tectonics

Question 1

where do most earthquakes occur

Answer 1

• along the boundaries of plate tectonics, with the highest magnitude being at subduction zones

Question 2

3 types of plate boundary

Answer 2

convergent - towards eachother, subduction zones or when two plates bash into eachother and the crust is forced upwards
divergent - away from each other
conservative - alongside eachother

Question 3

where are the most volcanos found

Answer 3

75% along the ring of fire in the pacific, found ta convergent or divergent zones, and can also be found inside plates (intraplate volcanism)

Question 4

where do tsunamics occur the most

Answer 4

70% found in the pacific region and caused due to the activity from convergent o divergent plate boundaries

Question 5

what is alfred wegners theory of continental drift

Answer 5

he believed that all land once formed a giant landmass named the supercontinent ‘pangea’ and have since drifted to their current positions due to tidal forces caused by the moon’s gravity or the Earth’s rotation.
Wegener pointed to the similarity of fossil types found on continents that are now widely separated by oceans
Wegener also cited similar geological formations found on continents now separated by oceans
the “fit” of the continents. He noted that the coastlines of continents like South America and Africa seemed to fit together, as if they had once been joined

Question 6

what is harry hess’ theory of seaflood spreading

Answer 6

Sea-floor spreading suggests that the ocean floors are constantly moving and that new oceanic crust is being created at mid-ocean ridges, where tectonic plates are diverging. As new crust forms, it pushes the older crust away from the ridge, causing the sea floor to spread outward and a gradual widening of the seafloor basin.
Magnetic Stripes on the Ocean Floor = Scientists found that the Earth’s magnetic field had reversed many times in the past (geomagnetic reversals), and these reversals were recorded in the oceanic crust as symmetrical patterns of alternating normal and reversed magnetic polarity. These magnetic “stripes” are found on both sides of mid-ocean ridges, indicating that the sea floor is spreading symmetrically away from the ridge.

Question 7

what is paleomagnetism

Answer 7

Scientists found that the Earth’s magnetic field had reversed many times in the past (geomagnetic reversals), and these reversals were recorded in the oceanic crust as symmetrical patterns of alternating normal and reversed magnetic polarity. These magnetic “stripes” are found on both sides of mid-ocean ridges, indicating that the sea floor is spreading symmetrically away from the ridge. the iron minerals in magma align with the earth magnetic field, and when the earth’s magnetic field flips, so do the direction the iron minerals are facing. divergent plate boundaries.

Question 8

what is the theory of mantel convection

Answer 8

The Earth’s interior is hot, and the heat from the core causes the mantle material to rise, cool, and sink in a cyclical process. This movement creates convection currents, which are the main driving force behind the movement of tectonic plates in the lithosphere at the Earth’s surface. molten rock heates and rises at the earths core and when it reaches the earths crust it is forced sideways and cannot pass through the rock.

Question 9

what is the theory of slab pull

Answer 9

subducting oceanic plate pulls the rest of the tectonic plate along with it as it sinks into the Earth’s mantle at a subduction zone. As the dense, cold oceanic crust sinks into the mantle, it exerts a pulling force on the rest of the plate.

Question 10

what is the theory of ridge push

Answer 10

the force exerted by the elevated position of the mid-ocean ridges, where new oceanic crust is created, pushing the tectonic plates away from the ridge. This force helps to drive plate movement at divergent boundaries, where tectonic plates are moving apart.

Question 11

what is the benioff zone

Answer 11

a region of the Earth’s interior where subducting tectonic plates undergo intense earthquake activity as they sink into the mantle, it creates a zone of earthquakes that can be observed along a sloping plane beneath the Earth’s surface.

Question 12

charecteristics of a conservative plate boundary

Answer 12

lateral movement
high intensity and shallow earthquakes
volcanic activity isnt common

Question 13

charecteristics of a divergent plate boundary

Answer 13

low magnitude earth quakes
creation of new, basaltic rock
up-welling of mama causes an atlantic ridge

Question 14

charecteristics of a convergent plate boundary

Answer 14

bnioff zone at subduction
fold mountains and deep sea trenches
most powerful volcanic eruptions

Question 15

what are p waves

Answer 15

primary waves
the first wave to occur during an earthquake
they’re the fastest and highest frequency but create little damage e.g. vibrations only

Question 16

what are s waves

Answer 16

secondary waves
second to occur and create more damage than p waves but not as much as love/rayleigh waves
slower and shorter frequency
create a lateral movement of the ground

Question 17

what are l waves

Answer 17

love and rayleigh waves
lasyt to arrive and the slowest, but cause the most damage
they focus their energy on the earths surface and only occur in the lithosphere
love waves = up and down/side to side
rayleigh waves = up and down/ side to side/ circular motion

Question 18

secondary hazards of earthquakes

Answer 18

• Landslides = The shaking of the ground can trigger landslides in hilly or mountainous areas. can bury buildings, roads, and infrastructure, causing additional casualties and disruptions.
• Fires = Gas lines may rupture, electrical lines may be damaged, or flammable materials may be ignited by the shaking. Fires can spread rapidly, especially in densely populated areas, exacerbating the destruction and causing further casualties.
• Flooding = Earthquakes can damage dams or water supply systems, leading to flooding in areas that were previously protected. Floods can destroy property, disrupt communities, and cause long-term environmental damage. Floodwaters can also carry debris and contaminants, further increasing the risk to public health.
• Aftershocks = smaller earthquakes that occur after the main earthquake event, sometimes lasting for days, weeks, or even months. can cause further damage to already weakened buildings and infrastructure. They pose a continued risk to people, especially those who have already been affected by the primary earthquake.
• Economic Disruption = can disrupt local and regional economies by damaging businesses, transportation networks, and essential infrastructure. The economic costs of earthquakes can be long-lasting, with regions facing high recovery costs and disruptions in supply chains, transportation, and production. Long-term unemployment and economic instability may follow, especially in severely affected areas.
• Public Health Issues = can disrupt public health services, contaminate water supplies, and cause injury or illness. The destruction of hospitals, clinics, and other health facilities can make it difficult to treat the injured. Disruptions to clean water supply systems can lead to the spread of diseases, particularly in areas with poor sanitation infrastructure.

Question 19

primary hazards of earthquakes

Answer 19

• Ground Shaking = The most common and immediate effect of an earthquake is the shaking of the ground. The intensity of the shaking depends on factors like the earthquake’s magnitude, depth, and proximity to populated areas. can cause buildings, bridges, roads, and other structures to collapse, leading to widespread damage and casualties.
• Surface Rupture = the movement of the Earth’s crust along a fault line breaks through the surface. can crack roads, pipelines, and other infrastructure. It may also damage buildings directly along the fault line.
• Ground Liquefaction = In areas with loose, water-saturated soil, the shaking from an earthquake can cause the ground to behave like a liquid. can cause buildings and other structures to sink or collapse, as the ground loses its ability to support weight.
• Tsunamis = Earthquakes that occur under the ocean can trigger tsunamis—large sea waves generated by the displacement of the ocean floor. can flood coastal areas, causing widespread destruction, loss of life, and significant economic damage. They can travel over vast distances, affecting regions far from the earthquake’s epicenter.

Question 20

primary affects of volcanoes

Answer 20

• Lava Flows = molten rock that is expelled during an eruption. It can flow down the sides of a volcano, destroying everything in its path.
  can destroy buildings, roads, crops, and infrastructure.
• Pyroclastic Flows = fast-moving currents of hot gas, ash, and volcanic debris (tephra) that can travel at high speeds down the slopes of a volcano. one of the most dangerous aspects of volcanic eruptions, as they can destroy entire towns, cause fatalities, and leave areas uninhabitable for long periods. They are extremely hot and can devastate large areas in a very short time.
• Ashfall = volcanic ash (fine, powdered rock) is ejected into the atmosphere and falls back to Earth, sometimes hundreds of kilometers away from the eruption site. can cause respiratory problems, contaminate water supplies, damage crops, collapse roofs under the weight of the ash, and disrupt transportation (blocking roads and airports). It can also lead to long-term environmental damage.
• Lahars = mudflows formed when volcanic ash, water, and debris mix to create fast-moving flows of mud and debris. can bury settlements, roads, and farmland. They are particularly dangerous in the rainy season when ash deposits mix with water from rain or melting snow

Question 21

secondary affects of volcanoes

Answer 21

• Climate Change (Global Cooling) = The particles and gases can reflect sunlight, leading to a cooling effect on the Earth’s climate. This is known as volcanic winter. The cooling can reduce global temperatures by several degrees, disrupt agriculture, and affect food supply.
• Air Travel Disruptions = Volcanic ash clouds can reach high altitudes and spread over large areas. These clouds can cause significant disruptions to air travel.
• Water Contamination = Ash and chemicals from volcanic eruptions can contaminate water sources, especially in nearby rivers, lakes, and groundwater. Contaminated water supplies can lead to health problems, including the spread of waterborne diseases.
• Economic Losses = Local economies can be severely impacted, especially in areas that depend on agriculture or tourism. The rebuilding costs and lost revenue can take years to recover from.
• Health Impacts = The effects of volcanic ash and gases can have serious health implications for people and animals. Inhaling volcanic ash can cause respiratory issues, eye irritation, and long-term lung damage. Sulfur dioxide released by eruptions can also cause acid rain, which may lead to skin irritation, water contamination, and damage to crops.

Question 22

what is the Pressure and Release model

Answer 22

focuses on how vulnerabilities and hazards interact to create a disaster
the ‘pressure’ comes from 3 models:
1. root causes = socio-political and economic factors that create or perpetuate inequality and vulnerability e.g. poverty, inequality, political power structures, environemental degregation
2. Dynamic Pressures = intermediate causes that result from the root causes and exacerbate vulnerability e.g. lack of awareness/education , poor infrastructure
3. Unsafe Conditions = specific conditions and vulnerabilities that arise in the local context e.g. poor housing

Release refers to the ways in which the pressure (vulnerability) is either reduced or managed
- Disaster Mitigation = reduce vulnerability before a disaster strikes e.g. Improving building standards, Creating early warning systems, education and training
- Disaster Preparedness and Response = planning, training, and resource allocation before a disaster occurs. e.g. developing emergency plans, practicing evacuation drills, and setting up emergency response systems.
- Response = the immediate actions taken during and after a disaster to reduce its impacts. e.g. Rescue operations
- Resilience Building = (resilience refers to a community’s or system’s ability to bounce back from a disaster.) e.g. Strengthening community networks, Empowering communities to take charge of their own risk management through participation and awareness programs.

Question 23

what is the modified mercalli scale

Answer 23

an intensity scale to measure the intensity of an earthquake based on its observed effects on people, buildings, and the Earth’s surface, rather than the actual energy released by the earthquake
MMI scale ranges from I to XII
I (Not felt): Earthquake not felt except by a very few under especially favorable conditions
XII (Catastrophic): Total destruction of everything; the ground may be visibly altered, with large-scale liquefaction or other catastrophic ground effects.

Question 24

what is the moment magnitude scale

Answer 24

calculates the magnitude by considering the total energy released during an earthquake. It takes into account the following factors:
The area of the fault that slipped (the fault length and width).
The amount of slip along the fault (how far the ground moved).
The properties of the rocks involved (how easily the rocks break or deform).
it is a linear scale of 1-10 where each whole number increase on the scale represents a tenfold increase in the amplitude of seismic waves and approximately 32 times more energy released

Question 25

what is the volcanic explosivity scale

Answer 25

scale ranges from VEI-0 to VEI-8, with higher numbers representing more explosive and larger eruptions, VEI is logarithmic, meaning that each interval represents a tenfold increase in eruption size and a roughly 1,000-fold increase in erupted material.
VEI-0 (Non-explosive): Small eruptions with little to no ash column, often lava flows or gentle eruptions
VEI-8 (Mega-colossal): Catastrophic eruptions, with more than 1,000 cubic kilometers of material erupted. These are extremely rare and have global impacts

Question 26

how does economic inequality influence vulnerability and resiliance

Answer 26

Economic Inequality
Limited Resources for Protection: People with lower income or living in poverty often lack the resources to build or maintain safe housing or infrastructure = more likely to collapse
Access to Insurance: Wealthier individuals and communities are more likely to have access to insurance or financial support that can help with recovery after a disaster. In contrast, low-income people may not have access to such resources, leaving them more vulnerable to long-term economic loss.
Lack of Preparedness: Those with fewer financial resources often cannot afford disaster preparedness measures.

Question 27

how does social inequality influence vulnerability and resiliance

Answer 27

Social Inequality
Unjust Access to Information: Vulnerable populations, such as marginalized communities, ethnic minorities, or people in remote areas, may not have access to crucial information about earthquake or volcanic risks. This lack of knowledge can result in slower responses to early warnings and less effective evacuation or protective actions.
Education and Training: People with lower levels of education may be less informed about risk reduction strategies or how to act in the event of a disaster.
Social Networks: People in higher social strata may have better access to emergency networks, social support, and organized community responses. Those in disadvantaged communities may lack these networks, making it harder to coordinate rescue and relief efforts.

Question 28

how does geographic inequality influence vulnerability and resiliance

Answer 28

Geographic Inequality
Living in Hazardous Areas: The poorest communities often live in more hazardous areas, such as on unstable slopes near volcanoes, in poorly constructed informal settlements, or in earthquake-prone zones. These locations may be chosen due to economic necessity, as land in safer areas may be more expensive or inaccessible.
Inadequate Infrastructure: Wealthier regions often have more robust infrastructure, such as better roads, bridges, and communication systems, which are crucial for disaster response and recovery. In contrast, poorer areas may have weak or outdated infrastructure that can collapse more easily during an earthquake or be disrupted during volcanic eruptions.

Question 29

how does political inequality influence vulnerability and resiliance

Answer 29

Political Inequality
Neglect in Disaster Planning and Response: Disadvantaged groups or regions may be politically marginalized, leading to their exclusion from disaster preparedness planning and response efforts. Governments may allocate more resources to wealthier, more politically influential regions, leaving vulnerable populations with insufficient support before, during, and after a disaster.

Question 30

how does governance influence a communities resiliance

Answer 30

1. Disaster Preparedness and Planning
   Policy Development: Good governance ensures that comprehensive disaster risk reduction policies are in place. These plans can guide preparedness efforts, including evacuation routes, emergency shelters, early warning systems, and strategies for protecting critical infrastructure.
   Risk Assessment: help identify areas most vulnerable to disasters
2. Resource Allocation and Funding
   Adequate Investment: Governments that prioritize disaster risk reduction and resilience allocate necessary resources for mitigation measures, such as strengthening buildings, improving infrastructure, and ensuring emergency services are well-equipped.
3. Emergency Response and Coordination
   Efficient Response: Well-organized governance structures facilitate quick and efficient responses during and after a disaster. This includes coordinating rescue operations, providing first aid, and delivering essential services like food, water, and medical care.
   Communication Systems: A transparent and well-communicated governance system ensures that citizens are informed about potential risks and know how to act during emergencies.
4. Recovery and Rehabilitation
   Post-Disaster Recovery Plans: Governance impacts how a community recovers after a disaster. Effective recovery policies provide a roadmap for rebuilding infrastructure, restoring livelihoods, and supporting mental health and community cohesion.
   Long-Term Resilience Building: Recovery should not only focus on returning to pre-disaster conditions but also on building back better. Good governance can guide efforts to improve infrastructure, diversify livelihoods, and incorporate disaster-resilient practices in the reconstruction process.
5. Community Engagement and Participation
   Inclusive Decision-Making: Resilience is strengthened when communities are actively involved in disaster planning and decision-making. Good governance encourages public participation, allowing citizens to voice concerns and contribute local knowledge. This ensures that plans are more relevant and effective.
   Empowerment of Vulnerable Groups: Governance that prioritizes inclusivity supports the empowerment of vulnerable groups (e.g., women, children, elderly, people with disabilities) by ensuring they are involved in resilience efforts and have access to the resources they need.
6. Strengthening Institutions and Governance Structures
   Institutional Capacity: Effective governance involves the establishment of well-trained, capable institutions that can handle disaster risk management. This includes local emergency services, public health systems, and regulatory bodies responsible for enforcing building codes, land use planning, and environmental protection.
   Accountability and Transparency: Strong governance ensures that decision-makers are held accountable for their actions, particularly in terms of disaster preparedness, response, and recovery. Transparency in resource allocation and spending reduces corruption and ensures that funds are used effectively.
7. Legislation and Regulation
   Building Codes and Land Use Regulations: Governance influences the establishment and enforcement of building codes, land-use regulations, and environmental protections that minimize disaster risks. For example, earthquake-resistant building codes can prevent collapse during seismic events, while land-use planning can prevent settlement in high-risk areas like floodplains or near active volcanoes.
   Environmental Management: Governance can also play a role in mitigating environmental risks, such as deforestation or poor land management practices, which can increase vulnerability to landslides, flooding, or volcanic eruptions. Sustainable environmental policies contribute to overall resilience.
8. Social Cohesion and Trust
   Building Social Capital: Effective governance helps build trust between citizens and institutions, fostering a sense of community and social cohesion. Resilient communities tend to have strong social networks, where people help one another in times of crisis. Good governance strengthens these networks by promoting collaboration and mutual support.
   Trust in Authorities: Trust in government institutions is crucial for resilience. When people trust that authorities are working in their best interests and that relief will be provided during a disaster, they are more likely to follow safety instructions and participate in recovery efforts.
9. International Cooperation and Support
   Global Partnerships: In some cases, disaster resilience requires international cooperation, especially for large-scale events. Effective governance ensures that a country can collaborate with international organizations, neighboring nations, and humanitarian agencies to access resources, knowledge, and aid.
   Disaster Risk Financing: Strong governance structures can also enable access to international disaster risk financing mechanisms, such as insurance, loans, and grants, that provide financial support during times of crisis.
10. Climate Change Adaptation
    Integrating Climate and Disaster Risk: Good governance can integrate climate change adaptation with disaster risk reduction. As climate change increases the frequency and intensity of natural hazards, effective governance ensures that communities are prepared for evolving risks, such as more intense volcanic activity or earthquakes exacerbated by climate-related factors.