Geology Lab Quiz 2 Georgia Southern Professor Schenk

A ratio scale of 1:1000 on a topo map indicates that _______.

1 unit on the map equals 1000 units in the real world

On a map with a scale of 1:24000, what would the ground distance be if the map distance is 5 inches?

1.89 miles

During the past 99 years, what year you saw the greatest flood on the Flint River at Montezuma?

1994

A 50-year flood is one that has a _______ chance of occurring every year.

2%

What is the percent grade of a hill with a gradient of 145 ft/mile?

2.7%

What was the elevation of the Flint River during that greatest flood?

290ft

River discharge is a product of river channel width, depth, and streamflow velocity. If you know a specific river channel cross-section is 27 ft wide and 2.74 m deep, and streamflow velocity is 22 ft/s, what is the river discharge in ft3/s? (Note: 1 m = 3.28 ft)

5338 Ft/Sec

Bankfull stage for the Flint River is 270 feet. Therefore, flood stage is any river elevation greater than 270 feet. What is the approximate probability that the Flint River will flood every year?

77%

If the Flint River has a velocity of 0.36 ft/s, and the channel width is approximately 18 ft during bankfull stage, what is the discharge of the river at bankfull stage?.....(Hints: River channel depth is essentially the difference between the elevation of the river gage station 255 ft and the elevation of its bankfull stage 270 ft.)

97.2 cu. ft/sec

_______ lava is low viscosity, has a temperature of 1200°C, and typically forms _______ volcanoes.

Basaltic / Sheild

If you are traveling from one point to another on a topographic map and there are no elevation values on the contour lines, how can you tell if you are moving uphill?

Contour circles get smaller as you move uphill.

River downcutting will continue as long as there is water in the channel.

False

Water flows faster in the inner side of a meander river bend and erode the inner side of the river bank.

False

A _______ occurs whenever the volume of water flowing in a channel is greater than the channel's storage capacity.

Flood

What poses the greatest hazard living next to a shield volcano?

Lava flows that people can outrun, but vegetation and buildings can't

A raised embankment along a river channel, either natural or man-made, that holds back flood waters is called a _______.

Levee

Which of the following areas of the United States are highly susceptible to earthquakes?

Pacific Coast / Central Mississippi River Valley

In addition to temperature, magma viscosity is also controlled by________

Silica Content / Si02

A river that has been channelized actually has a greater risk of flooding than if the river's natural course had been left unchanged.

True

During an earthquake, buildings oscillate. If the frequency of this oscillation is close to the natural frequency of the building, resonance may cause much greater damages.

True

_______ in the upper troposphere can gum up jet engines in flight and may even cause temporary global cooling by reflecting incoming solar radiation.

Volcanic Ash

A set of tick marked circles inside circles on a topographic map indicate a

a depression

How are streams indicated on a topographic map?

by contour lines that form V's which point upstream

Mount Rainier in Washington State is a ______

composite cone

The regular standard change in elevation between any two adjacent contours is known as the _______.

contour interval

The accuracy of a flood-frequency model (best-fit line on a flood-frequency graph) depends on how many _______ are used to construct the model. The more _______, the more accurate the model. (Note: the same answer fills in both blanks)

data points

Topographic high points that separate distinct drainage networks are called____________.

drainage divides

The headwaters of a river is known as the zone of _____, because the steepest gradients and fastest velocities are found there.

erosion

The difference in elevation between two points on a topographic map, divided by the horizontal distance between those two points, and expressed as ft/mile or m/km is called________

gradient

During an earthquake, the amount of ground shaking can vary depending on the material through which the seismic waves are traveling. For example, solid bedrock will experience minimal shaking, while loose sand. mud, and fill will experience great shaking. This phenomenon is called _______

ground amplification

A blue line with dashes and dots along it represents a(n)

intermitten stream

_______ are volcanic mudflows that are typically triggered by heavy rainfall in tropical regions or by the melting of glaciers during effusive lava eruptions on stratovolcanoes

lahars

A raised embankment along a river channel, either natural or man-made, that holds back water is called a ________________.

levee

A very dangerous phenomenon that occurs when seismic waves travel through water-saturated sediment in which the sediment as a whole acts as a fluid, is called _____

liquefaction

Wetlands adjacent to streams, usually on the stream's floodplain, are called _______ wetlands.

riparian

A set of tick marked circles inside circles on a topographic map indicate a

same as any other point along that line

A river's _______ is defined as the height of the water level in the river above some defined zero point, usually sea-level or the river's stream bed.

stage

On a topographic map, the closer the contour lines the _______.

steeper the slope

What type of contour pattern would you expect to see on areas identified as floodplains?

widely spaced