Physical geography

Tectonic processes and hazards

Enquiry question 2: Why do some tectonic hazards develop into disasters?

1.4 Disaster occurrence can be explained by the relationship between hazards, vulnerability, resilience and disaster

A natural hazard is a natural occurrence that has the potential to cause harm to persons and property

A disaster is the occurrence of a danger, i.e. harm has happened

It is defined by the UN as "a major disturbance in the operation of a community or society involving extensive human, material, economic, or environmental losses and consequences that exceed the affected community's or society's ability to manage using its own resources."

According to several big insurers, it is defined as economic losses of more over $1.5 million

Because of the following factors, the link between risks, hazards, and persons is complex:

• The unpredictability of the hazard's timing and magnitude, which catches individuals off guard

• A lack of alternatives - those who stay owing to a lack of alternatives (work, lack of space, skills or knowledge)

• Dynamic risks are threats that vary over time and may be influenced by humans

• Cost-benefit

• Fatalism, acceptance of hazards, whatever you do - this is the 'Russian roulette reaction.'

1.6 Development and governance are important in understanding disaster impact and vulnerability and resilience

1.6A Inequality

Population density, length of ground shaking, collateral risks, and reaction are all key considerations. In general, a low degree of development raises the probability of disaster through :

• Population increase

• Urbanisation and suburbanisation

• Degradation of the environment

• Community memory of risks is fading.

• Populations that are either very young or very old

• Inadequate infrastructure and ageing

• Increasing dependency on electricity, water, and communication networks

Mitigating risk

• Warning and emergency-response systems

• Economic wealth

• Government disaster-assistance programmes

• Insurance

• Community initiatives

• Scientific understanding

• Hazard engineering

Vulnerability is frequently high in areas with very low human development (below 0.55) because:

• Even in 'normal' times, many individuals lack basic necessities such as clean water and food

• Many houses are built haphazardly, with no care for hazard resistance

• Disease and sickness are frequent, yet access to treatment is limited

• Because education levels are poor, hazard perception and risk awareness are low

1.6B - Governance and Geographical Factors

The method by which a country or area is administered is referred to as governance. It refers to how a location is managed. Good governance entails national and local governments being effective in keeping people safe, healthy, and educated

Governance efficacy varies greatly and has a substantial impact on coping ability and resilience in the case of a natural catastrophe. The relationship between governance and vulnerability:

Meeting basic needs

• When food, water, and health needs are addressed, the people is physically more prepared to deal with tragedy

Environmental Managament

• Deforestation can exacerbate secondary risks such as landslides. Some risks, such as lahars, can be detected with the proper monitoring equipment

Planning

• Land-use planning can minimise risk by restricting occupancy on high-risk slopes, liquefaction-prone locations, or places inside a volcanic danger zone

Preparedness

• Education and community preparation programmes create awareness and teach people how to prepare, evacuate, and respond in an emergency

Corruption

• Siphoning off funds designated for hazard control, or 'kick-backs,' and bribing officials to enable unlawful or hazardous structures, increases vulnerability a kick-back is an unauthorised payment paid in exchange for assisting a transaction

1.6C - Distaster Context

Major fatality tolls from tectonic risks are uncommon in affluent countries. In terms of magnitude, the 2011 Tohoku earthquake and tsunami in Japan were unique. Japan, the United States, and Chile, for example, have:

• Insurance that is advanced and widely available, helping individuals to recover from disasters (at least in the long term)

• Government-led preparations, such as Japan's annual Disaster Prevention Day on September 1st, as well as public education about risk, coping, response, and evacuation.

• Advanced volcanic monitoring and, when possible, defences such as tsunami barriers

• Controlled local planning systems that employ land-use zoning and construction rules to guarantee structures can resist dangers and are not placed in high-risk locations

Enquiry question 3: How successful is the management of tectonic hazards and disasters?

1.7 Understanding the complex trends and patterns for tectonic disasters helps explain differential impacts

1.7A - Trends

Because tectonic hazards and tectonic disasters are not the same thing, the number of catastrophes has increased while the number of hazard occurrences has remained consistent

Three trends for all disasters:

1. Deaths have decreased over time as a result of improved response management, planning, and, in some situations, prediction. The number of deaths has decreased, particularly since 2000, which might be attributed to greatly enhanced mobile communications to notify people about disasters

• More than 120,000 in 1975 against 90,000 in 1980 (the greatest decline!) 70,000 in 2000 vs. 20,000 in 2015. (a drop of almost 3000 every year)

2. The number of reported catastrophes grew, then stabilised as data coverage and database quality improved. Many disasters in remote locations were unreported for decades. Recently, the number of recorded catastrophes has decreased, implying that fewer hazard events are becoming disasters

• Around 900 in 1975 -> increased to 450 in 2003 -> fell to around 360 in 2012 -> appears to have stabilised

3. Disasters continue to afflict an increasing number of individuals as populations expand and more people reside in high-risk areas

• 55 million in 1975 vs. 190 million in 1995 (most rapid increase) 260 million in 2015 (slower rate of increase)

Trends in tectonic hazards can be summarised as follows:

• Since 1980, the number of earthquake catastrophes has been constant, ranging between 15 and 40 each year

• Earthquake fatalities vary greatly: there were less than 1000 deaths in 2012 and 2014, yet over 200,000 in 2010 and 2004. Overall, earthquake mortality are lower than they were 30-40 years ago, but the impact of singular megadisasters skews the numbers

• Megadisasters are high-magnitude, high-impact, uncommon catastrophes that strike numerous nations (directly or indirectly), resulting in regional or global consequences

• The trend for earthquake economic losses is higher, averaging around $20-40 billion per year, however this is influenced by a small number of major disasters

Economic costs from tectonic disasters are increasing. More wealthier individuals have more property to lose. This is becoming increasingly true in both developing and wealthy countries

1.7C - Multiple Hazard Zones

Multiple hazard zones are locations where two or more natural hazards coexist and, in certain situations, interact to cause complex disasters. California, Indonesia, and Japan are a few examples. These are the locations:

• Are tectonically active, resulting in frequent earthquakes (and frequently eruptions)

• Are geologically young, having landslide-prone mountain zones

• Are frequently on significant storm tracks in the mid-latitudes or tropical cyclone tracks

• Maybe harmed by global climatic disturbances such as El Nino and La Nina

Typhoon Yunga famously hit the area during the 1991 eruption of Mount Pinatubo in the Philippines. The typhoon's heavy rains caused volcanic ash to be mobilised, resulting in devastating lahars. This demonstrates how interconnected hydrometeorological risks might contribute to tectonic disasters

This eruption might have had a far greater impact, but it was properly anticipated, and evacuation kept the death toll to around 850 people. Landslides can be induced by heavy rain on slopes that have already been undermined by seismic vibrations in numerous earthquake-prone locations

A multiple hazard zone with complex hazards is made up of tectonic and hydro-meteorological hazards:

• Earthquakes, volcanic eruptions, tsunamis, and landslides are examples of tectonic risks

• Floods, droughts, storms, and tropical cyclones are examples of hydro-meteorological events

1.8 Theoretical frameworks can be used to understand the predication, impact and management of tectonic hazards

1.8A - Prediction and Forecasting

Prediction entails determining when and where a natural hazard will hit on a geographical and temporal scale that may be meaningfully acted on in terms of evacuation

Forecasting is less exact than prediction and only offers a % chance of danger occurring

Tsunami:

• Can be predicted in parts

• A tsunami caused by an earthquake cannot be foreseen

• Seismometers, on the other hand, can detect and localise earthquakes, while ocean monitoring equipment can detect tsunami in the open sea

• This information may be transmitted to coastal regions, which can then be evacuated

Volcanic eruptions:

• It is possible to forecast

• On volcanoes, sophisticated monitoring technology can assess changes as magma chambers fill and eruptions approach

• Tiltmeters and strain metres detect 'bulging' volcanoes as magma rises, while seismometers detect tiny earthquakes that indicate magma movement.

• Gas spectrometers analyse gas emissions, which can indicate an increased chance of an eruption

• The low mortality toll from volcanic eruptions (despite 60-80 eruptions each year) can be due mostly to considerably improved forecasting of these occurrences

Earthquakes:

• It is impossible to foresee (despite decades of scientific research)

• Only high-risk locations may be recognised (risk forecasting), as well as places prone to severe ground shaking and liquefaction; this information can be utilised for land-use zoning purposes

• 'Seismic gaps,' or locations that have not had an earthquake in a long time and are 'overdue,' can indicate high-risk areas

Tsunami and eruption prediction rely on technology, which must be in place, operable, and linked to warming distribution and evacuation systems

Tsunami monitoring technology was not available in the Indian Ocean in 2004, hence there was no way to warn people on remote shores, despite the fact that there were several hours to do so

1.8B - The Hazard Management Cycle

When feasible, prediction is an important aspect of attempting to control the effects of natural catastrophes. It is, however, not the only approach. The hazard management cycle depicts the many stages of hazard management in an attempt to limit the magnitude of a disaster. It is a cyclical process, with one disastrous experience guiding the planning for the next

1. Response

Immediate assistance in the form of life-saving rescue and aid to keep people alive, as well as emergency shelter, food, and water.

2. Recovery

Rebuilding infrastructure and services, as well as rehabilitating physically and emotionally damaged individuals and their lives

3. Mitigation

Land-use zoning, hazard-resistant structures, and infrastructure are all being implemented to decrease the scope of the next calamity.

4. Preparedness

Community education and resilience, covering how to respond before, during, and after a disaster, as well as prediction, warning, and evacuation technologies and systems

5. (Repeat)

The 'Recovery' Stage of the Hazard Management Cycle may be viewed as the'return to normal' condition. This can happen in a matter of months, but it might take years in rare circumstances. The stage of recovery is determined by:

• The size of the tragedy - larger equals more time

• Lower development level means longer, as poorer people are more seriously affected.

• Governance is important because well-governed areas will direct resources more efficiently toward recovery initiatives.

• External assistance, i.e. aid and funding to aid in the recovery process

1.9 Tectonic hazard impacts can be managed by a variety of mitigation and adaptation strategies, which vary in their effectiveness

1.9A - Disaster Modification

One way of managing a disaster is modifying its impacts. This can be done in three ways:

Modify the event

• BEFORE the danger occurs (long term)

• Reduce the hazard's impact by lowering its areal scope and/or effective magnitude

Modify the vulnerability

• BEFORE the danger occurs (short term)

• Remove individuals from the path of the hazard or assist them in coping with its consequences through fostering resilience

Modify the loss

• AFTER THE HAZARD HITS (short and long term)

• Reduce both short- and long-term losses by assisting with recovery and repair

Land-use zoning:

This is prohibiting people from constructing:

• On low-lying coastal areas (at risk from tsunami and flooding)

• Near proximity to volcanoes

• In regions where there is a greater danger of ground shaking and liquefaction

Lava Diversion:

Lava is diverted and/or slowed using channels, obstacles, and water cooling.

Advantages:

• Diverts lava away from danger

• Relatively cheap cost

Disadvantages: 

• Only works on basaltic lava with a low VEI.

• The vast majority of so-called 'killer' volcanoes are not of this sort

1.9B - Modifying Vulnerability

Community preparedness and education:

Preparation days, instruction in schools, and earthquake kits are examples of this. These are boxes containing vital household items (water, food, a battery-powered radio, and blankets) that are placed in a safe area at home and will be utilised in the days following an earthquake.

Advantages:

• Low-cost solutions are frequently adopted by non-governmental organisations (NGOs)

• Small actions can save lives

Disadvantages: 

• Does not protect property

• Implementation is more difficult in isolated rural areas

Adaptation

• Moving out of harm's path and to a safe location

Advantages:

Both lives and property would be saved

Disadvantages:

• It is impossible due to high population concentrations

• People's traditional houses and rituals are disrupted

Hi-Tech Scientific Monitoring (used for Prediction)

This is used to influence volcanic behaviour and anticipate eruptions

Advantages:

• In most circumstances, it is feasible to forecast an eruption

• Life is saved as a result of warnings and evacuations

Disadvantages:

• Because monitoring volcanoes in underdeveloped countries is expensive, not all of them are monitored

• If forecasts are not correct, you may have 'cry wolf syndrome.'

• When forecasts (and evacuations) are incorrect, people are less likely to accept the following one

• Does not protect against property damage

1.9C - Modifying Loss

Loss modification might be defined as 'picking up the pieces' after a calamity. If event and vulnerability modification are employed, losses should be minimal; nonetheless, loss modification is frequently the primary management technique in underdeveloped nations. This was the situation during the 2010 Haiti earthquake and the 2004 Indian Ocean tsunami, both of which occurred after management failed to safeguard people

Short-term Emergency Aid:

Rescue and search operations are followed by emergency food, water, and shelter.

Advantages:

Reduces the number of deaths through saving lives and keeping people alive until longer-term assistance comes.

Disadvantages:

• Expensive

• It is difficult to deliver in remote places

• In impoverished nations, emergency services are few and inadequately prepared

Long-Term Aid

This might take the shape of rebuilding plans to rebuild a region and perhaps increase resilience

Advantages:

Reconstruction may 'instil' resilience through better land-use planning and building approaches

Disadvantages

Expensive:

After the first calamity, the media rapidly forgets about the needs

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Insurance

This is money provided to people to compensate them for their losses.

Advantages:

• Allows people to recover economically by covering the costs of reconstruction

Disadvantages:

• It doesn't save lives

• In the developed world, few individuals have insurance