Earth Science 9-13
The two components of gravity on a slope are_______ (gs) and ______(gp) to the slope.
Parallel, perpendicular
The primary process that breaks rocks into fragments is __________ weathering. These rock fragments fall or reduce cohesion of the slope and release large boulders or quantities of material downslope.
Physical
When rocks and minerals are broken down into smaller and smaller pieces but retain their original molecular structure, they have undergone
Physical weathering
What attribute of the slopes in the Sierra de Avila on the Caribbean coastline of Venezuela makes this area prone to landslides?
Large vertical decreases over a short horizontal distance
The oldest of the World Heritage Sites are significantly older than the younger World Heritage Sites. What advantages do the oldest of the sites have over younger sites?
The oldest sites are made of durable materials. The oldest sites have outlasted much younger sites that have been reduced to rubble or completely destroyed.
The oldest World Heritage Sites are nearly five times older than the youngest sites. What characteristics have allowed for their preservation?
The oldest structures are constructed of rock and materials resistant to weathering.
he oldest World Heritage Sites are nearly five times older than the youngest sites. What characteristics have allowed for their preservation?
The oldest structures are constructed of rock and materials resistant to weathering.
Which of these are examples of flora and fauna that contribute to macroscopic biological weathering?
Trees Sea urchins
True or false: In events such as the rockfall at Sacred Falls in Hawaii during May 1999, there may be no conclusive reason for a rockfall other than long-term weathering.
True
True or false: Investigative research of weathering sites focuses on how processes in the natural world, in addition to human factors, affect weathering rates.
True
A(n)___________ is a common term for a mass wasting incident that occurs very, very quickly.
landslide
Mountain ranges in the western United States have a ______ risk of slope failure compared to the eastern Appalachian Mountains, despite the fact that the western mountains are taller.
decreased
In the cycle of rock weathering, chemical weathering alters rocks to be more susceptible to physical weathering, which breaks rocks up for further exposure to chemical weathering. Therefore, one can conclude that chemical and physical weathering ______ each other.
enhance
This image shows a geological feature formed from erosion called a(n)
exfoliation dome
Rocks with_________ porosity are more susceptible to weathering.
higher
Soil erosion rates vary around the world due to soil type, climate, topography, and land use. Africa, South America, and Asia currently experience ______ soil erosion rates, while Europe and North America experience ______ soil erosion rates.
hight, low
Soil formation is dependent on a great many factors to be successful. Even after soil is formed, in areas ______, newly formed soils can be quickly washed away by water.
of steep topography
Rockslides are prevalent on hillsides that are ______ to the bedding planes of underlying rocks because these are zones of weakness.
parallel
The two components of gravity on a slope are_________ (gs) and________ (gp) to the slope.
parallel and perpendicular
What common mineral is very resistant to weathering and is rarely affected by dissolution, hydrolysis, or oxidation at low temperatures on Earth's surface?
quartz
Conservation tillage is a _______ that is(are) employed to reduce water and wind erosion
set of agricultural techniques and practices
The overall effect of rockfalls on humans is ______ because these events usually occur in remote areas and involve small amounts of material.
small
To stabilize slopes near roadways, two elements are applied. First, drainage needs to be improved, and second, ______.
surface material needs be physically secured to bedrock
Fill in the blanks to complete the sentence. The pile of fallen rocks at the bottom of a steep slope is called a(n) ____________ slope.
talus
Fragments of rock that have broken free of mountain or cliff sides and tumbled downslope into heaps of broken rock are known as___________ slopes.
talus
Soil formation is greatly affected by ______, which influences chemical weathering rates, and ______, which influences both chemical and physical weathering processes.
temperature; precipitation
Dissolution is the process of minerals contained in a rock being dissolved by
water
Frost wedging is a type of weathering process in which
water infiltrates cracks, then freezes and expands to push rocks apart
occurs when water infiltrates into small cracks, freezes, expands, and pushes the rock apart. (Use a single word for your answer.)
wedging
True or false: In observations of slope failure due to excess water, heavy rainfall is the sole factor.
False
The slopes of the Sierra de Avila in Venezuela often reach angles greater than ______ degrees, which results in catastrophic landslides once or twice a century.
30
Multiple Choice Question What is the maximum angle of slope that a pile of dry sand, such as in the image, will form? Compare this to the vertical slope moist sand can be sculpted into.
35 degrees
What is the maximum angle of slope that a pile of dry sand, such as in the image, will form? Compare this to the vertical slope moist sand can be sculpted into.
35 degrees
In Venezuela, a catastrophic flow occurred on December 15, 1999, after ______ of rain fell over three days. The event resulted in the deaths of 19,000 people. The flow deposited debris up to _______ thick and caused $2 billion in damages.
36 inches; 16 feet
Which of the following describes a talus slope?
A mound of broken rock fragments at the bottom of a cliff or mountainside
What type of mass wasting event occurs when rocks fall from a very steep slope?
A rockfall
Which of the descriptions below defines soil?
A stratified mixture of regolith, organic material, water, and air that can support plant life
What is the name of the landform created from a rockfall?
A talus slope
What are the two goals of engineered slope stabilization?
Anchor the material to the slope Reduce the role of water
Between western US mountain ranges and the Appalachian Mountains, where is there a greater risk of slope failure? Multiple choice question.
Appalachian Mountains
What defines the climate of a region?
Average precipitation Average temperature
The weathering of rocks on or near Earth's surface is dependent on which factors?
Climate Rock composition Rock properties
Along with states on the Pacific Coast and in the Appalachian Mountains, which state has a high incidence of slope failures?
Colorado
Aside from water, what are other causes of mass wasting?
Earthquakes Excavations Structure loads Traffic
Disturbances to slopes that can cause slope failure include water, poorly planned excavations, excessive weight due to structures, and vibrations. What are causes of vibrations that could cause slope destabilization and mass wasting?
Earthquakes Traffic
What probable rates of erosion and soil formation might be expected in a landscape with steep slopes?
High erosion and slow soil formation rates can be expected.
Which countries have the highest soil erosion rates due to poor soil management? Which countries have the lowest soil erosion rates?
High soil erosion matches Africa, Asia, and South America Africa, Asia, and South America Low soil erosion matches Europe and North America Europe and North America
The porosity of rocks is the amount of space available within a rock for water and air to occupy. Porosity affects weathering. Which of the following kinds of rocks are more susceptible to weathering?
High-porosity rocks
Which of the following ions is exchanged for ions in minerals during the chemical weathering process of hydrolysis?
Hydrogen
What effect does physical weathering, which can take a very long time, have on the stability of a slope?
It can loosen material along joints and reduce overall cohesion. It can break up small fragments of rock that cause boulders to fall.
What effect does chemical weathering have on the stability of a slope?
It forms thick layers of unconsolidated regolith. It requires that ample rainfall be present which may add excessive weight to the slope.
What distinguishes landslides from other forms of mass wasting?
Landslide is a general term for a mass wasting event that occurs very, very quickly.
What human influence might destabilize a slope with excess water?
Leaking septic systems Heavy irrigation Timber harvesting
Observe the soil profiles. Identify which soil profile corresponds to arid and which to temperate climates.
Left profile is arid, and right profile is temperate.
Between lye, which is used to make soap, and a lemon, which substance has more hydrogen ions?
Lemon
Mass wasting events are classified by the type of ________on the slope and the way it moves.
Material
Where do exfoliation domes typically appear?
Mountains
Which two properties are used to classify mass wasting?
Movement type Material type
What is specific about a mudflow compared to a more general flow or slump?
Mudflows consist of finer-grained sediments than debris flows. Mudflows have higher velocities than slumps.
Which of the following earth materials remains unaffected by dissolution, hydrolysis, or oxidation?
Quartz
The weathering of rocks on or near Earth's surface is dependent on which factors?
Rock composition Rock properties Climate
Why are rockfalls rarely hazardous to humans?
Rockfalls most often occur in isolated areas and involve fairly small amounts of material.
Which of following best describes the process of chemical weathering?
Rocks and minerals are broken down due to a change in their composition.
Will slope failure cause a rockslide on the slope where rock layers are parallel to the slope (area B), or on the slope where rock layers are at an angle to the slope (area A)?
Rockslides will occur on the slope with rock layers parallel to the slope.
Which of the following sentences is correct regarding the time it takes to form soil?
Small amounts of soil form over thousands of years in cold regions or in just a hundred years in the tropics.
is defined as a mixture of regolith, organic material, water, and air that can support plant life.
Soil
What kinds of landforms or regions have the greatest risk for slope failure in the United States?
The Pacific coastline The Appalachian Mountains
Imagine a slope that receives a large quantity of precipitation over a period of two days. What could be happening to that slope during the rainfall?
The chances of slope failure are increasing as the soil becomes saturated, which increases weight and reduces cohesion.
Recall the equation representing the force of gravity and its components G2G2= gsgs2 + gpgp2. We know that G, gravity, is constant. If gpgp acting on a object sitting on a hill has increased, what has happened to the hill's slope?
The hill's slope has decreased or become less steep.
What are the characteristics of a flow, such as a mudflow or debris flow? Multiple select question.
The material is a turbulent mixture of soil, rock, and water. The flows are fast moving with properties similar to liquids. The flows follow preexisting channels.
The December 15, 1999, Venezuelan flow resulting from slope failure of hillsides followed a precipitation event of 36 inches of rain. The flow caused enormous damage and the deaths of at least 19,000 people. What was the maximum speed the slurrylike mixture reached?
Up to 30 miles per hour
Why does excess water in slope materials increase the chance for slope failure?
Water reduces cohesion between grains. Water held in the pore spaces of the slope will increase the total weight of the slope material.
The physical, chemical, and biological breakdown of rocks and minerals is collectively known as
Weathering
What is the name for the process of breaking down rocks and minerals into smaller pieces or altering the rock material through physical, chemical, or biological means?
Weathering
When scientific research is employed at sites affected by weathering, what kinds of questions are asked to guide the investigative process?
Why do some rocks weather faster than others?, What can be done to stop or slow down natural weathering processes?
Soil profiles with caliche layers and thin topsoils are typically found in ______ climates, whereas soil profiles with thick topsoil and clay layers are typically found in ______ climates.
arid; temperate
In regions of rapid ________weathering, regolith is formed quickly and is susceptible to slope failure. The regolith is bound loosely together and experiences excessive loading and saturation from water.
chemical
The weathering process in which rocks and minerals are broken down and change forms both physically and on a molecular level is called ___________ weathering.
chemical
The cycle of rock weathering is caused by chemical and physical processes working together; it follows that a chemically weathered rock, composed of weaker minerals, is susceptible to physical weathering processes that will increase surface area for further ______.
chemical weathering
Average temperatures and average annual precipitation characterize the____________ of a region.
climate
Failure of slopes made of unconsolidated materials is less likely if the materials are , meaning some medium, such as water, would help hold grains together.
cohesive
The water in slope materials ______ the force that acts perpendicular to the slope, thereby ______ the likelihood of slope failure.
decreases; increases
The chemical weathering process of ______ occurs most frequently in sedimentary rocks as minerals form a solution with available water.
dissolution
The component of gravity pulling material downslope is opposed by a force called
friction
Mass wasting is the movement of earth materials downslope by the influence of ______.
gravity
As the steepness of a slope increases, the likelihood of objects falling down the slope increases as well. Knowing that gravity is constant, which component of gravity has increased when the steepness of a slope increases?
gs
The stone in the image is stationary, not moving downslope, due to the force of friction. Which of the labeled parts of gravity (a component or the entire force of gravity) does the force of friction oppose?
gs
The pH scale is a measure of how many__________ ions are present in a solution. Listen to the complete question
hydrogen
The pH scale is a measure of how many___________ ions are present in a solution.
hydrogen
is a chemical weathering process in which hydrogen ions in water replace ions in silicate minerals, resulting in a weaker mineral that is susceptible to physical weathering.
hydrolysis
The soil in the image has the characteristic red color of soils that contain iron and aluminum oxides. All soluble ions have been leached from the soil profile, giving it a smooth, uniform coloration with few horizons. This type of soil is called a
laterite
The fracturing of rocks by plant roots or burrowing of animals are two examples of ______ biological weathering.
macroscopic
The phenomena called___________ wasting is the movement of material downslope under the influence of gravity.
mass
Microscopic production of soil is primarily generated by _____________decay.
microbial
Microbial decay is the leading contributor of ______ soil production.
microscopic
is a chemical weathering process where oxygen reacts with metals in rock, such as iron, to create new mineral compounds with a hallmark red color.
oxidation
The coloration of the rocks in the image comes from the reaction of iron or other metals and ______, which is known as oxidation.
oxygen
Unconsolidated materials such as sand are less susceptible to slope failure when there is sufficient cohesion. Cohesion is ______.
present when a small amount of water holds grains together by surface tension
is a soil component made of rock and mineral fragments that are the products of bedrock weathering.
regolith
Rock weathering rates are dependent on climate, which dictates which processes can occur and which cannot; rock properties such as cracks or fissures; and ______, which determines the vulnerability to chemical weathering processes.
rock composition
A(n) is a type of mass wasting event in which rocks are dislodged from steep slopes or cliffs.
rockfall
Water passing through small cracks in rocks can precipitate________________ crystals, which over time will grow and cause wedging in rocks.
salt
The weathering process of wedging can occur due to freezing water or ______ entering cracks in rocks and expanding.
salts
A laterite is a soil where all ______ have been flushed or leached due to plentiful rainfall, which leaves behind iron and aluminum oxides.
soluble minerals
A laterite is a soil where all ______ have been flushed or leached due to plentiful rainfall, which leaves behind iron and aluminum oxides. Multiple choice question.
soluble minerals
Wire mesh coverings, pouring cement on slopes, and anchoring bedrock with large bolts are all methods of slope that reduce the possibility of slope failure along roadways.
stabilization
Physical weathering can be described as
the disintegration of rocks and minerals into smaller pieces
What is regolith?
the layer of unconsolidated rocky material covering bedrock.
Temperature and the amount of precipitation affect soil formation by influencing ______.
the quality of the soil soil thickness weathering rates
Techniques used in agriculture to protect soil from erosion are collectively known as conservation
tillage
The ______ required for the necessary physical and chemical weathering processes to create soil varies with the climate.
time
Water and ______ are soil's greatest adversaries because they will wash or blow soils away when soils become dry or lack organic matter and vegetation cover.
wind
Water and __________ are soil's greatest adversaries because they will wash or blow soils away when soils become dry or lack organic matter and vegetation cover.
wind
