EQ2- Why do some tectonic hazards develop into disasters?

Natural hazard vs disaster

Natural hazard: a natural event which has the potential to cause harm to the environment, people or the economy.

Disaster: when harm actually occurs to the environment, people, or economy, disrupting the functioning of a community + exceeding its ability to cope using its own resources.

Vulnerability

How susceptible an area is to damage from a particular hazard event.

Factors affecting vulnerability

Physical

size of hazard: the larger, the more vulnerable

location: hillside houses more vulnerable to landslides, collapse

Human

pop. density: more ppl in disaster zone

economic development: affect education, quality of buildings + infrastructure

governance: organised + well-structured gov/ communities can help vulnerable

What is the hazard risk equation + what does it tell?

Tells us about an areas resilience (capacity to withstand/ recover quickly from an event).

-explains why events can have similar magnitude but different impacts e.g. 9000 dead in Nepal 2015 earthquake compared to 2 ppl in NZ (2016)

Factors affecting resilience

Level of corruption- money goes to where it is intended

Education- people educated about risks + actions to take

Infrastructure- quality

Healthcare- well-equipped staff

Pressure and Release (PAR) model

Pressure model

Root cause: related to resources, decision-making + governance

Dynamic pressures: relate to education, urbanisation, pop change

Unsafe conditions: poor quality housing+infrastructure, poverty

Release model

Shows how vulnerability can be reduced + resilience increased by addressing safety, reducing pressures, addressing root causes, hazard mitigation

Examples of PAR model in Haiti 2010

Root cause→dynamic pressure→unsafe conditions

Haiti is poor (GNI $660) → There is no investment in urban planning → only 39% have safe access to drinking water, making the pop vulnerable to disease

Natural increase is 16/1000 → rapid urbanisation → large no. of illegal unsafe shanty settlements

What is a tectonic hazard profile?

Compares tectonic hazard events, allowing a better understanding of the nature + risks of the hazards.

Advantages + disadvantages of hazard profiles

+can be used to plan for future events

+useful when comparing: same hazards with diff vulnerabilities e.g. earthquake in developed vs developing country, same hazard with diff processes e.g. volcano on constructive vs destructive boundary.

-other factors may have a greater influence on the impact

-they focus on physical factors when human factors may be more important

-subjective

-multi-hazard events are not easily represented

Impacts of volcanoes developed vs developing

Eyjafjallajökull vs Merapi

Eyjafjallajökull 2010	Merapi 2010
no injuries/ deaths 700 evacuated flooding caused by ice melt flight disruptions for 10M ppl, costing est. £130M a day Led to short-term climate change of -0.5°	353 dead 300k evacuated sulphur dioxide caused breathing problems, skin irritation £13M worth of crops destroyed food price rose soil erosion due to destruction of vegetation

Pop. density, no. of settlements, pyroclastic flow was higher in Merapi

Hazard profile (volcano)

Eyjafjallajökull vs Merapi

	Eyjafjallajökull	Merapi
magnitude speed of onset duration areal extent frequency spatial prediction	VEI 4 abrupt months to N America+ Asia rare predicted	VEI 4 rapid weeks to Singapore, Malaysia ash cloud frequent(4-5yrs) predicted

Governance + development

Eyjafjallajökull vs Merapi

Iceland

• GOV: well-coordinated + efficient response/ management due to previous volcanic experience.

• DEV: strong infrastructure, quick recovery of tourism sector, strong crisis management system, one of the best healthcare systems in the world

Indonesia

• GOV: centralised disaster management + local level were relatively robust with evacuation challenges, but isolated rural areas had weak infrastructure

• DEV: rural+less developed areas had poor infrastructure +heavy reliance on agriculture.

Impact of Earthquakes developed vs developing

Japan vs Haiti

Japan 2011 9 magnitude	Haiti 2010 7.1 magnitude
16k dead $220bn cost (0.03% of GDP) 4.4M households were left with no electricity Impact on global supply chain in technology led to nuclear disaster which contaminated marine life with radioactive water	300k deaths $14bn damage costs (116% of GDP) Put Haiti in a cycle of dependence on international aid deforestation- as displaced ppl relied on natural resources for survival

Hazard profile (earthquake)

Japan vs Haiti

	Japan 2011	Haiti 2010
magnitude speed of onset duration areal extent frequency spatial prediction	9 rapid 6 mins 70km2 rare known subduction zone	7 sudden minutes 120km2 150yr gap known fault

Governance + development

Japan vs Haiti

Japan

• GOV: highly developed disaster preparedness systems coordinated at regional, national+local levels allowed for quick evacuations+response.

• DEV: advanced infrastructure + healthcare, allowed for quick recovery

Haiti

• GOV: political instability + weak institutions- slow + poorly coordinated response

• DEV: poverty+social inequality, underdeveloped infrastructure + rural areas, dependent on foreign aid.

Impact of tsunami developed vs developing

Japan 2011 vs Chile 2010

Japan 2011 9 magnitude	Chile 2010 8.8 magnitude
16k dead damage cost of 4% of GDP Fukushima nuclear disaster that followed led to reliance on fossil fuels damage to mangroves, salt marshes, beaches	800k affected damage cost of 18% GDP water-borne disease contaminated drinking supplies fishing industry affected which many relied on as primary income pollution to marine env.- oil spills, contaminated runoff

Hazard profile (tsunami)

Japan 2011 vs Chile 2010

	Japan 2011	Chile 2010
magnitude speed of onset duration areal extent frequency spatial prediction	9 no warning hours east coast rare known subduction zone	8.8 15-30mins hours across pacific ocean low predicted

Governance + development

Japan 2011 vs Chile 2010

Chile

• GOV: strong national disaster management + coordination helped rapid response, however local communication + evacuation were poor.

• DEV: resistant infrastructure + strong economy, however there are regional inequalities + lack of infrastructure in rural areas.

What does magnitude measure + how can it be measured?

Measures the energy released at the source (focus).

Moment magnitude scale (MMS)

Goes from 1 (not felt by humans) to 10 (greatest impact)

• logarithmic scale (6 MMI is 10x greater than 5)

Earthquake intensity + how it can be measured

Intensity is the severity of ground shaking at a particular place based on the effects on humans, buildings and the environment.

Modified Mercalli Scale

Scale goes from I (not felt) to XII (environment destroyed)

Measuring volcanic eruptions- Volcanic Explosivity Index (VEI)

Measures the size of an eruption.

• logarithmic scale from 0-8

Calculated based on:

height of material ejected into atmosphere

volume of material

duration of eruption

How can inequality influence vulnerability + resilience?

(+ its link to development)

Lack access to: education, housing, healthcare, income.

Reflected through HDI:

• low education levels- ppl have lower awareness of the risk + less perception of the hazard

• poor quality housing- unregulated building + use of poor construction materials

• lack of access to healthcare

• poor access to clean water + healthy diet

How development affects vulnerability + resilience Nepal 2015 earthquake Case Study

• one of the poorest countries in the world- lack of funds for preparation and planning

• buildings poorly constructed; although there were building regulations these were usually not enforced

• gov corruption meant infrastructure + planning lacked investment

Governance

The way in which a country is run.

How does governance influence vulnerability +resilience?

Weak governance leads to increased vulnerability + impacts ability to to cope with a hazard event:

• planning for hazards using hazard mapping + land use zoning

• educating pop. about risks + how to best protect themselves

• predicting events as they don’t have technology + equipment available

• preparing by ensuring stocks of water, food, shelter, medical equipment is available

How does corruption impact vulnerability + resilience?

• money not spent on preparation

• construction companies get around building regulations or land use zoning by bribing officials

e.g. Turkey corruption related to construction led to increased deaths in 2023 earthquake

How do geographical factors influence vulnerability + community resilience?

Pop. density

• makes it harder to evacuate

• buildings more tightly packed- larger impact if collapses

Accessibility/ isolation

• ppl less likely to have methods of communication

• difficult to supply aid e.g. Nepal 2015- some rural places were not reached for days

Urbanisation

• higher concentration of ppl + buildings

• large no. of poorly constructed houses on steep slopes are particularly vulnerable