Geology and Natural Disasters Quiz

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Questions and Answers

What is the primary focus of the law enacted by Professor Haydar Bakr in the UAE?

To establish guidelines for urbanization in drought areas

To regulate water consumption during droughts

To mandate geophysical studies before construction begins (correct)

To reduce desertification risks through construction processes

Which of the following statements accurately differentiates drought from desertification?

Drought can end with the return of water supply, while desertification results in permanent land loss. (correct)

Drought is a permanent condition while desertification is temporary.

Drought results from urbanization, whereas desertification occurs naturally.

Desertification can recover with water supply, but drought is irreversible.

What factor does NOT influence the volcanic risk area according to the characteristics mentioned?

Volcanic ash quantity

Lava viscosity

Silica content

Distance from the nearest city (correct)

What human activities contribute primarily to desertification according to the provided content?

Deforestation and urbanization Signup and view all the answers

In what context are volcanoes primarily mentioned in the material?

In terms of risk estimation around active sites Signup and view all the answers

What happens at the focus of an earthquake?

It is the first point where the fault breaks. Signup and view all the answers

Which wave type arrives first during an earthquake?

Primary wave Signup and view all the answers

What is the primary cause of earthquakes according to the Elastic Rebound Theory?

Release of built-up tension along faults. Signup and view all the answers

Which statement about surface waves is correct?

They are typically the slowest waves. Signup and view all the answers

Which of the following cities is NOT known for being near a tectonic plate boundary?

Berlin Signup and view all the answers

What is the term for the point on the Earth's surface directly above where an earthquake originates?

Epicenter Signup and view all the answers

What are the potential hazards associated with earthquakes?

Aftershocks and landslides Signup and view all the answers

During which geological phenomenon does liquefaction typically occur?

During an earthquake. Signup and view all the answers

What phenomenon occurs when water escapes from an aquifer to the earth's surface during an earthquake?

Liquefaction Signup and view all the answers

Which factor is NOT a contributor to landslides?

Tectonic plate movement Signup and view all the answers

Which structure is used to absorb wave energy and protect the coast from coastal erosion?

Breakwater Signup and view all the answers

What is a potential consequence of coastal erosion on agricultural land?

Salty soil and groundwater Signup and view all the answers

Which of the following structures is built to protect against longshore currents?

Groin Signup and view all the answers

What is one method to manage landslide risks mentioned?

Wire mesh installation Signup and view all the answers

Which of the following natural processes contribute to coastal erosion?

Wave action Signup and view all the answers

In which scenario is liquefaction most likely to occur?

During an earthquake Signup and view all the answers

What are retaining walls primarily used for?

To support soil and prevent landslides Signup and view all the answers

Which of the following structures is built on the coast to minimize the impact of storm waves?

Seawall Signup and view all the answers

Which of the following is NOT a cause of flooding?

Wind patterns Signup and view all the answers

What is one effect of flooding on infrastructure?

Collapsing of buildings and roads Signup and view all the answers

Which technique is specifically used to divert excess water during floods?

Diversion canals Signup and view all the answers

How can the risks associated with karsts be minimized during construction?

Geophysical site evaluation Signup and view all the answers

What major incident occurred in February 2007 in Guatemala related to geological risks?

Destruction of infrastructure due to collapses Signup and view all the answers

What dual benefit do dams provide concerning flooding?

Controlling floods and storing excess water Signup and view all the answers

Which of the following is a notable effect of karst formations?

Life loss and economic drain Signup and view all the answers

When was the Shaikha Salama Mosque destroyed due to karst-related issues?

2007 Signup and view all the answers

What are levees designed to accomplish?

Raise river banks to prevent flooding Signup and view all the answers

What environmental condition can lead to the formation of karsts?

Chemical weathering through acid rain Signup and view all the answers

What does the Richter scale measure?

The physical energy produced by an earthquake Signup and view all the answers

What is a primary function of the seismograph instrument?

To record the seismic waves generated by earthquakes Signup and view all the answers

How does the Mercalli scale differ from the Richter scale?

Richter scale measures energy, Mercalli scale measures effects Signup and view all the answers

What is a significant limitation of the Mercalli scale?

It relies on witness descriptions, making it inaccurate Signup and view all the answers

What phenomenon is described as a series of huge waves caused by earthquakes?

Tsunami Signup and view all the answers

What characteristic is true of aftershocks?

They follow a major earthquake and have less energy Signup and view all the answers

Which hazard is associated with ground displacement during an earthquake?

Landslide Signup and view all the answers

Why might two earthquakes of similar energy have different Mercalli scale ratings?

The infrastructure and resilience of the affected areas differ Signup and view all the answers

How does the energy level on the Richter scale change with each magnitude increase?

It increases exponentially by a factor of 32 Signup and view all the answers

Which of the following is NOT a probable hazard associated with earthquakes?

Erosion Signup and view all the answers

Study Notes

Natural Hazards and Risk Management

The course is delivered primarily online by Dr. Dalal Alshamsi from the Geology Department of the College of Science at the United Arab Emirates University.

Outline

Earthquakes and associated hazards (faults, tsunamis, aftershocks, liquefaction, landslides)
Coastal erosion
Floods
Karsts (cavities)
Droughts and desertification
Volcanoes
Risk management of each hazard

Earthquakes (Seismic Activity)

Many large cities (Istanbul, Tokyo, Jakarta) are near plate boundaries, zones of frequent seismic activity.
Over 2 million people died in the 20th century due to earthquakes and associated phenomena.

Earthquake Theory (Elastic Rebound Theory)

When tectonic plates move, stress builds.
If the stress becomes too great, rocks separate (faulting).
An earthquake occurs, and the rock returns to its original shape.

Earthquake Faults

Faults are fractures in rock masses where movement has occurred.

Earthquake Lingo

The focus is the point on a fault where rupture first occurs (subsurface)
The epicenter is the point on the surface directly above the focus.
This data is helpful for earthquake risk management

Earthquake Waves (Seismic Waves)

Body waves (propagate subsurface) include primary (P-waves) which are fastest, and secondary (S-waves).
Surface waves (propagate on the surface) include love and Raleigh waves, traveling the slowest.

Seismograph

Instruments used to record seismic waves.
The seismogram shows the times when P-waves, then S-waves, then surface waves arrive.

Minimizing Earthquake Risk in Surrounding Areas

Speed of seismic waves varies, arriving at different times at observation points.
Calculation of time difference helps determine the distance to an epicenter.
The time it takes for seismic waves to reach surrounding cities can be used to warn populations.

Earthquake Measurement

Richter scale measures earthquake energy (quantified).
Mercalli scale measures earthquake effects on people and buildings (descriptive).
Richter scale measures energy by 32 raised to the power of the magnitude.

Hazards Associated with Earthquakes

Fault: Displacement in rock beds
Tsunami: Series of large waves originating from earthquake epicenter
Aftershocks: Subsequent smaller quakes after a major quake
Liquefaction: Escape of water from aquifers to the surface due to ground shaking, causing damage to buildings.
Landslides: Mass movement of soil and rock due to seismic activity or water/gravity

How to minimize the risk of landslides

Techniques used to reduce landslide risk include wire mesh, concrete cover, and retaining walls.

Coastal Erosion

Human and natural processes shape coastlines.
Wave action is a major natural process.
Human modifications include structures along coastlines.
Coastal erosion can damage structures, cause sea-water intrusion.

Types of Coastal Structures

Seawalls: designed to minimize wave energy and protect coastlines
Breakwaters: structures designed to absorb wave energy
Groins: barriers built into the sea to prevent beach erosion

Floods

Flooding is the submerging of dry land with water.
Causes include heavy precipitation, ground's water absorption capacity, evaporation rates, river bank characteristics, and human modifications to the land.
Effects include loss of life, damage to structures, destruction of crops, collapsing river banks, and release of toxic materials

Minimizing Flood Risk

Techniques include building levees, diversion canals, and dams.
Levees are raised riverbanks; diversion canals redirect flow to a purpose built canal; dams control and store flood waters.

Karsts (Cavities)

Karsts are landforms formed by the chemical weathering of limestone or other carbonate rocks.
They can cause significant problems like collapse of structures and loss of life, creating economic drains
To reduce the risk of karsts formation, geophysical investigations are compulsory for all construction projects in Abu Dhabi.

Droughts and Desertification

Drought is a prolonged period of low rainfall.
Desertification is the process by which fertile land becomes desert.
Human factors like deforestation and urbanization often cause desertification.
Prevention measures should be taken early on.

Volcanoes

Volcanoes are located mainly at convergent plate boundaries.
Risk estimates consider lava viscosity, silica content, temperature, and volcanic ash.
Example volcanoes include Fuji in Japan and Cleveland in Alaska.

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Description

Test your knowledge on geology, focusing on earthquakes, volcanoes, and desertification. This quiz covers key concepts such as the Elastic Rebound Theory and the effects of human activities on the environment. Dive into the scientific explanations for natural phenomena and the risks associated with them.