Geography - earthquakes and volcanoes - Y11
Mount Nyiragongo, Congo -what are the responses?
. Aid agencies gave bedding, equipment to provide clean water for drinking and sanitation, blankets, tents, food and cooking utensils to refugees. . Un supplied 260 tonnes of food, enough for 700,000 people for a week.
Mount Merapi, 2010 - Background infomation
. Active volcano on island of Java, Indonesia . Most Active volcano on island, it has been erupting since 1500's. . Is seen pouring out smoke 300 days a year . 3km in height . Erupting 3 times from the 25-26 of october . Erupted one more time 4 days later . In the pacific ring of fire . Occurred at a destructive plate boundary . 350 died . 280,000 population . Pyroclastic flow is unpredictable and you can not escape.
Give examples of natural hazards
. Volcanoes - geological . Earthquakes - geological . Flooding - hydrological . Tornado - atmospheric
Define a natural hazard
A natural hazard is a natural event that causes damage to property and/or disruption to normal life and may cause loss of life.
What is monitoring volcanoes?
Because volcanoes go give warning signs (change in shape, temperature, etc) it is very important to monitor them carefully so that you can give nearby residents warning.
Earthquake in L' Aquila, Italy - causes of the earthquake
Caused by eurasian plate and African plate colliding (destructive plate boundary)
What are primary hazards?
Caused by the actual event itself. Eg for an earthquake ground shakng and surface faulting.
What is cooling lava?
Cooling lava- in Iceland in the past they have tried spraying seawater onto lava. The idea was to make the lava go cold and turn into rock before it destroyed nearby settlements.
What is a diversion channels?
on some volcanoes it has been attempted to make diversion channels to direct the lava away from settlements. This is very expensive and hard because you can not predict which direction the lava will flow.
Nepal case study -primary impacts
. A total of 8, 841 dead . 16,800 injured . 1 million made homeless . 200 people trapped in buildings . Destruction of 26 hospitals and 50percent of schools . Reduced supply of water, food and electricity. . 352 aftershock.
What are hazard mapping?
It is very important to map the most dangerous areas near a volcano eg areas with the most unstable grounds or areas where lava flows are likely to travel. Once you have mapped dangerous areas you can then stop settlements being built on them.
What are evacuation routes?
It is very important to plan evacuation routes for individual houses and whole settlements. It is also important to regularly practise these evacuation routes.
What does the Richter scale measure?
It measures the size and magnitude of an earthquake
Earthquake in L' Aquila, Italy -secondary effects
. Aftershocks triggered landslides and rockfalls . A landslide and mudflow was caused by a burst main water supply pipeline near the town of Paganio . Number of students at L' Aquila University has delivered . Lack of houses means rent was up . Still some 'red zones'
Nepal case study -secondary effects
. 19 died after the earthquake triggered an avalanche on Mt Everest. (Several tourists) . Tourism was 8.9 percent of zneoals GDP. ( provided 11 million jobs) . Earthquake happened before rice was planted and 2/3 of the population depended on farming . Food shortages . Income loss
Nepal case study - long term responses
. 23 areas needed rebuilding such as houses, schools, roads, monuments and agriculture. . 274 million dollars of aid had been committed to the recovery efforts. . Mt Everest was opened for tourists again
What are Lahars?
. 2nd most hazardous . Travel down the volcano as fast moving mud . Normally occur on snow covered volcanoes. Hot ash and gas melt the snow and then mix
What are volcanic bombs?
. 2nd to least hazardous . Semi-molten pieces of rock . As long as humans are a safe distance they don't really cause any problems
Earthquake in L' Aquila, Italy - Primary effects
. 308 people were killes . 1,500 were injured . 67,000 were made homeless . Struck at 3.32am so most people are asleep in buildings . 10,000-15,000 buildings collapsed included: -churches -national museum -san Salvatore hospital -several buildings in L' Aquila university
What is poisonous gas?
. 3rd most hazardous . Can kill humans or animals . Can contribute to the greenhouse effect . Such as carbon monoxide and sulphur dioxide
Mount Nyiragongo, Congo -social impacts
. 45 killed in the first 24 hours . Lake Kivu polluted by sulphurous gases - drinking water . Lava flows created fires
What are ash clouds?
. 4th most Hazardous . Weight of ash clouds can collapse the buildings . Not as fast moving . Can be very disruptive . An reduce sunlight
Primary effects of the boxing day tsunami
. 650,000 people were seriously injured . 141,000 homes destroyed . 1.7 million were made homeless. . 230,000 were killed . 1000 of those killed were German and Swedish tourists. . 1/3 of those killed were children . 8000 tourists from America, Australia and Europe were killed.
What is a shield volcano?
. Basic lava, which is non-acidic and very runny . gentle sides as the lava flows for a longer distances before it solidifies . No layers , as the volcano just consists of lava . Less violent eruptions . Shorter periods between eruptions . Mainly formed at constructive plate boundaries.
How to prepare for earthquakes
. Better forecasting and warnings . Building design, building location and emergency procedures . Safe houses are built . Evacuation drills . Emergency proof buildings . Deeper foundations in buildings . Avoid building on soft soil . Use straw, adobe or old tyres . Reinforce concrete walls of steel . Ensure strict building regulations . Emergency services are trained and prepared . Road design to avoid elevated motorways
How do scientists predict when a volcano is about to erupt?
. Change in shape or size of volcano . Change in the temp of a volcano . Change in the amount of type of gases being released . Earthquake activity . Change in plant and animal life . Change in local hydrology eg temp and chemical composition of nearby rivers
Impacts of earthquakes on richer countries
. Country has enough money to pay for supplies and help with rebuilding programmes . Evacuation is tested regularly . Airfields to bring in rescuers and emergency supplies are often located many miles away . Hospitals are well prepared for victims . Computers used to manage relief . Counselling for emotionally distressed children . Emergency rescue teams with heat-seeking equipment reach disaster areas within minutes . Emergency health kits with a shelf life of 5 years . Huge fires quickly brought under control by well-trained fire crews . People are evacuated quickly and secondary damage is limited . Instant communication about damage . Psychological and emotional damage to those involved . Helicopters are used to transport rescue teams and evacuate the injured . Most electrical and gas supplies reconnected within hours.
Mount Merapi, 2010 - secondary effects
. Crops destroyed . Heavy rain washed Ash, lava and rocks down slopes so citizens had to move away . 781 million dollars spent . Sulphur dioxide travelled as far as Australia
Preparedness and vulnerability in LEDCs
. Don't follow building codes . Many ledcs suffer from rapid urbanisation and uncontrolled growth of settlements on dangerous marginal lands. . Medical care is poorer . Rely on emergency Aid after disasters or at the time of natural disasters, but emergency aid always takes several days to mobilise which will usually cost lives. . Transport and communications will be poorer in LEDCS. Much of the population will not have phones or televisions so will not be warned about natural disasters. . Will not be adequate supplies of blankets, tents, food and clean water. . Services like electricity and water will take longer to prepare, leading to disease and exposure . A lot of the population will not know how to respond to the disaster. . Less money will be spent on monitoring potential hazards . Evacuation routes may not exist and there may be a shortage of shelters. . Poor LEDC cities often have a high population density. This causes more people to be effected by the primary and secondary hazard.
Mount Merapi, 2010 -responses
. Erupting regularly since 1548 . 2010 eruption was expected . 19,000 people evacuated . Early warning systems . Used Tiltmetres and seismetres . Disaster risk reduction handed out masks . 1600 volunteers and Military forces helped . 210 evacuation centres set up in schools, churches, stadiums and gov offices . 2682 people re-homed . Task force to help comfort people . Gov made money available for farmers who lost everything
Mount Nyiragongo, Congo -environmental impacts
. Goma split in half . 90km/h lava flow . Opened a fissure 13km long x2km deep . 14 villages destroyed
What happens at a collision plate boundary?
. Happens when 2 continental plates collide . They have the same density so neither plate can be sub ducted under the other. . When they move together, pressure builds, eventually causing the plates to buckle and fold up, creating fold mountains (eg the Himalayas) . You get big mountains at collision boundaries because there is a massive build up of friction and pressure. . Earthquakes are the release of energy called seismic waves. Because no plate is being destroyed, magma is not being created, so you do not get volcanoes.
Why are more people affected by natural hazards now then they were in the past
. Higher population . Increased number of people living in poverty who lack resources to cope with natural hazards . Changes in the natural environment, causing increased frequency and intensity of storms, floods and droughts . Increased levels of urbanisation, including more sanity town, which are often located in hazardous environment . Changing land Use in rural areas, which results in flash floods, soil erosion and landslides.
Earthquake in L' Aquila, Italy - immediate response
. Hotels provided shelter for 10,000 people . 40,000 tents were given out . Train carriages used as shelters . 36 ambulances and a temporary hospital . Red cross raised £171.000 in support
What is a composite volcano?
. It has Steep sides as the lava doesn't flow very far before it solidifies. . Alternate layers of Ash and Lava. For this reason, they're also known as stratovolcanoes. Strato means layers . Violent eruptions . Longer periods between eruptions . Mainly formed at destructive plate boundaries
Mount Nyiragongo, congo -impacts
. Lava covered parts of the Goma . Around 147 people died from suffocatioj by CO2 or buildings collapsed due to the lava and earthquakes. . 120,000 people homeless . 400,000 people evactuated
Mount Nyiragongo, Congo - economic impacts
. Lava crossed Goma Airport meaning it was unusable - so people could not come and help very easily and citizens could not leave. . Immediate loss of business as they burn down.
What is lava flow?
. Least hazardous . Lava flows only travel a couple of km per hour so it is possible to move out of the way . Can bury and incinerate any land or properties.
What do earthquake buildings have?
. Light walls and gables - are subject to smaller forces so are less likely to fall. . In Pakistan they are being built of straw . Light roofs - so that they Are less destructive when they fall, more resistent . Small windows - creating fewer weak spots in walls . Reinforced walls - prevents collapse -made of metal, bamboo or plastic . Confined masonry - in a quake the structure moves as a unit . Shock absorbers - tyres filled with stones or sand are fastened between floor and fountain and serve as cheap shock absorbers for many buildings
Impact of earthquakes on poorer countries
. Limited food supply . Homelessness . Difficult to warn them of likely damage - no Tv signals . Roads and railways are not of good standard - difficult to reach victims . Poorly built buildings . Unemployment is caused . The gov is slow to help people . Psychological and emotional damage to those involved . Faulty emergency supplies and telephone lines . Collapsed bridges and blocked roads . Long term economic damage, as the gov has to spend billions on rebuilding. . Unhealthy living conditions and lack of food cause further deaths through disease and starvation.
Secondary effects of the boxing day tsunami
. Loss of foreign income from tourism was significant in Thailand especially . Incomes were lost due loss of fishing boats and destruction of work places . Diseases spread due to lack of sanitation . Coral reef damaged . Mango, rice and banana plantations in sri Lanka destroyed . Psychological impacts on people
Preparedness and vulnerability in MEDCS
. Many MEDCs do hazard mapping and zonal planning. They will assess the risk for different areas of the country eg is it likely to flood or be in lava flow. They will then only allow low value and low risk land uses in hazardous areas. . Strict building codes to protect against earthquake damage . Entire population will be educated about hazards . Emergency and rescue services . Scientists will make predictions about when a disaster will happen . Transport and communications are usually much better . They can afford to spend more money on training and preparedness. . There will be stockpiles of tents, blankets, food and water for anyone who has lost their home and possessions.
Hoe to predict an earthqauake
. Measuring crystal movement- small scale movement of plates . Recording changes in electrical conductivity . Noting strange and unusual animal behaviour, for example among fish (eg carp) . Checking historical evidence to see if there are possible trends in when earthquakes happen
Name examples of a composite volcano
. Mount St helens . Mount fuji . Mount rainer . Mount vesuvius
Name examples of a Shield volcano
. Mount loa . Mount klauea Both on the Hawaiian islands
Why do people live near volcanoes?
. Nice to look at . Minerals like sulphur . Geothermal potential - cheap and clean energy eg iceland and El Salvador . Tourism . Popular tourist destinations . Hot springs near volcanoes - tourists and locals can enjoy . Land around volcanoes is very fertile . Poverty - people can not afford to live anywhere else . Volcano has not erupted for a long time . Confident they will be given warning to evacuate . Family home - don't want to leave as they have always lived there . Shortage of space and high population density
What are 2 views of vulnerability?
. One view is that people choose to live in hazardous environments because they understand the environments. in this situation people choose to live in an area because they feel the benefits outweigh the risks. . Another view is that they have very little choice over where they live, as they are too poor to move.
How can we predict volcanoes?
. Seismometer, to record swarms of tiny earthquakes that occur as the magma rises . Chemical sensors, to measure increased sulfur levels . Lasers, to detect the physical swelling of the volcano . Measurement of small scale uplift or subsidence, changes in rocks stress and changes in radon gas concentration . Ultrasound, to monitor low-frequency waves in the magma, resulting from the surge of gas and molten rock, as happened with Mt pinatubo, El chichon and mt st helens.
What are the 2 main types of volcano called?
. Strato- volcanoes (composite) . Shield volcanoes They vary in height, shape, size, formation, characteristics but have many similar features.
What happens at a constructive plate boundary?
. The plates diverge/move apart . Although not as violent as those on destructive plate boundaries volcanoes and earthquakes do occur on constructive plate boundaries, which causes mid-ocean ridges to form. At a constructive plate boundary 2 plates move away from each other due to convection currents in the mantle caused by geothermal energy in the core. Magma rises from the mantle to fill the gap between the two plates. Volcanoes can form at constructive plate boundaries as well. This is due to the rising magma. They form along the edges of the plate boundaries . These volcanoes are called shield volcanoes. Magma can form underwater volcanoes and the lava creates a mid-ocean ridge. Oceanic plates are forced apart. Molten magma rises in between and cools down to form solid magma. This forms part of the oceanic plate, which can fracture as it mores causing earthquakes (shallow, small and non violent.
Why do people live in earthquake prone areas?
. They rely on advanced technology . They have always lived there . They have got friends and family there . They cannot afford to leave . Part and place of where they live . Might have never seen an earthquake happen in there live so they do not understand the consequences
Earthquake in L' Aquila, Italy - long term responses
. Torch lit procession . Residents did not have to pay taxes during 2010 . Students were given free public transport and were exempt from university fees for 3 years . homes took several years to rebuild and historic centre are expected to take 15 years
Why live in a danger zone?
. Tourism - climb Mt Vesuvius, visit Pompeii, visitors need places to stay such as hotels. This creates jobs. . Do not erupt very often - insurance policies, last earthquake in Tokyo was 1923. . Minerals - gold, diamond, mining jobs, exports for world markets . Use geothermal energy- iceland, cheap . Early warning systems - government invest in earthquake proof buildings . Economic advantages - volcanic soil good for grape growth, fertile soil, coffee can be grown in columbia and rice in Indonesia. . 500 million people live near danger zones . Communities develop - 2,000,000 live near Mt versuvious, Can not afford to leave, people have got jobs, friends and family there. Livelihood there.
Nepal case study - immediate response
. Uks DEC raised 126 million dollars by September 2015 to provide emergency aid. . The red cross provided 225,000 people with tents . 315,000 people were cut off by road and 75,000 were additionally unreachable by Air.
Mount Merapi, 2010 - primary effects
. Volcanic bombs flung as far as 11km . 800c gases recorded . Village 15km away covered in ash . 350 died - mainly due to respiratory problems and burns . 280,000 made homeless . Airport and roads closed
The extent of the earthquake damage varies depending on....
. building regulations - deepness of foundations, materials . Building density - flats collapsed . Time of year - tourists . Location of epicentre - close to capital - Halti 2010 . Population density . Magnitude . How developed a country is - higher wealth = higher quality buildings . Location - nepal 2015- avalanches (Himalayas) secondary impacts - proximity to coasts - boxing day 2004- 12 countries affected in indian ocean. . Emergency services . Building design . What plate boundary . Depth of focus . How prepared a country is . Time of day . Population density
State 3 differences between continental and ocean crust
1) oceanic crust consists of basalt rock and continental crust consists of granite rock. 2) oceanic crust sinks lower than the continental crust 3) oceanic crust is on average 5km thick compared to continental crust which is from 20-50km.
What is a chamber?
A chamber refers to the reservoir of magma located deep inside the volcano
What is a Constructive plate boundary
A constructive plate boundary, sometimes called a divergent plate margin, occurs when plates move apart. Volcanoes are formed as magma wells up to fill the gap, and eventually new crust is formed.
What is a continental plate?
A continental plate is a geological plate in which covers most of the crust
What is a crater?
A crater is the depression at the top of a volcano following a volcanic eruption. It may contain a lake.
What is a caldera?
A large volcanic crater, especially one formed by a major eruption leading to the collapse of the mouth of the volcano.
What are plate tectonics?
A theory explaining the structure of the earths crust and many associated phenomena as resulting from the interaction of rigid lithosphere plates which move slowly over the underlying mantle.
What is a vent?
A vent is the channel that allows magma within the volcano to reach the surface in a volcanic eruption.
Short term responses to the tsunami by non-governmental organisation
Action aid raised £13 million and immediately sent food aid
What is the oceanic plate?
An oceanic plate is a tectonic plate at the bottom of the oceans
What is an extinct volcano?
Are not expected to erupt again. Kilimanjaro in Kenya is an excellent example of an extinct volcano.
What is an active volcano?
Are those that have erupted in recent time such as Mt Pinatubo in 1991 and Montserrat in 1997
What is a Dormant volcano?
Are volcanoes that have not erupted for many centuries, but may erupt again such as Mt rainer in the usa
Why do scientists look at volcanic history?
As part of monitoring the volcano you can look at its history and previous flows. You can then try and calculate frequencies and areas that are likely to be effected.
Impacts of a super volcano
Ash falling thousands of miles, changes the global climate for tears to decades, causing much colder weather, damaging buildings and shutting down power plants.
Long term responses to the tsunami by the gov
Country govs helped to rebuild whole community towns, including in Indonesia in Aceh province. An early warning system for Tsunamis has now been put in place in the Indian ocean, through co-operation from many govs. The uk gov disasters and emergency committee established an earthquake/ Tsunami disaster appeal fund stood at £32 million, up £7 million in one night from the 31st of December. At one point the DEC was receiving around £15000 a minute in donations via the phone and web. Countries send AID teams immediately. MEDCs sent dog teams, forensic experts and equipment to help identify bodies and to help clean up.
Why do countries find it hard to recover after a disaster?
Death - many workers have been killed so less money is being generated. Injury- more money will have to be used to treat injuries Damaged transport links - roads, ports and airports may be damaged, so people will find it hard to travel to work and the country will find it harder to import and export. Damaged communications - phone lines and internet links are often damaged during disasters and communications remaining are often overloaded. Without communications many businesses find it hard to operate and governments will find it hard to coordinate recovery efforts. Loss of income - because businesses will have been damaged and less workers, a fall in income so will have less money to spend on recovery. Psychological impacts - citizens will be fearful of more disasters or to return to work. Others will be grieving so unable to work fully. Shortage of food and water - lead to illnesses and malnutrition. If you have ill or weak people recovery will be slower . Electricity shortages -most businesses need electricity to work. Recovery will be slower . Damaged equipment - equipment will need replacing, costly and recovery will be slower . Damaged buildings - important gov buildings, hospitals and power stations can be damaged during disasters. If you are lacking power then recovery will be made harder.
Short term effects of disaster
Death- lead to grieving families, but bodies need to be cleared before disease starts to spread. Injury- these people need to be treated, this uses percious resources and costs money Panic and fear- people scared pf a repeat disaster, aftershocks Secondary hazards - like fire might damage large areas or even kill more people after a disaster. There may even be further primary hazards like aftershocks. Infrastructure damage - electricity, water, transport and communications links will all be damaged. Could lead to food shortages.
Volcano Preparedness and reaction
Diversion channels Cooling lava Sweeping roofs Making evacuation routes Exclusion areas Hazard Mapping Monitoring volcanoes Looking at volcanic history (previous eruptions and flows) Volcanic plug
What is sweeping roofs?
During ash showers it is very important to regular sweep off roofs. If this is not done the ash will get so heavy that it will eventually cause the building to collapse.
What is a Destructive plate boundary
Is sometimes called a convergent or tensional plate margin. This occurs when oceanic plate and a continental plate move together. The oceanic plate is forced under the lighter continental plate.
What is friction?
Rubs agains
What is tension?
Energy that builds up
Long term effects of disaster
Homelessness- could take months or years to rebuild Unemployment - industries and buildings get destroyed however some jobs will be created in the rebuilding efforts. Dependency - countries who have suffered a disaster will normally see there income decline. This makes them reliant on international aid and foreign countries. Long term injuries - victims will need long term care Disease- diseases normally start because of dirty and temporary living conditions and dirty water Post traumatic stress disorder - people who have experienced disasters or lost loved ones will experience psychological problems long term. Rebuilding costs - eventually everything will have to be rebuilt. This is expensive and the money will have to be diverted from other areas eg education. Countries will have to raise taxes. Infrastructure damage - a lot of infrastructure will be damaged long-term making recovery very hard.
What are Exclusion areas?
If an eruption is happening or likely to happen it is important to create exclusion zones. This means evacuating everyone that could be effected by the eruption. Because pyroclastic flows can travel up to 30km, these exclusion zones can be very big
Long term responses to the tsunami by non governmental oragnisations
In the long run action aid offered psychological counselling, paid for housing, paid for boats with motors for fishing communities, rebuilt schools and community centres, in an attempt to rebuild areas.
What is a mantle?
Is a semi-molten and about 2900km thick
What is the outer core?
Is semi-molten. It is a fluid layer about 2,400 km thick. It is composed mostly of iron and nickel.
Examples of super volcanoes
Lake Toba, the yellowstone caldera, the long valley caldera, vallies caldera, tallpo caldera, Aira Calder
How might managing earthquakes differ between LEDCS and MEDCS?
MEDCS HAVE - - earthquake proof buildings (more money to invest in better buildings) - better training for emergency services - better equipment used to predict (better technologies) - evacuation drills for quicker evacuation - most electrical and gas supplies reconnected within hours
Long term responses to the tsunami by individuals
Many people have re-established buildings and business in the affected regions, but many people permanently migrated from the area. See Aceh province 5 years after the disaster.
Name an example of a constructive plate boundary
Mid-Atlantic Ridge (MAR) (can be observed on land in Iceland). The north American plate moving away from the eurasian plate.
Mount Nyiragongo, congo -cause
Months of increased earthquakes and steam/gas eruptions. This resulted in 13km fissure opening on the south flank of the volcano. Warning had been given and 400,000 people were evacuated from the city.
What is Pyroclastic flow?
Most hazardious . Giant clouds of ash and gas (500km/hr) . 30km . Can be over 700 degrees centigrade
Short term responses to the tsunami by individuals
Most individuals ran for their lives. They climbed buildings, hills and trees. Some people Froze, they walked to the seaside to watch the wave approach snd could not escape once they realised what was going on.
Mount Nyiragongo, congo - plate boundaries
Mount Nyiragongo is part of the African Rift Valley where the African plate is splitting into two plates called the Somali plate and the Nubian plate. The lava lake at Mount Nyiragongo has been continually erupting since 2010. It happened because Tectonic movement in the Kivu rift resulted in a fracture where the lava fkowed from fissures. The plate boundary is a constructive plate boundary..
Mount Nyiragongo, congo -general facts
Mount Nyriagongo is located inside Virungo National park, in the Democratic republic of the congo about 12 miles north of the town of Goma and lake kiva. The highest point of the volcano is 3,470m. It last erupted in 2002. The lave lake has an estimated depth of 600m. Since 1882 Mt Nyragongo has erupted 34 times. In the whole world there are 4 permanent lava lakes but mount nyiragongo is the largest and the most active.
What is a Convection currents?
Movements within the earths mantle caused by the heat of the core.
Nepal case study - causes of the earthquake
Nepal sits on the boundary of the 2 massive plates that collide to form the Himalayas. Collision plate boundary. Indian tectonic plate pushing under Eurasian plate.
What are the differences between continental and oceanic crust?
Oceanic. Continental Age. 200 million years. 4 billion years old Thickness. 6km thick. 35km to 40km thick Density. More dense. Less dense Rock type. Basalt. Gravitic, sedimentary and metamorphic Where found. Under the ocean. Under the Himalayers
Earthquake in L' Aquila, Italy -background information
On 6th April 2009 an earthquake measuring 6.3 on the richter scale. The earthquakes epicentre was seven Kilometers northwest of L' Aquila
Nepal case study -back ground infomation
On the 28th april 2015 an earthquake of a 7.8 magnitude hit Gorkha, Nepal. The Earthquakes epicentre was in Baroark, 80 km northwest of the capital.
What happens at a conservative plate boundary?
Plates are sliding past each other at similar angles but at different speeds or different angles eg. Loma prieta earthquake in 1989. Friction means they get caught on each other, the pressure builds and then is suddenly released as they jolt into a new position. This causes energy to be released as seismic waves as an earthquake. No volcanoes at this margin. A fault line is a fracture in the earths crust.
What is a hazard risk
Possibility of loss of life or damage
What is a conservative plate boundary?
Sometimes called a transform plate margin, occurs where plates slide past each other in opposite directions, or in the same direction but different speeds. Friction is eventually overcome and the plates slip past in a sudden movement, causing an earthquake.
Definition of a supervolcano
Super-volcanoes are usually large volcanoes having the potential to produce and eruption with major effects on global climate and ecosystems.
Name an example of a fold mountain
The alps
What is a plate margin (plate boundary) ?
The boundary of one of the plates that form the upper layer and together cover the surface of the earth
What is a crust?
The crust of the earth is composed of igneous, metamorphic and sedimentary rocks. It is divided into 2 main types ocean crust. The depth of the crust varies between 10km and 70km.
What are tectonic plates?
The earths crust and upper part of the mantle are broken into large pieces called tectonic plates. These are constantly moving out a few centimetres each year.
Short term responses to the tsunami by the gov
The gov of the affected countries reached reasonably quickly but were reliant in many cases on outside AID due to the magnitude of the disaster and the lower level of economic development of the places affected. India sent naval ships to affected areas, whilst Thailand, Indonesia responded but slowly, given the extent of the disaster. The first tasks of the gov and humanitarians aid agencies were to insure access to food and clean water, and medical care for the injured. The world health organisation warmed that the number of deaths from preventable diseases such as cholera and typhoid could control the death from the disaster itself.
What is the inner core?
The inner core is a dense ball of solid metal. It is 5x denser than surface rocks.mit has a radius of about 1,220 kilometres.
What is the epicentre?
The point above the focus on the earths surface
What is the focus
The point within the earth where the seismic waves of the earthquake start
Where are volcanoes found?
The volcanoes of active volcanoes are uneven. There are a lot on the indo-Australian plate boundary. There are 14 on the North American plate boundary . They are mostly along plate boundaries. However, there are some which are not near to plate boundaries such as there are 3 together in the African plate boundary (these are called anomalies). There are around 1300 active volcanoes in the world many of them under the ocean.
What are secondary hazards?
These happen due to an after event of a hazard eg a land slide, a rock fall, a tsunami, a mud flow, debie flows, ground failure, soil lignefaction , fires, contaminated water (which could spread diseases eg cholera), hunger and hypothermia. This occurs due to the occurrence of a primary hazards.
Describe distribution of earthquakes and volcanoes
Volcanoes and earthquakes are distributed unevenly around the globe. Most volcanoes and earthquakes are located on the edges of tectonic plates. However, there are some anomaly's and isolated volcanoes and earthquakes mainly in the African plate. There are also clusters of earthquakes on the edge of the pacific plate. In west of Africa there are isolated volcanoes and earthquakes. Linear clusters are found in the western part of the pacific ocean.
What are seismic waves?
Waves of energy in an earthquake
What is a collision plate boundary?
When 2 continental plates collide. Neither plate is forced under the other, and so both are forced up and form fold mountains.
When does a hazard become a disaster
When it affects people and there properties
What is a volcanic plug?
You can attempt to make an artificially volcanic plug by dropping boulders or concreter into a crater or vent. This is dangerous and unlikely to be successful. In fact it might build up the pressure in a volcano and cause a more violent eruptions.
What is a tsunami?
a series of water waves that travel away from a fault in all directions at high speed
What is a fold mountain?
large mountain ranges where rock layers have been crumpled as they have been forced together
