topic 1: tectonic processes and hazards (ai generated) Flashcards
What theory did Wegner propose in 1915?
Theory of continental drift
Evidence included fossils and plant links between continents and similar rock types in mountains on opposite coasts.
What was the main problem with Wegner’s theory?
He couldn’t explain why the continents drift.
Who proposed the idea that convection in the mantle causes plate movement?
Arthur Holmes.
What significant geological feature did the map of the ocean floor reveal?
The mid Atlantic ridge.
What concept did Harry Hess and Robert Dietz propose in 1960?
Sea floor spreading.
What evidence supported the theory of sea floor spreading?
- Palaeomagnetism
- Age of rock forming on the ocean floor.
What is palaeomagnetism?
The study of the magnetic properties of rocks.
What does the term ‘benioff zone’ refer to?
The active seismic zone on a destructive plate boundary.
What are the three types of plate boundaries?
- Constructive
- Destructive
- Transform.
collision
What is slab pull?
The pulling force exerted by the oceanic plate during subduction.
Where do most earthquakes occur globally?
Most are on the Pacific Ring of Fire.
What are the three kinds of faults?
- Normal
- Reverse
- Strike-slip.
What causes a normal fault?
Tectonic forces that cause the crust to expand and extend.
How do reverse faults differ from normal faults?
Reverse faults cause the crust to shorten and move up.
What is the primary impact of an earthquake?
Ground shaking leading to infrastructure collapse.
What secondary impact can result from an earthquake?
- Landslides
- Aftershocks
- Soil liquefaction.
What scale measures the magnitude of an earthquake?
Moment magnitude or Richter scale.
What does the Mercalli scale measure?
The intensity of an earthquake based on its effects.
What was the magnitude of the 1989 Loma Prieta earthquake?
6.9 on the Richter scale.
What is a tsunami?
A series of waves caused by displaced water during an earthquake.
What does the DART system do?
Detects underwater events that could indicate a tsunami.
What is tephra?
Volcanic ash.
What characterizes a composite volcano?
- Made of alternating layers of lava and ash
- Eruptions are explosive.
What is the Volcanic Explosivity Index (VEI)?
A scale that measures the volume of lava and eruption characteristics.
What determines the type of volcanic eruption?
- Crystal content
- Gas content
- Temperature.
What is the primary hazard of a volcano?
Lava flows.
What is a lahar?
A hot mudslide caused by volcanic activity.
What is the focus of an earthquake?
The underground point where an earthquake originates.
What is the epicenter of an earthquake?
The point on the ground directly above the focus.
What is vulnerability in the context of natural hazards?
The ability to anticipate, cope with, resist, and recover from impacts.
What criteria define a disaster according to Dreggs model?
- More than 10 killed
- More than 100 affected
- State of emergency declared
- International assistance required.
What is declared when more than 10 people are killed in a disaster?
A state of emergency is declared
This indicates the seriousness of the situation and often allows for the mobilization of resources.
What does the Dreggs model of a disaster state?
A disaster occurs when a hazardous natural event affects a vulnerable population, leading to human and/or economic loss.
Define vulnerability in the context of natural hazards.
The ability of an individual or group to anticipate, cope with, resist, and recover from the impact of a natural hazard.
What factors generally increase vulnerability in populations?
- Poverty
- Poor physical geography
- Poor social conditions
What factors can decrease vulnerability?
- Economic wealth
- Insurance
- Scientific research
- Warning and emergency systems
What is the risk equation?
Risk = (hazard × vulnerability) / (capacity to cope)
Name the two main classifications of natural hazards.
- Geographical hazards
- Hydrometeorological hazards
What trend has been observed in the frequency of disasters over time?
The frequency of disasters has increased, but the number of deaths has decreased.
What is a mega disaster?
A large-scale disaster that requires international support and has high impact but low probability.
What is the Disaster Risk Index (DRI)?
A logarithmic scale that compares the number of deaths per million per year against actual deaths from hazards.
What are the components of development that relate to disaster risk?
- Economic component
- Social component
- Environmental component
- Political component
True or False: A strong and stable government can help minimize the effects of tectonic hazards.
True
What does the PAR model illustrate?
The relationship between vulnerability and the impacts of tectonic hazards, highlighting root causes, dynamic pressures, and unsafe conditions.
Fill in the blank: The 2008 China earthquake had a magnitude of ______.
7.6
What was a significant consequence of the 2008 China earthquake related to government corruption?
Government buildings were built to a higher standard than schools, leading to many school children deaths.
What was the magnitude of the Japan earthquake in 2011?
9
What was a major consequence of the Fukushima reactor collapse in Japan?
Japan had to revert to using fossil fuels for energy generation.
What were the conditions in Haiti that contributed to the severity of the 2010 earthquake?
Unstable government, lack of building regulations, and high levels of government corruption.
What is economic leakage?
When money does not stay in a country after a disaster.
What are disaster hotspots?
Countries or areas that are extremely prone to hazards such as cyclones or earthquakes.
What is a multi-hazard zone?
An area that experiences more than one type of hazard, increasing vulnerability.
What is one example of a multi-hazard zone?
The Philippines, known for typhoons, earthquakes, and volcanic activity.
What is risk reduction in disaster management?
Strategies aimed at minimizing the impacts of disasters through preparedness and mitigation.
What does modifying the event in disaster management entail?
Mitigating the impacts of the hazard by reducing its extent or magnitude.
What is hazard mitigation?
Strategies meant to avoid, delay, or prevent hazard events.
What is one method to modify the loss from a seismic event?
Working with insurance companies to protect losses.
What role do NGOs play in disaster response?
They aim for quick response with necessities like food, water, and sanitation.
What does seismicity refer to?
The raw information about how frequently earthquakes affect a particular location.
How can public education help reduce vulnerability?
By teaching communities what to do before, during, and after a tectonic hazard.
Fill in the blank: In 2004, during the Indian Ocean tsunami, local elders instructed villagers to get to higher ground due to unusual ocean movement, resulting in only ______ deaths.
1 out of 200
What is a key focus of the World Risk Index (WRI)?
Assessing how vulnerable areas of the world are to disasters.
What does modifying vulnerability aim to achieve?
To reduce the risk a hazard has on the population.
True or False: Hazard adaptation strategies are designed to avoid hazard events.
False
What is an example of high-tech monitoring used in disaster management?
Mobile phone technology for sending warnings.
What is one way to modify a tsunami hazard?
- Offshore barriers
- Higher sea walls
- Early warning signs
- Mangrove forests
What are hazard resistive building and engineering practices?
Techniques to enhance the resilience of structures against hazards.
What is one method to modify volcanic activity?
Lava diversion barriers.
What is the significance of GIS mapping in disaster management?
It can be utilized in all stages of a disaster to show affected areas.
How can crisis management reduce vulnerability?
By mapping needs and directing aid where it is most needed.
What is the purpose of hazard resistance design?
To modify the event and reduce the impacts of hazards.
