in arid regions are more _____________ than in humid regions bc ________
angular; soil creep is less common
Limestones are easily eroded in humid regions. In arid regions , limestones
are most resistant and can be cliff formers bc of the scarcity of water
Why does the ground shake during an earthquake ?
because of seismic waves
Why is wind erosion and deposition more important in arid regions than humid regions?
because theres no soil moisture to hold sand grains together at the ground surface
How does wind erode solid rocks?
by abrasion
Arid landscapes tend to___________
change more slowly than humid landscapes
Most earthquakes are
concentrated at plate boundaries
a talus pile is a _________ feature produced by ________
depositional; physical weathering and gravity
Streams in arid regions may
flow only during rainy season, leak water into water table during dry seasons, and erode by the same processes as do streams in humid regions
In a basin surrounded completely by mountains (like death valley), streams
form playa lakes, evaporate to produce salt flats in the basin, and deposit alluvial fans , partially filling the basin with sediment
Arid regions may be
found at the north and South Pole regions, characterized by large amounts of sand, characterized by mostly rocky landscapes
The intensity of an earthquake is the measure of
how much damage the earthquake caused
The magnitude of an earthquake is a measure of
how much energy was released during the fault that produced the earthquake
What are remnant of highlands nearly covered by a blanket of sediment called?
inselbergs
Good tombstone in arid regions but not in a humid region?
marble
During transmission of a Rayleigh wave, particles in a rock _____________ as the energy passes through the rock
move in a circular path
What is chemical weathering in arid regions?
much less effective because there is little water available
What does the shape of a sand dune and its position relative to the wind depend on?
the amount of sand available, how constant wind direction is, and the strength of the wind
In transverse sand dunes
the gentle side faces the direction from which the wind is blowing
The farther an earthquake epicenter is from a seismic station
the greater the delay time between arrival of P and S waves.
What is the focus of an earth quake?
the point below earths surface where energy was released
What is the epicenter of an earthquake?
the point on earths surface closest to where the rock broke
What does a travel time curve show graphically?
the velocities of the different kinds of seismic waves
During transmission of a P- wave, particles in a rock ____________ as the energy passes through the rock
vibrate parallel to the direction in which the wave is traveling
During transmission of an S-wave, particles in a rock ______________ as the energy passes through the rock
vibrate perpendicular to the direction the wave is traveling
When does liquefaction occur during an earthquake?
when vibration. causes water to coat sediment grains, greatly lessening friction. (quicksand)