Tectonics EQ2 Flashcards

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1
Q

What is a natural hazard?

A

A natural hazard is a natural event that has the potential to harm people and their property. A disaster is the realisation of the hazard, i.e. harm has occurred.

UN defines it as ‘a serious disruption of the functioning of a community or a society involving widespread human, material, economic or environmental losses and impacts, which exceeds the ability of the affected community or society to cope using its own resources.
Some large insurers define it as economic losses of over $1.5 million

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2
Q

What is a disaster?

A

Defined by the United Nations Office for Disaster Risk Reduction says: a disaster can be defined as “a serious disruption of the functioning of a community or society involving widespread human, material, economic or environmental losses and impacts, which exceeds the ability of the affected community or society to cope with using its own resources.” They suggest this includes 500 or more deaths.

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3
Q

How can we measure a disaster?

A

The UN suggest this includes 500 or more deaths.

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4
Q

Why are volcanoes less hazardous?

A

This low frequency of destructive events, the slower speed of onset and greater spatial predictability, together with preparedness plans, especially the ability to evacuate, make volcanoes a relatively easier hazard to manage than earthquakes, although still with their particular difficulties.

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5
Q

What is a risk?

A

The probability of a hazardous event causing harmful consequences (loss of life, injuries damage)

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6
Q

What is a hazard?

A

Is the earthquake a volcanic event itself, including relevant secondary hazards, with consideration of the character of the event (such as magnitude, speed on offset, special extent, frequency and duration).

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7
Q

Why is vulnerability important?

A

Modifying vulnerability means increasing the resilience of a community to increase its capacity to cope. In many cases, prediction, warning, and evacuation are used to move people out of harm’s way.

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8
Q

How can we reduce vulnerability?

A

Mitigation means finding ways of being prepared for possible tectonic hazards so that their impacts can be prevented a reduced. Management policies, strategies and actions are needed by governments to minimise vulnerability and reduce disaster risk for all in the community of society. The better the strategies and organisation, the greater the capacity to reduce the risk. Individuals or communities may lack the capacity to make significant improvements on their own, better governance can help reduce vulnerability.

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9
Q

Why is vulnerability a priority?

A

The vulnerability relates to human geography characteristics, such as the location of settlements, knowledge and understanding, the ability to react, resilience, community adaptation and preparedness, and technology for warning systems and protection.

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10
Q

What are the differences in prediction between earthquakes and volcanoes?

A

The prediction of earthquakes remains elusive and Charles Richter wrote that he believed that it will never be possible. One useful predictive tool is estimating the buildup of stress and strain by using the time gaps between earthquakes; this was scientifically successful for Haiti in 2010 and Nepal in 2015. But this method still does not give the precise location or precise time of an event. Volcanoes are constantly monitored by Earth scientists and geologists, working for organisations such as the United States geological survey and the British geological survey. An estimated 500 million people are at risk from volcanic eruptions and probabilities increase because then mineral resources, tourist income, or geothermal energy attract people.

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11
Q

What are the categories of vulnerability?

A
  • Physical vulnerability is when people live in hazard-prone areas in buildings that offer little protection.
  • Economic vulnerability is one people risk losing their jobs, assets and money.
  • Social vulnerability is when a household or community is unable to support the disadvantaged people within it, for example, political isolation exists for the poor, females, elderly and rural residents.
  • Knowledge vulnerability exists when people lack educational training, and there are no warning or evacuation systems in place.
  • Environmental vulnerability exist what are the areas that people are living in has increased hazard risk because of population pressure, forcing people into riskier areas.
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12
Q

What is the hazard risk reduction equation?

A

Mitigation of hazard x reduction in vulnerability/ increase capacity

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13
Q

What is resilience?

A

The ability of a community exposed to hazards to resist, absorb and recover or ‘spring back’ from the effects of a hazard - is determined by the degree to which the community has the necessary resources and is capable of organising itself both prior to and during times of need.

According to the UNISDR, the resilience of a community with respect to potential hazard events is determined by the degree to which the community has the necessary resources and is capable of organising itself both prior to and during times of need.

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14
Q

Why is resilience important?

A
  • Some communities have a high capacity to cope and a high resilience. This means they can reduce the chances of a disaster occurring because:
  • They have emergency evacuation, rescue and relief systems in place.
  • They react by helping each other, to reduce the numbers affected by hazard-resistant design or land-use planning has reduced the numbers at risk.
  • For these communities, the threshold for disaster will be higher than for ones with low coping capacity.
  • Resilience is the ability of a community to cope with a hazard; some communities are better prepared than others so a hazard is less likely to become a disaster. It also includes the ability to return to normal following a disaster.
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15
Q

What is the PAR model?

A

The Pressure and Release Model is used to analyse factors which cause a population to be vulnerable to a hazard. On one side of the model we have a natural hazard itself, and on the other side different factors and processes which increase a population’s vulnerability to the hazard. This vulnerability is often rooted in social processes. These are dynamic and ever-changing and are often unrelated to the hazard itself e.g. poverty, or poor governance.

Suggests what should be tackled in order to reduce the level of risk of disaster, such as root causes, dynamic pressures and unsafe living conditions. It’s based on the idea that a disaster happens when two opposing forces interact.

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16
Q

What is the structure of the PAR model?

A

The PAR model is complex; no two hazards are the same and factors leading to vulnerability are interconnected and hard to measure. If we reduce the social factors affecting a population, we can reduce the pressure they face and so reduce their vulnerability and the effect of natural hazards. The progression of vulnerability is split into three sections. The root causes are often caused by economic, demographic and/or political processes, often affecting large populations or entire countries. Dynamic pressures are local economic or political factors, that can affect a community or organisation and unsafe conditions are the physical conditions that affect an individual (unsafe building, low income, poor health, etc).

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17
Q

What is and what are the common root causes of the PAR model?

A

Vulnerability is a process that starts with root causes. These are political and economic systems that control who has power in society and who has access to resources such as money.

  • Weak Governance
  • Mismanagement by
    Industry, NGOs or IGOs
  • High reliance on products
    easily affected by hazards
    (local agriculture near to
    the hazard, imports by air
    during a volcanic eruption)
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18
Q

What is and what are some dynamic pressures of the PAR model?

A

Through a series of dynamic pressures, these root causes can lead to unsafe conditions. For example, a country that is poor will probably not spend time or money enforcing building codes, which means that buildings may be poorly built. This process from root causes to unsafe conditions- is called the progression of vulnerability.

  • Lack of training/knowledge in locals.
  • Rapid urbanisation
  • Poor communication between the government and locals
  • Natural environment
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19
Q

What is and what are some unsafe conditions of the PAR model?

A

A lack of infrastructure (such as poor sewage management or water supplies) can worsen the impacts of a hazard since it is harder to maintain clean living conditions and avoid the spread of disease following a disaster. A lack of infrastructure would be a factor in unsafe living conditions.

  • Lack of infrastructure (clean water, sewage removal, electricity)
  • Dangerous location of settlements (close to nuclear stations or the natural hazard itself)
  • No warning system for locals
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20
Q

How does the PAR model show impacts of the Haiti earthquake?

A

Root causes:
- Haiti was heavily indebted to US, German and French banks. The Haitian government had to use much of its little available money for debt repayments, rather than improving the country’s infrastructure.
- 80% of the population lives below the poverty line unless then US$2 dollars a day.
- 30 to 40% of the government budget came from foreign aid.

Dynamic processes:
- There was a lack of urban planning to control where and how buildings were constructed, and where people lived.
- There was a lack of disaster preparedness and management systems.
- There was a lack of effective education systems.
- There was rapid urbanisation, which resulted in vulnerable, slum-like housing.
- There was a high population density (in the capital, Port-au-prince, it was 306 people per square kilometre)

Unsafe conditions:
- The soft soil, on which many of Haiti’s buildings were constructed, amplified the seismic waves – increasing ground shaking and damage.
- A lot of illegal housing was built in unsafe areas, such as the hill slides.
- A low GDP per capita of US$1300 meant that buildings were constructed cheaply in quickly, which often resulted in poor-quality environmental structures.
- Before the earthquake, only 39% of Haitians had access to support and 24% to sanitation.

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21
Q

Haiti case study impacts:

A
  • Haiti remains one of the world’s poorest countries.
  • Haiti only had one airport, several ports and a few main roads. When these were damaged, crucial aid supplies were prevented from arriving or being distributed effectively- slowing down the rescue.
  • Over a quarter of government officials were killed, and key government buildings were destroyed, making the governments even less able to organise recovery and relief efforts.
  • In Oct 2010, an outbreak of Cholera occurred and as of 2016, was still ongoing. A lack of medical supplies and trained healthcare workers caused the disease to spread so that by 2015, 9000 Haitians had died and 720000 had been affected.
  • Killed more than 200,000 people and left more than 300 000 people injured.
  • In less than a minute, over a quarter of a million (70%) homes and buildings collapsed, this included 4, 000 schools, 8 hospitals, 75 government buildings and even the presidential palace.
  • The total damage of this tragedy reached an estimated total of $7.8 billion. Also, the majority of Haiti’s agricultural industries were destroyed in the earthquake, causing unemployment levels to skyrocket.
  • Broken electricity cables started fires which damaged woodland areas in Haiti. There were many landslides that occurred that destroyed natural landscapes and blocked off rural areas. Important natural and human landmarks, such as the presidential palace were also destroyed. The earthquake also triggered flooding in coastal areas due to tidal waves.
22
Q

Japan case study:

A
  • 15,894 people died, 6,152 people were injured, 130,927 were displaced and 2,562 people remain missing.
  • A 9m high wave flooded the plant’s generators and electrical wiring. People lost energy immediately.
  • Japan spent billions of dollars building anti-tsunami defences at heights of 12 m. The tsunami washed over them, rendering them totally ineffective.
  • 332,395 buildings, 2,126 roads, 56 bridges and 26 railways were destroyed or damaged. 300 hospitals were damaged and 11 were totally destroyed.
  • Around 4.4 million households in North-East Japan were left without electricity.
  • some coastal areas experienced land subsidence as the earthquake dropped the beachfront in some places by more than 50 cm.
  • Tsunami up to 40 m high devastated entire towns and resulted in the loss of thousands of lives. This caused a lot of damage and pollution up to 6 miles inland.
  • The economic cost was US$235 billion, making this the most expensive natural disaster in world history.
  • The damage caused by the earthquake resulted in the meltdown of seven reactors. Radiation levels at one point were over eight times normal levels.
  • A 250-mile stretch of coastline dropped by 0.6 m, allowing the tsunami to travel further inland.
  • Liquefaction occurred in many of the parts of Tokyo built on reclaimed land. 1,046 buildings were damaged.
  • Geologists estimate that the Pacific plate has slipped westwards by between 20 and 40 m.
23
Q

China case study:

A
  • Initial death tolls ran at 8,700 but this eventually rose to 69,000 with 18,000 people missing two months after the quake.
  • 374,000 people were injured and between 5 million and 11 million people were made homeless.
  • A total of 5 million buildings collapsed; including a number of schools (Juyuan middle school in Dujiangyan city collapsed killing 900 pupils).
  • Other impacts included communications being brought to a halt and the cost of restoring infrastructure was put at $75 million.
  • In Shifang, chemical plants collapsed killing hundreds and releasing toxic ammonia.
  • Power and water supplies were cut and flooding occurred because landslides had blocked rivers.
  • 4.8 million people were made homeless.
  • Public infrastructure collapsed and the provision of utilities was disrupted for an extended period. The economic losses amounted to 845 billion RMB (122 billion USD).
24
Q

What were the impacts of the 2004 Indian ocean tsunami?

A
  • In some coastal villages 70% of the villagers were killed.
  • In Sumatra, 1500 villages were completely destroyed.
  • In Sri Lanka, more than 60% of the fishing fleet and industrial infrastructure were destroyed.
  • In Thailand, the tourism industry lost about US$25 million a month, and 120,000 workers lost their jobs.
  • Ecosystems such as mangroves, coral reefs, forests and some coastal wetlands were severely damaged.
  • Most vegetation and topsoil were removed up to 800 m inland
  • Freshwater supplies in agriculture saw you were contaminated by saltwater

The overall economic cost came to over US$10 billion

Since then, ocean floor earthquake sensors have been installed to trigger early warnings, and many local communities have been trained in evacuation and disaster response.

25
Q

What were the impacts of the Montserrat volcano 1995, 18th July?

A

Montserrat is part of an island arc in the Caribbean sea (formed where the Atlantic plate subducts beneath the Caribbean place). Only 16 km and 10km wide, the island consists of almost entirely volcanic rock. The Soufriere Hills volcano began to erupt huge clouds of ash. Pyroclastic flows also affect much of the island.

  • Dozens of people lost their lives, and more than 7000 moved to other countries.
  • The capital, Plymouth, was destroyed. As the capital, it contained all of the island’s main services such as government offices and hospitals.
  • 2/3 of all houses and 3/4 of all infrastructure were destroyed.
  • Unemployment rose as the island tourist industry collapsed.
  • A lot of farmland was destroyed or abandoned, because it was too close to the volcano – severely affecting agriculture.
  • A top-heavy population pyramid was created, as younger people no longer saw an economic future on the island and moved elsewhere.
26
Q

What are the 4 ways in which tectonic hazards are measured?

A
  • Volcanic explosivity index (VEI)
  • The modified Mercalli scale
  • Moment magnitude scale
  • Richter scale
27
Q

What is the VEI?

A

● Measures the relative explosiveness of a volcanic eruption.
● Based on the height of ejected material and duration of the eruption.
● Scale goes from 0-8 and is logarithmic
(an increase of 1 on the scale indicated a 10 times more powerful eruption).

28
Q

What is the modified Mercalli scale?

A

● Measures the destructiveness of an earthquake.
● It is a relative scale as people would feel different amounts of shaking in different places.
● It is subjective based on if people wake up, if furniture moves, and how much damaged structures receive.
● The scale varies from I to XII
I = Generally not felt by detected on
seismographs XII = Nearly total destruction
● It doesn’t consider economic, social and environmental impacts.

29
Q

What is the moment magnitude scale?

A

● Measures the amount of energy released in an earthquake.
● Scale from 0-9.
● It’s a simple measure, so environmental or social impacts must be inferred.

30
Q

What is the Richter scale?

A

● Measures the amplitude of the waves produce during an earthquake.
● Most widely used scale, as it’s absolute.
● Must infer social or environmental impacts, which can be misleading. The highest Richter scale earthquake readings won’t necessarily be the worst disasters.
● Like the VEI its scale is logarithmic.

31
Q

Why is the MMS scale more accurate than the Richter scale?

A

It uses energy released by all shockwaves as well as area rupture and movement.

32
Q

What is a hazard profile and a criticism of them?

A
  • A hazard profile compares the physical processes that all hazards share and helps decision makers to identify and rank the hazards that should be given the most attention and resources.
  • Hazard profiles are useful for comparing the same hazard in different locations (for example, the Sichuan Earthquake to the Haiti Earthquake).

However, it is difficult to compare different hazards (volcanoes, tsunamis, earthquakes) without a certain degreeof inaccuracy.

33
Q

What are the categories in a hazard profile?

A
  • Magnitude
  • Speed of onset
  • Duration
  • Areal extent
  • Spacial capacity
  • Frequency
34
Q

How can governments use hazard profiles?

A
  • Implement land-use zoning to keep dangerous areas clear.
  • Use hazard-resistant designs – this has had a very positive impact in places which experience lots of earthquakes, such as Chile.
  • Educating local people about what to do in a disaster
  • Ensuring community preparedness
  • Management strategies to manage losses; insurance and aid deployment.
  • They would look at all parts of the profile to plan their responses. For example, to an areal extent, it could help them to plan the scale of the emergency response. Bigger areal scale events such as Sichuan are more difficult to respond to; Christchurch was easier.
  • Remember; the governments can only implement responses they have the economic capacity to afford.
35
Q

Hazard profile for Haiti:

Hazard profile for Christchurch 2011:

A

Magnitude: 7
Speed of onset: Sudden
Areal extent: 120km squared
Duration: Minutes
Frequency: 150-year gap
Spatial predictability: On a known fault
Damage cost: $14bn
Deaths: 300,000

Magnitude: 6.3
Speed of onset: Sudden
Areal extent: 12km squared
Duration: Minutes
Frequency: No previous
Spatial predictability: Fault now known
Damage cost: $40bn
Deaths: 181

36
Q

Hazard profile for Tsunami 2001 (Indian Ocean):

Hazard profile for Tohoku 2011:

A

Magnitude: 9.1
Speed of onset: No warning
Areal extent: Indian Ocean
Duration: Hours
Frequency: Rare (1945 last one)
Spatial predictability: New plate boundary process
Damage cost: $96bn
Deaths: 226,000

Magnitude: 9
Speed of onset: Some warning
Areal extent: Japan’s east coast
Duration: Hours
Frequency: Rare, usually smaller
Spatial predictability: On a known fault
Damage cost: $300bn
Deaths: 20,000

37
Q

Hazard profile for Montserrat 1995:

Hazard profile of Mt St Helens:

A

Magnitude: VEI3 Vulcanian
Speed of onset: Locals not aware
Areal extent: 24km squared
Duration: Years of eruptions
Frequency: First time in 350 years
Spatial predictability: Fixed location
Damage cost: Not known $120m?
Deaths: 19

Magnitude: VEI5 Plinian
Speed of onset: Months of warning
Areal extent: 1300km squared
Duration: Years of eruptions
Frequency: Every 100 years
Spatial predictability: Fixed location
Damage cost: $970m
Deaths: 57

38
Q

California- Issues with the profile?

A
  • Volcanoes on the same chain such as Mount St Helens (which erupted in 1980) are monitored and scientists knew the eruption was going to happen weeks before, not hours.
  • Scientists have predicted for a long time that California will experience ‘the big one’ – an earthquake with a huge magnitude.
  • Over 40 million people live in California and it has a GDP of $2.45 trillion (to put that into perspective, the UK GDP is $2.85 trillion). Over half of this is the service industry which would be hugely disrupted by infrastructure damage.
  • California are also responsible for most of the USA’s domestic food supply, upon which they are hugely dependent. If this was disrupted, the countrywide impact would be vast.
39
Q

What are the ways in which inequalities can influence vulnerability and resilience?

A
  • Wealth levels
  • Education
  • Housing
  • Healthcare
  • Income opportunities
40
Q

How do their wealth levels affect vulnerability and resilience?

A

Their level of wealth influences people’s ability to protect themselves and then recover from a natural hazard. For example, by affecting where they live and the quality of the buildings they live in.

41
Q

How does education affect vulnerability and resilience?

A

People without access to education may be less aware of the risk of a hazardous event and how to protect themselves.

42
Q

How does housing affect vulnerability and resilience?

A

Quality housing is less able to withstand the impact of natural hazards.

43
Q

How does healthcare affect vulnerability and resilience?

A

Communities with poor healthcare suffer more disease and are less able to cope with and recover from a hazard such as food.

44
Q

How do income opportunities affect vulnerability and resilience?

A

Lack of income opportunities means that people cannot buy the resources they need to prepare for or cope with a hazard, and this can affect healthcare and living conditions.

45
Q

How did political, social and economic factors affect Haiti?

A
  • Haiti is a developing country – its poor, and its limited resources were being spent on more immediate issues, such as disease, rather than earthquake preparations.
  • High levels of corruption at both national and local government levels had led to a lack of resources and commitment to improving the country’s infrastructure and living standards.
  • Lack of building controls and regulations meant that many buildings in Port-au-Prince were poorly built slum housing. These buildings could not sustain the ground shaking and simply collapsed.
  • The dense urban environment also made it a difficult place for rescue teams to work.
  • Lack of disaster preparation meant that government officials, police and emergency services just didn’t know what to do when the earthquake struck.
  • Many Haitians were and still living in poverty, so they didn’t have the resources to prepare to cope with the effects of the earthquake.
46
Q

How did the political, social and economic factors affect China?

A
  • In both countries – corrupt government officials often ignored building codes and accepted bribes to allow builders to take shortcuts.
  • The resulting poorly constructed buildings cannot withstand the ground shaking and collapsed.
  • The effects of corruption are particularly evident in Sichuan, with thousands of schools, falling down killing 5335 children, while properly built government buildings nearly remain standing. - China is wealthier than Haiti. It’s a large country with a growing economy so it had the money available to pay for rescue and aid efforts.
  • China’s strong central government was able to respond quickly and effectively to the disaster.
47
Q

How does governance influence in vulnerability and resilience?

A
  • The existence and – especially – the enforcement of building codes and regulations determine the quality and safety of buildings and other structures.
  • Quality of existing infrastructure such as transport and power supplies affected countries’ recovery speed.
  • The existence of disaster preparedness plans influences how quickly and effectively countries respond to and recovers from a hazardous event.
  • The efficiency of emergency services and response teams affects the speed and effectiveness of rescue efforts.
  • The quality of communication systems affects the ability to inform people of a hazard in advance and coordinate rescue efforts.
  • The existence of public education practised hazard responses such as earthquake drills, influences population preparedness.
  • The level of corruption of government officials and businesses influences how resources are used.
48
Q

What are the geographical factors that play a role in vulnerability and a community’s resilience?

A
  • Population density
  • Isolation/accessibility
  • Degree of urbanisation
49
Q

How does population density influence vulnerability and resilience?

A

Highly populated areas may be hard to evacuate, such as the area around Mt Vesuvius in Italy, and are likely to be hit harder by an earthquake.

50
Q

How does isolation/accessibility influence vulnerability and resilience?

A

Often rural areas are hit less hard than urban areas by the initial impact of the disaster, but isolation and limited access can slow the rescue relief effort. The 2005 Kashmir earthquake is a good example.

51
Q

What is the Vanuatu case study?

A
  • In 2015 Vanuatu was ranked as the most at-risk country in the world with earthquakes, volcanoes, tropical cyclones and the impact of sea level rise. This country consists of 65 inhabited islands 1800km northeast of Australia and the Pacific Ocean. It’s in a zone of tectonic complexity with several microplates and subduction of the Australian player under the Pacific plate which forms a volcanic arc.
  • Frequent strong earthquakes, for example, the 7.1MW earthquake in October 2015 which had a focal depth of 130 km. The country is also vulnerable because of isolated islands spread over a large area, women’s groups lacking access to resources, poverty and a stagnant human development of 0.616, undernourishment and little space for people to move into safe locations.
  • Coping capacity is low in many respects as the government is unable to help in times of disaster, relying on outside aid from Australia, New Zealand, the UK in France. Adaptive capacity is low because there is insufficient education, a lack of investment and health care and poor sanitation infrastructure.
52
Q

How does the degree of urbanisation influence vulnerability and resilience?

A
  • When cities are struck by major earthquakes, such as the 1995 Kobe earthquake in Japan or Haiti in 2010, death tolls can be high because of the concentration of at-risk people.
  • Urban areas usually have more assets than rural areas. These include hospitals, emergency services, food stores and transport connections, which increase resilience and coping capacity compared with isolated rural places. However, high population density may mean more people are affected.