GEOL 113 Exam 2

96\.50%

Relative distribution of water: oceans

1\.76%

Relative distribution of water: Glacial Ice

1\.70%

Relative distribution of water: Groundwater

0\.014%

Relative distribution of water: Lakes and Rivers

0\.001%

Relative distribution of water: Soil moisture

0\.001%

Relative distribution of water: Atmosphere

Evaporation

Water changing from liquid to gas (water vapor) driven by heat from

Surface Runoff

Water flowing on land surface downhill to oceans

precipitation

Any liquid or frozen water that forms in the atmosphere and falls back to the earth.

longitudinal profile

plot of evaluation of river from head (source) to mouth (end)

longitudinal profile near the headwaters

\-Gradient is steep and velocity is high

\-channel roughness is high

\-discharge is low

\-channel size is low

\-erosion

Longitudinal profile near the mouth

\-gradient flattens (is lower)

\-channel is smoother but meanders

\-discharge is high

\-channel size is wide

\-transportation

Gradient

Change in elevation as function of distance from head to mouth

Near the headwaters

Where is gradient the highest?

Near the mouth

Where is gradient the lowest?

Excess in evaporation vs precipitation

The amount of water evaporated is the same as the excess amount of precipitation

What balances the excesses?

The excess precipitation “runs off” into the oceans making everything level

Watershed (drainage basin)

The area of land over which precipitation falls, it would be drained by rivers in that basin

Continental divide

splits a continent into different drainage basins

Discharge

volume of water passing a point per unit of time

Discharge increases

How does the discharge of a stream change downstream?

They compete in terms of velocity from head to mouth. Gradient decreases while discharge increases

How velocity is dependent on both discharge and gradient

high

At the start, near the head velocity is _____ because of steep gradient

Slows

In the middle it hits a switch off where the velocity _____.

high

At the end, near the mouth the velocity is _____ due to high discharge

competence

The maximum size of sediment transported

Capacity

The maximum load of sediment transported

floodplain

an area of low-laying ground adjacent to a river, formed mainly of river sediments and subject to flooding. Formed over time by the meandering stream

Meander

bends or curve in river/stream, water velocities are lower on the inside and higher on the outside.

point bar

On the inside of a meander, the low velocity and low competence cause deposition.

Ox bow lake

On the outside of a meander, so much erosion causes the meander to break off because of high velocity and competence.

Delta

Consists of sediment deposited at the mouth of a stream. When a stream enters standing war, the current slows, loses competence, and sediments drop out.

Alluvial fan

Conical, fan shaped structures that build at the base of a mountain font. Sediments drop out rapidly with a change in stream gradient.

flood

When a river/stream overflows its bank

Natural levees

Deposits that occur along banks of rivers/streams during floods. Raised areas adjacent to the channel formed during a flood event

X-year flood

possibility that only once in X years that amount of flood size will occur again

2-3 year flood cycle

During what flood cycle does the river do most work of erosion and transport

porosity

\-groundwater resides in subsurface pore spaces

\-the measurement of voids

permeability

\-The ease of water flow due to pore interconnectedness

\-high=flow easily

aquifer

sediment or rock that transmits water easily

aquiclude

material that water cannot easily flow through (low permeability)

Water table

A subsurface boundary between zone of aeration and saturation

Zone of aeration

where voids are filled with water or air or partially filled

Zone of saturation

Where voids are filled with water

.00002km per hour

How fast does groundwater move?

Confined aquifer

An aquifer beneath an aquitard, isolated from the surface and less susceptible to pollution

unconfined aquifer

An aquifer that intersects the surface, is in contact with the atmosphere and easily contaminated

Well

Holes excavated or drilled to obtain groundwater

Cone of depression

a dip that happens in water line when too much groundwater is withdrawn

Caves

\-Develop when groundwater dissolves limestone

\-grow as joints and widened by dissolution of the limestone

groundwater contamination

\-Human activities (metals, microbes, organic/inorganic compounds

\-sewage

\-animal feedlot runoff

\-highway salt

\-fertilizers and pesticides

\-chemical and industrial materials

\-underground storage tanks

Salt water encroachment

The movement of saltwater into underground sources (aquifers) of freshwater.

salt water encroachment process

If too much freshwater is pumped from the aquifer system, then saltwater can migrate landward

portable water

Drinking water, comes from surface and ground sources and is treated to levels that meet state and federal standards for consumption

PPM

Parts per million, the measurement of mass of a chemical or contaminate per unit volume of water.

PPB

Parts per billion, The measurement of mass of a chemical or contaminate per unit volume of water

The 6 major types of groundwater contaminants

1. Microbial
2. lead
3. nitrates
4. arsenic
5. disinfection byproducts
6. pesticides
7. solvents

glacier

A thick mass of ice that forms over hundreds to thousands of years by the accumulation, compaction, and recrystallization of snow

10%

What percent of the earth is covered by glaciers?

alpine glaciers

glaciers that flow from high to low elevation in mountain settings

Continental ice sheets

Vast ice sheets covering large land areas, ice flows outward from thickest part of sheet

less

Ice is ____ dense than water

more

The heat capacity of water is _____ than the heat capacity of ice

Striations

When rocks contained within the glacier come into contact with other rocks

cirques

a bowl shaped basin high on a mountain

horn

a pointed mountain peak formed by three or more cirquesu-

arete

a knife-edge ridge formed by two cirques that have eroded towards one another

u-shaped valleys

glacial erosion created a distinctive trough, unlike v-shaped fluvial valleys

hanging valleys

the intersection of a tributary glacier with a trunk glacier, waterfall results

fjords

u-shaped glacial valleys flooded by the sea

drift

Material transported and deposited by a glacier or by glacial meltwater

tilt

Sediment dropped by glacial ice, consists of all grain sizes

outwash

Deposit of sand and gravel carried by running water from the melting ice of a glacier.

lateral moraine

debris formed along the flank of a valley glacier

medial moraine

mid-ice moraine from merging lateral moraines

end moraine

debris formed at the toe of the glacier

ground moraines

Debris formed at the bottom of a glacier

drumlins

Hills of sediment that have been streamlined by glacier flow

esker

ridges made of sand and gravels, deposited by glacial meltwater flowing through tunnels within and underneath glaciers.

Varves

an annual sediment layer

earthquake

Earth shaking caused by sudden release of energy, usually due to tectonic stresses along faults

Focus (hypocenter)

The spot within the earth where eqarthquake waves originate

epicenter

point on earth’s surface directly above the focus

seismograph

Instruments used to record the motion of the ground during an earthquake

body waves

Waves that can pass through the body of the earth faster than surface waves, have short periods most energetic near earthquake hypocenter

surface waves

Waves that move near the surface only, slower than body waves-linger

p-wave

\-fastest waves

\-are compressional like soundwaves

s-waves

\-arrive second to seismogram

\-are shear waves: particle motion is perpendicular to wave propagation

no

Can an s-wave travel through liquid?

intensity

scales used to observe property damage to estimate the amount of ground shaking

magnitude

scales use data from the seismographs to estimate the amount of energy released

Richter scale

Is based on largest amplitude and accounts for distance from the hypocenter

Modified mercalli cale

The degree of shaking damage

Amplitude

Each unit on scale means 10-fold difference in wave ______

Energy releases

Each unit on scale means 32-fold difference in ______

lithospheric plates

Most earthquakes occur at the boundaries between _________

Crust

The outermost rocky “skin” of earth with variable thickness

Mantle

The region of earth’s interior between the crust and the core, believed to consist of hot, dense, silicate rocks

Outer core

liquid layer of the core, molten due to high heat

inner core

hotter than the outer core, subjected to extremely high pressure causing it to remain solid.