mitigating effects of volcanic eruptions Flashcards
3Ps to reduce a community’s vulnerability towards threats posed by natural hazards
prediction
- scientists can monitor volcanoes to try and estimate when they are likely to erupt as volcanoes provide warnings before an eruption
prevention
- removing the people most at risk from tectonic hazards is vital in reducing vulnerability
preparedness
- governments and organisations can help reduce the vulnerability by actively trying to enhance people’s preparedness and capacity to cope with volcanic hazards
how many prediction strategies used to predict volcanic eruptions
9
prediction strategies used to predict volcanic eruptions
seismometers, tiltmeters, satellites, infrared camera imagery, thermal imaging, spiders, measuring temperature, looking at previous eruptions to identify patterns, observations of noticeable precursors to eruptions
how are seismometers used to predict volcanic eruptions
- part of the seismograph (a pendulum or mass)
- suspended mass tends to stay still due to inertia when the ground moves
- recording pen records relative motions
- convert ground vibrations due to seismic waves into electric signals
how are tiltmeters used to predict volcanic eruptions
- detect subtle changes on the slopes of the volcano (increasing steepness can mean build-up of gases, which could signal an upcoming eruption)
how are satellites used to predict volcanic eruptions
- detect changes in the shape of volcano and areas with active lava flow or ash plumes
how is infrared camera imagery used to predict volcanic eruptions
- detects and measures infrared energy of thick volcanic fumes
- provides a clear view of hot, warm, and cool surfaces of a volcano
- limitation: cannot go through water or glass
how is thermal imaging used to predict volcanic eruptions
- uses camera to monitor heat sources within crust or volcano
- swelling and heating of the ground are both signs of impending eruptions
example of thermal imaging being used to predict volcanic eruption
In 2000, an eruption of the Hekla volcano in Iceland was predicted based on temperature measurements through thermal imaging. A sudden increase in the ground temperature around the volcano was detected, indicating the intrusion of magma. This prompted authorities to close the area to the public and issue warnings, thus saving many lives.
how are spiders used to predict volcanic eruptions
- monitor the gases escaping from a volcano
- there is an increased release of sulphur dioxide as magma gets closer to the surface, indicating an eruption
how is looking at previous eruptions and identifying patterns used to help predict volcanic eruptions
through looking at the past history of eruptions, scientists can identify patterns of activity and predict eruptions
example of looking at previous eruptions and identifying patterns being used to predict a volcanic eruption
in mt. fuji in japan, geological research revealed patterns in eruptive history including intervals between eruptions and types of eruption. tephra layers in nearby lakes studied to suggest previous eruptions, enabling scientists to identify periods of rest and activity
how does observing noticeable precursors to eruptions help predict a volcanic eruption
- identify physical factors that indicate an impending eruption
example of observing noticeable precursors to eruptions which helped predict a volcanic eruption
In 1991, scientists surveyed Mount Pinatubo by helicopter and noted new gas vents, indicating an impending eruption. This allowed them to make a good estimate of the area that needed to be evacuated thus saving many lives
prevention strategies used to protect against a volcanic eruption
hazard mapping
how is hazard mapping used to protect against a volcanic eruption
- maps out the visual representation of an area where there are hazards that could cause injuries, illness or death
- can be used for places at plate boundaries or near active volcanoes
- allow governments to restrict locals from going over to danger zones containing potential hazards which will reduce the chances of them sustaining injuries or dying
- allow for a greater understanding of safe and dangerous areas in eruptions
- allows exclusion zones to be created to
restrict people from entering danger zones during before or after an event
example of hazard mapping being used to protect against an eruption
In 1997, Soufrière Hills volcano erupted. Through the use of hazard mapping to identify central and exclusion zones, it helped to prevent unnecessary injuries
preparedness strategies used to prepare for a future volcanic eruption
building codes (set of rules that specify the standards for constructed buildings), education, redistribution of losses
why are building codes used to prepare for volcanic eruptions
- effects of ash on buildings depends on the design and construction (flat roofs are more susceptible to damage than steeply pitched ones)
- buildings designed to withstand a heavy load of snow support thicker accumulations of ash
- obstructions on roofs lead to smaller accumulation of ash next to these features
- buildings should be near evacuation routes and away from valleys that could funnel pyroclastic flow and lahars down the slopes
example of how building codes affects damage during an eruption
Building codes in the Philippines mandate that structures in volcanic hazard zones are constructed to withstand volcanic hazards, such as with concrete and steel structures to improve structural integrity. This has helped reduce the impact of volcanic eruptions such as the Mayon volcanic eruption in Legazpi
what education methods help to prepare for a volcanic reaction
- volcanic hazard programs
- emergency preparedness drills
- government educating public
how do volcanic hazard programs prepare for volcanic eruptions
serve to enhance public safety and deliver forecasts, warnings and information about volcanic hazards and release regular updates and notifications to communicate increases or decreases in volcanic activity
how do emergency preparedness drills help to prepare for volcanic eruptions
communities in volcanic-prone areas conduct regular drills to prepare for potential eruptions. this helps residents practice evacuation routes, communication protocols and emergency procedures
how does government education help to prepare for volcanic eruptions
provide hazards education and notification about local hazards and emergency procedures. advise residents about closures, evacuation routes and recommendations for recovery during volcanic activity
why is redistribution of losses used to prepare against effects of eruptions
- make losses tolerable by spreading losses over a wider group of stakeholders and taxpayers
- subsidised insurance for poor farmers and communities living in remote areas of close proximity to an active or dormant volcano
short-term response to a volcanic eruption (hours days and weeks after)
- search and rescue efforts
- helping the injured
- planning of evacuation routes
- provision of emergency shelters
- other necessary aids
example of a country’s short term response to a volcanic eruption
mount bagana eruption in papua new guinea. largest concerns for the region post eruption was water contamination as significant ash and lava discharge contained it. health authorities worked to ensure that the affected population had access to clean and safe drinking water
focus then turned to evacuation efforts of the affected population and efforts were made to address the environmental implications of the eruption (contamination of water, destruction of agriculture)
long-term response to a volcanic eruption (continues for months/years after)
- repair damaged facilities such as transport system
- restoring essential utilities
- rebuilding destroyed properties
- build new infrastructure for properties that have been completely destroyed
- kickstarting local economy
- creating new measures to better prepare for the next disaster
example of a country’s long term response to a volcanic eruption
the eruption of the soufrière hills volcano in montserrat in 1995 destroyed the island’s capital and only airport. in the long term, it relocated its capital and developed resilient infrastructure there to enhance safety, and rebuilt another airport to revive tourism and trade. it also implemented a program to construct more resilient housing that could withstand volcanic hazards. to better prepare for disasters like these, the government established a volcanic monitoring system, emergency management agency and developed a disaster risk reduction plan
