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Tectonic processes and Hazards - Coggle Diagram
Tectonic processes and Hazards
Mega disasters and multiple hazard zones
Tectonic disaster trends
number has remained steady over time although other natural hazards have increased
number of deaths fluctuate with spikes caused by mega-disasters
number of people affected fluctuates but rising slowly
costs fluctuating but rising steadily
Data may not be reliable
e.g. death tolls, may not be collected correctly in developing countries due to inaccessibility to remote areas
in past data not collected at all in many places
methods of collection + definitions of death/damage differ between countries
countries or NGOs may inflate/reduce figures for political reasons
Mega disasters
large scale/impact event, often unpredictable + require significant responses
Have global/regional impact:
may have direct impact upon large area, including more than one country
may affect international supply chains + interdependent economies
secondary environmental effects may cross borders after the event
E.g. Tohoku earthquake:
radiation contaminated water was released into Pacific Ocean from Fukushima nuclear power plant, affecting regional fisheries
all nuclear power plants in Germany closed to perceived risks following meltdown of Fukushima plant
companies in USA reduced production
E.g. Eyjallajökull:
flights cancelled across Europe for weeks due to ash cloud, causing US$2.6 billion loss in GDP + stranding passengers for days
companies (BMW) could not access components -> halt in production
Multiple hazard zones
locations which experience more than one hazard
often, a combination of tectonic hazards with hydrometeorological
hazards can interact with each other to increase risks
sometimes known as disaster hotspots if combined with vulnerable pop -> high level of disaster risk
E.g. Philippines:
floods common due to monsoon rains, typhoons + ENSO -> made worse by climate change
most tsunami prone region in pacific
volcanoes common across destructive margin
100-150 earthquakes occur each year on destructive margin
prone to landslides (mountainous landscape) made worse by deforestation
E.g. Philippines:
Interaction - volcanic ash + typhoon rain mix, creating lahars
Interaction - earthquakes + landslides combine causing mudslides
vulnerability - developing country, 20% pop lives in poverty, with rapid urbanisation + informal settlements (Barong Barongs)
Theoretical frameworks to understand hazards
Frameworks used
used for prediction, assessment of impacts, and deciding how to manage natural hazards include:
prediction + forecasting methods
hazard management cycle
park's model of disaster response
Hazard management cycle
simple model outlines for stage of management before + after a natural hazard strikes used by emergency planners
aim - to reduce impacts + prepare for next hazard
degree of recovery depends on nature of event + level of development of area, as well as governance
Recovery:
rebuilding + getting back to normal over weeks to months
inc restoring services, rebuilding homes, long-term medical care + assisting the economy
will show level of short term economic resilience in a country
Response:
immediate help following hazard - search + rescue, evacuation, emergency shelter, restoration of infrastructure
if effective will save many lives in short term
Preparation:
pre-event activities focused on communities
inc evacuation planning, preparing aid, education + attempts to predict hazards
being aware + prepared for hazard can greatly reduce level of risk, emergency planners are often used at this stage
Mitigation:
identification of potential hazards to minimise impact through planning land use, building codes + hazard defence structures
can be costly + is less effective in developing countries
Park's model
known as hazard response curve - used to compare ability of different countries to recover from hazard over time
Prediction + forecasting accuracy
prediction requires high-certainty judgement, forecasting includes more uncertainty
accuracy of prediction depends on: - type + location of hazard
level of governance + development of country involved
Predicting + forecasting earthquakes
predicting earthquakes is effectively impossible
forecasts can be made using intervals between historic earthquakes in a location
intervals may be regular because earthquake releases strain on plate boundary
Predicting + forecasting tsunamis
only short term forecasts made by analysing buoys for wave height following earthquakes + calc the degree of spatial risk using computer modelling e.g. tsunami early warning systems
Predicting + forecasting volcanic eruptions
monitoring volcanoes can detect changes indicating magma moving to surface
monitoring includes:
water levels + temps, may change with rising magma
increased release of gases, may indicate magma changes
deformation of volcanic cone - occurs as magma is rising, causing bulging
small earthquake activity, increases as magma forces way through rock
Strategies to manage tectonic hazards
Increasing technology
Modify the loss
reduce the losses after the event
easy to put in place, can be costly for developing countries
emergency + ST aid, longer term aid + insurance
Modify vulnerability + resilience
reduce risk to people by reducing their vulnerability + increasing resilience before an event
easier + cheaper for developing countries, requires good governance
high tech monitoring, prediction, education, community preparedness + adaption
Modify the event
reduce danger by changing the hazard itself before + during an event
can be technologically difficult + expensive -> has limited application to developing countries
land-use zoning, hazard-resistant design, engineering defences
Strategies to modify event
Land-use zoning:
areas at highest risk identified + mapped by planners using technology like GIS
the 'red zones' may have restrictions on type + height of buildings, and inc evacuation routes
easy to implement + save lives
low cost
requires high administrative governance to be succesful
relies on modelling
Hazard resistant design:
buildings designed to withstand tectonic hazards + older buildings can be retrofitted, designs include cross-bracing + pendulum weights in high rise blocks, shock absorbing foundations to withstand seismic waves + reinforced roofs for volcanic ash falls
prevents event destroying buildings + infrastructure
existing buildings can be retrofitted
may be expensive, limited to developed countries
requires high tech + strong governance to be successful
Engineering defences:
physical defences can be constructed, e.g. sea walls to withstand tsunamis, attempts also made to divert lava flows using earth barriers
prevents hazard from affecting infrastructure + buildings
reassures the public
may be very expensive, limited to developed countries
high-magnitude events can still overtop or destroy defences
Strategies to modify vulnerability + resilience
High tech monitoring + prediction:
can provide prediction + forecasts to allow for evacuation, Japan e.g. phones activated to repeat 'there is an earthqauke'
provides time for emergency prep + evacuation
monitoring is increasingly remote + forecasts based on more accurate models
forecasts not always accurate can create false alarms
requires high tech + trained scientists to be effective
Education:
earthquake drills take place in many countries
relatively cheap esp for developing countries
may be ineffective with large magnitude events
infrastructure and homes may still be damages
Community preparedness + adaption:
having locally designed evacuation plans + knowledge of landscape + pop means better preparation
relatively cheap for developing countries
provides specific planning for an area
reliant upon community involvement
harder to provide for in remote areas
Strategies to modify loss
Aid:
often provided by NGOs, esp important for less-resilient developing countries
emergency aid provides immediate essentials like food, water, medical care, shelter
ST aid restores essential services like electricity supply
LT aid rebuilds. +supports economy
provides immediate help to vulnerable locations
LT helps reconstruction
may be expensive
often reliant upon foreign donations
possible abuse by corrupt governments
Insurance:
insurers provide economic cover for losses inc infrastructure, homes, + businesses
provides funds for reconstruction + future mitigation
prevents LT damage to economy
Expensive, limited to developed countries
does not prevent loss of life/ damage to buildings + infrastructure
Actions of communities:
local people are vital for search + rescue following a hazard event, especially in remote parts of developing countries
cheap, esp for developing countries
reliant upon community involvement