GEOG 140 Midterm

Aswan High Dam How did the Aswan High Dam negatively impact agriculture in the Nile Delta?

(1) Fertile material trapped behind the dam, delta area is becoming increasingly infertile (2) Increase use of fertilizers damages the environment (3) Soil salinization due to no frequent flooding leaching out salts from soil

Three Gorges Dam The positive benefits of the Three Gorges Dam

(1) Hydroelectric power leads to less atmospheric pollution, a reduction of greenhouse gas emission. (2) No nuclear power plants therefore no radiation. (3) Extra electricity will stimulate new manufacturing enterprises which will bring new jobs.

Three Gorges Dam What was lost because of the creation of the Three Gorges Dam

(1) Over 1000 cities, villages and towns were destroyed. (2) Ancient cultural relics will be submerged (3) 1,300 archeological sites will be destroyed (4) Natural beauty of the area will be marred and altered (5) Valuable farmlands were drowned. (6) Extensive coastal erosion since river sediments will be reduced.

Why do people live in close proximity to a volcano?

(1) Soil near by volcanoes contains more nutrients, thus good for agriculture. (2) Geothermal energy. (3) Scenic area, tourism. (4)They have always lived there.

Define the epicenter and the focus

(1) The point above the focus on the earth's surface is called the epicenter (2) The point where the movement occurs is called the focus

Why are some volcanic eruptions very explosive?

(1) The temperature of the magma (2) Its composition (3) The amount of dissolved gas in the magma.

Lake Nyos disaster What were the two theories that provided a possible explanation why the lake ejected carbon dioxide?

(1) Volcanic eruption released CO2 (2) CO2 gradually leaked into and was stored in the lake. It released when lake exploded.

Define lava and magma

(1) When this molten rock emerges out of the vent onto the surface, it is called Lava (2) When molten rock is below the earth's surface it is called Magma

Lake Nyos disaster How tall was the lethal cloud?

328 feet (100 meters)

Lake Nyos disaster What was the average time that some persons remained unconscious?

36 hours

Lake Nyos disaster How many persons in Nyos and Kam survive the lethal gas?

4

Define an earthquake

An earthquake is a trembling or shaking movement of the Earth's surface

Lake Nyos disaster What safety measures were put in place to warn the villagers that danger was immanent in the event of another eruption?

CO2 monitors that are hooked to sirens that would sound if too much CO2 entered the air.

Lake Nyos disaster What was the primary gas in the lethal cloud?

CO2, carbon dioxide.

Lake Nyos disaster Why did the cloud stay close to the ground?

Carbon dioxide (CO2) is denser than air.

Three Gorges Dam Reasons why the river downstream of the Three Gorges Dam will be more polluted

Dam holding back a large percentage of river's volume causing a reduction of the flushing power of the river.

Lake Nyos disaster What signs were there that showed that the volcano was going to erupt?

Farmers heard rumbling.

Know the name of the huge cracks that separate one crustal plate from another

Faults

The reasons why the Three Gorges and Aswan High Dams were built

Generate hydro electricity; Flood control (Navigation; Irrigation; Fishery)

Lake Nyos disaster What was the conclusive reason why the lake erupted carbon dioxide?

Gradual leakage of CO2 from a CO2-rich layer into the bottom of the lake.

What does the Japanese word tsunami mean?

Harbor wave

Define a pyroclastic flow

Hot gases infused with incandescent ash and larger rock fragments.

What to do when a tsunami is approaching

If in deep water, go deeper (further from land); If on the land, go further in land (further from the shore).

Aswan High Dam Extra benefits enjoyed because of the Aswan High Dam

Irrigation; Fishery

Define a volcano

It is a vent or opening at the surface of the earth through which molten material and other materials are ejected.

Lake Nyos disaster What lake erupted on August 15, 1984 killing 37 people?

Lake Monoun

What produces the release of energy when an earthquake occurs

Movement of magma into the crust in volcanoes create seismic waves

Know the most likely places where earthquakes will occur

Plate margins (or boundaries) (Faults?)

Name for the shockwaves that are produced by an earthquake

Seismic (underground) waves

Three Gorges Dam Reasons why persons had to be relocated because of the Three Gorges Dam

The dam flooded 395 miles² of land. Over 1000 cities, villages and towns were destroyed.

Lake Nyos disaster What is the source of the carbon dioxide that is being stored in Lake Kivu?

The magma below. (Bacteria chugging the methane exposing the magma.)

Aswan High Dam Why did the coastal community at the Nile Delta suffer because of the Aswan High Dam?

The missing of nutrients laden waters causes a decrease in phytoplankton thus causes a decrease in fish population then leads to a decline in marine fishing industry.

Aswan High Dam The reasons why the Nile Delta is sinking or will be prone to flooding in the future

There will no longer be tons of sediment deposited by the Nile to counter the natural erosion of the sea, thus causing an increase in coastal erosion.

Three Gorges Dam Why flooding of industrial sites will help to cause potential pollution of the region because of the Three Gorges Dam

Toxic industrial sites were drowned but not adequately cleaned up before the flooding took place.

The reason why tsunamis are dangerous in shallow water

Waves become very high and destructive as they approach shallow water.

Aswan High Dam All other problems associated with the presence of the Aswan High Dam

soil salinity, environmental pollution of the waterways etc