Test 2

GEOL113

Hydrologic cycle

Evaporation, precipitation, surface runoff and excesses over land and over the oceans

How do rivers flow?

Downhill

How do you determine which way a river is flowing on a map?

You use contour lines. Water flows through the mouth of the V.

Headwaters

Source area of a stream where it typically enters the sea, lake, or larger stream.

Mouth

End of a stream where it typically enters the sea, lake, or larger stream.

Gradient

Slope of a stream bed along its course.

Floodplain

A broad, flat area adjacent to a river;flat area of sediment deposited by the stream, risk of flooding depending on the river level

Stream channel

A long, narrow depression, shaped and filled by a stream

Stream bank

Sides of the channel

Streambed

bottom of the channel

Point bar

where the stream flows slowest around a bend and deposits sediment

Cutbank

Where the stream flows fastes around a bend and erodes away sediment

Meander scar

Remnants of a meander: an oxbow lake filled with sediment

Oxbow lake

Cut off meander when stream pinches off due to erosion

Sinuous

How bendy a stream is; straighter streams are less sinuous.

Zone of saturation

The area of underground soil/rock that is completely saturated with groundwater

Water table

Top of the saturated zone that separates groundwater from soil moisture above.

Glaciars

Body of ice and snow flowed on land that shows downslope or outward movement under the influence of gravity

Moraines

Accumulation of glacial debris pushed along by ice flows

Lateral moraines

At the side of a glacial

Median moraines

In the middle of a glacier formed when two lateral moraines meet

Terminal moraine

At the furthest extent of the glacier where debris is deposited.

Outwash plain

A gently sloping plane made by sand and gravel deposited from streams flowing from the front of the glacier.

Drumlin

Elongated/streamlined hill parallel to direction of ice movement

Kettle

A depression created when ice blocks are lodged in glacial deposits, then melt and can fill with water to form kettle lakes.

Esker

Long, sinuous ridge of melt water-deposited sediment

Glacial drift

All rock material transported by a glacier and deposited directly from the ice or by meltwater from the glacier.

Kame

Steep-sided hill made when outwash collects in stagnant glacial ice

Arete

A sharp, narrow ridge formed between two glacial valleys as glaciers erode the sides of a mountain.

Horn

A sharp, pyramid-shaped peak formed when multiple glaciers erode a mountain from different sides. It appears like a triangle on topographic maps

Cirque

A bowl-shaped depression with steep sides and a flat or gently sloping floor

Tarn

A small mountain lake that forms in a cirque after glacial retreat, often from melted glacial ice.

U-shaped valley

A valley with a broad, flat floor and steep, nearly vertical sides, carved by the movement of a glacier.

Hanging valley

A smaller valley that was carved by a tributary glacier; sitting upstream of a cliff

Earths stucture

Crust/lithosphere, mantle, outer core, inner core

Plate tectonics

Pieces of the crust that move gradually across the earth’s surface

Divergent boundary

Two plate are moving away from each other while new crust is being formed. Volcanes are common and it can cause shallow, weak earthquakes.

Convergent boundaries

Two plates that move towards each other and destroy crust. The denser plate sinks into the mantle while the other overrides creating a subduction zone.

Transformative boundary

Two plates that slide past each other. Crust is neither created or destroyed and it can cause shallow, medium strength earthquakes.

How do you calculate the rate of seafloor spreading at a mid-ocean ridge?

Identify two matching magnetic anomalies (same age) on opposite sides of a mid-ocean ridge, Measure the distance between them using the map scale, and Find the age of the anomalies (in years).

Use the formula: Rate = Distance ÷ Time (e.g., cm/year or mm/year)

Earth’s magnetic field

Generated by the rotation of Earth’ liquid outer core. Geographic North and Magnetic North are not the same and can point in different directions.

Normal polarity

magnetic field points the same way as geographical North and South.

Reversed polarity

North and south magnetics poles switch

Hotspots

Source of heated magma that lies deep within Earth’s interior.

Sesimology

The study of Earth’s elastic vibrations, the sources that generate them, and the structures through which they propagate

What causes on earthquake?

Movement between tectonic plates in the lithosphere causes sudden ground shaking

What is the difference between an epicenter and a hypocenter?

Hypocenter is the underground origin of the quake: epicenter is the surface point directly above it.

What are the main types of seismic waves?

Body waves (P and S waves) and surface waves

Describe P-waves

Primary, compressional, fastest, vibrate parallel to motion, first to arrive.

Describe S-waves

Secondary, slower, vibrate perpendicular to motion, higher amplitude than P-waves.

Why can’t S-waves travel through the outer core?

Because the outer cores is liquid and S-waves can only move through solids.

Seismometer

Measures ground motion

Sesimograph

Records ground motion

Seismograms

A record produces by a seismograph

How do you calculate the distance to an earthquake epicenter?

Find arrival times of P and S waves, subtract Ts-Tp- time difference, use a travel-time graph to convert time into distance

How do you triangulate an earthquakes location?

You use the distance from three seismometers to draw circles; the point where all three intersect is the epicenter

What does the Richter scale measure?

Magnitude - the amount of seismic energy released

What does the Modified Mercalli Intensity scale measure?

Intensity - how much shaking people feel and observe at the surface