A Level Geography - Hazardous Earth Continued

What was the mitigation (other strategies put in place before the eruption with the aim of reducing the effects) of the Eyjafjallajokull eruption?

- Satellite imagery was used to see the progressions of the volcanic activity, so that countries all over the world could see what was happening and therefore were able to prepare themselves. - Several communication methods were used, messages were sent around the world through phone messages, newspapers, television, radio, etc. These were used to aim to reduce the impacts of the eruption, because people were more prepared and aware that an eruption was happening.

What strategies were used to monitor the Merapi eruption?

- Seismometers - Magnetic measurements - Tilt measurements

Describe the shape and size of strato-volcanoes

- Steep - Conical - Narrow base - Layers of lava and ash

State the features of strato-volcanoes

- Steep sided - Concave shape - Composed of layers of ash from the initial explosion phases of the eruption - Subsequent layers of lava (from the main eruption phase) - Can be over 2000m high - Have a number of underground vents where horizontal (sills) and vertical (dykes)sheets of lava may harden and form intrusive features. - Larger base than a cinder cone

State an example of a lava plateaux

- The Deccan Plateau in central India, which covers more than 500,000 km squared - Colombia Plateau in the northwest USA covers 130,000 km squared

What were the environmental impacts of the Eyjafjallajokull eruption?

- The eruption on 14 April set off a major flood in Iceland, when erupted lava partly melted a glacier prompting authorities to evacuate 700 people. - The mass-grounding of European flights prevented the mission of 2.8 million tonnes of carbon dioxide into the atmosphere.

What are floods?

- Volcanic eruptions beneath an ice field or glacier cause rapid melting. - During an eruption, vast quantities of water accumulate until they find an exit from under the ice. - The resulting torrent of water, which can cause devastating floods.

Describe an example of a super volcano

- Yellowstone, in Wyoming - Has a caldera measuring 75 km in diameter

What is the GNI per capita of Indonesia?

$11,220

What was the financial cost to airlines because of Eyjafjallajokull?

$2 billion over whole time scale $200 million a day

What is the GNI per capita of Iceland?

$52,490

What were some short term responses to the Mount Merapi eruption?

- 210 evacuation centres were set up either as tents, in schools, churches, stadiums or government offices. - 1600 people, either volunteers or military were part of the national aid response. - International aid was offered from organisations such as the Red Cross.

Describe andesitic lava

- 50-65 % silica - Viscous - 800 degrees celsius

What were some immediate responses to the Iceland eruption?

- 700 people evacuated from the southern coastal towns - The government sent rescuers (firemen and ambulance services) by helicopter, because there was glacier meltwater flooding. - Facemasks were distributed to the locals - Flights cancelled

Describe basaltic lava

- < 50% silica - non viscous - 1200 degrees Celsius

Describe rhyolitic lava

- > 65 % silica - Very viscous

State the features of ash-cinder volcanoes

- A small cone (about 300m tall) with a crater at the summit. - Created by airborne fragments of lava cooling quickly and settling around the vent. - Narrow base / small diameter

State the features of caldera volcanoes

- A very large depression (e.g. 1-15 miles in diameter) which may be filled with water. - There may be evidence of new cones forming on the floor of the crater

Why do people choose to live near volcanoes in Indonesia?

- Agriculture opportunities - Can't afford to move away from the area - Very high population density, so not many alternative opportunities to live in - Fertile soil for farming, crops and cattle. - Predictability means that people living by the volcano should know what to do and how to stay safe if there is an eruption. - Sacred volcano, which is worshipped by the locals - Lava and ash provide rich in nutrients solid for Indonesia, and so therefore provide livelihoods to millions.

What were the hazards of the Eyjafjallajokull eruption?

- Ash cloud - Earthquakes - Lava flows - Glacier flooding

Name 2 hazards which arose from Eyjafjallajokull

- Ash column - Glacial flooding

What effect do the gases emitted by volcanoes have?

- Can pose a deadly (and silent) threat to human populations. - When sulphur dioxide combines with atmospheric water, acid rain is produced. This enhances weathering and can damage crops and pollute surface water and soils.

What gases do volcanoes emit?

- Carbon monoxide - Carbon dioxide - Sulphur dioxide

Describe Strombolian eruptions

- Characterised by frequent gas explosions which blast fragments of runny lava into the air to form cones. - Very explosive eruptions with large quantities of pyroclastic rock thrown out. - Eruptions are commonly marked by a white cloud of steam emitted from the crater.

Describe Icelandic lava eruptions

- Characterised by persistent fissure eruption - Large quantities of basaltic lava build up vast horizontal plains - On a large scale, they have formed the Deccan Plateau and the Colombia Plateau

Describe Vesuvian eruptions

- Characterised by very powerful blasts of gas pushing ash clouds high into the sky. - They are more violent than vulcanian eruptions - Lava flows also occur - Ash falls to cover surrounding areas

What are pyroclastic flows?

- Combination of very hot gases, ash and rock fragments travelling at high speed. - They follow the contours of the ground - Destroy everything in their path - The inhalation of such hot and poisonous gas and ash causes almost instant death

What is VEI?

- Combines magnitude and intensity into a single number on a scale from 0 (least explosive) to 8 (most explosive) - Each increase in number represents nearly a ten-fold increase in explosivity.

What is tephra?

- Describes any material ejected from a volcano into the air - Ranges in size from very fine ash to large volcanic bombs (>6 cm across). - Potentially very hazardous - Can bury farmland in layers of ash and destroy crops. - Transport can be disrupted both on the ground and in the air. - Buildings can collapse due to the weight of accumulated ash - People with respiratory problems may have difficulty breathing.

What were some long-term responses to the Iceland eruption?

- Evacuation procedures were carried out - The EU funded a project called 'Future Volc'. This project consists of new and improved sensors (including gas detection meters, geological strain meters, GPS heat sensors and seismometers) - The EU improved the communication of information amongst member countries.

State an example of when a tephra has occurred

- Eyjafjallajokull volcano in April 2010. - Tephra led to the cancellation of 95,000 flights

Describe the shape and size of fissure volcanoes

- Flat - lava plateau - 1-2 km long crack in earth's surface

What were some long term responses to the Mount Merapi eruption?

- Formal evacuation centres were eventually set up, because buildings such as schools and government offices were needed for their official uses. - 2682 people had to be moved to new safer houses permanently. - The government is making money available to farmers to help replace their livestock - The government has set up a special task force to support people that have been affected by the volcano either by family issues, or because they have lost their jobs.

Describe Plinian eruptions

- Gas rushes up through sticky lava and blasts ash and fragments into the sky in a huge explosion - The violent eruptions create immense clouds of gas and volcanic debris several kilometres thick. - Gas clouds and lava can also rush down the slopes. - Part of the volcano may be blasted away during the eruption.

Describe the shape and size of shield volcanoes

- Gentle slopes - Wide - Very large area - Wide base

Describe the explosivity of shield volcanoes

- Hawaiian - Not violent - Effusive

State the features of shield volcanoes

- Huge, gently sloping volcanoes composed of lava - Have wide bases which are several kilometres in diameter with a steeper middle section and then a flatter top (a convex shape) - These can be higher than a composite volcano, e.g. over 4000 metres high - Others have diameters of 3-4 miles

Describe the explosivity of fissure volcanoes

- Icelandic - Not violent - Effusive

What are lava flows?

- Impacts depend on type of lava - Basaltic lava is free-flowing and can run for considerable distances. - Acidic lavas such as rhyolite are thick and pasty so do not flow easily. - Everything in the path of lava will be either burned, bulldozed or buried. - Rarely cause injuries or deaths - Destroy infrastructure, property and crops

Describe Hawaiian eruptions

- Involve more noticeable central activity than the Icelandic type. - Runny, basaltic lava travels down the sides of the volcano in lava flows. - Gases escape easily - Occasional pyroclastic activity occurs

Describe the frequency of eruptions at strato-volcanoes

- Less often / infrequent - Last for a few days to a week

Describe the structure of strato-volcanoes (composite volcanoes)

- Made up of layers of ash and acid lava - Have concave symmetrical profiles - Most contain complex internal networks of lava flows which form minor igneous features such as sills and dykes. - Because acid magma does not flow easily, the vents are often filled with a mass of solidified magma. This plug prevents magma from rising freely from depth. As a result, enormous pressures can build up inside the volcano until eventually it erupts explosively.

What two key factors are considered when assessing volcanic activity?

- Magnitude - Intensity

What mitigation methods were used for the Merapi eruption?

- Monitoring began in 1942 using seismometers in volcano monitoring stations - The monitoring systems have been updated as technology and scientific understanding has progressed. - They had suitable evacuation centres already built and ready for people and livestock, e.g. cows

What was the location of the Mount Merapi eruption in 2010?

- Mount Merapi is located in South east Asia in the country of Indonesia - It is North of Yogyakarta and West of Soko on the island of Java. - It is 1,700 m high and has been erupting since 1500s.

State an example of strato-volcanoes

- Mount Pinatubo, 1991 - Mount Ontake, 2014 - Indonesia has 130 active strato-volcanoes along its archipelago

How often do fissure volcanoes erupt?

- Often - Last for months

How come some of the volcanoes at Hawaii have become extinct?

- Over millions of years, the Pacific plate moves northwest and away from the hot spot. - This causes the volcanoes to lose their source of magma and become extinct.

Describe the explosivity of strato-volcanoes

- Plinian - Violent - Explosive

What were the hazards of the Mt. Merapi eruption?

- Pyroclastic flows - Ash plumes

What were some environmental impacts of the Mt. Merapi eruption?

- Pyroclastic flows destroyed roads and vegetation - Ash, rock and lava deposited on the sides of the volcano were washed down into towns by rainfall creating a lahar. - Sulphur dioxide was blown across Indonesia, as far South as Australia. - Ash from the volcano eventually led to more fertile soils in the area. - Water contaminated with acidic lava and ash - Respiratory problems from contaminated air (ash and acidic fumes)

Give some examples of when pyroclastic flows have occurred

- Roman town of Pompeii was overwhelmed by a pyroclastic flow from Mount Vesuvius in AD 79. - The village of Bronggang was devastated by a pyroclastic flow from the Mount Merapi eruption in 2010.

How many people died as a result of Merapi eruption?

350

How many people were evacuated as a result of Merapi eruption?

350,000

What was the VEI for Merapi eruption?

4

What was the VEI for the Eyjafjallajokull eruption in 2010?

4

What was the VEI of the Eyjafjallajokull eruption?

4

How many people were found dead in the Bronggang village?

55

How many people were evacuated from southern Iceland?

800

A Level Geography - Hazardous Earth Continued

A Level Geography - Hazardous Earth Continued

How was the Eyjafjallajokull eruption monitored?

A combination of GPS, sensors, seismic monitoring and satellite radar interferometry were used to track years of deformations and volcanic activity on and around Eyjafjallajokull.

What is a hot spot?

A hot spot is a fixed area of intense volcanic activity where magma from a rising mantle plume reaches the Earth's surface

How frequent are eruptions in Iceland?

A major eruption happens about once every 5 years

Define what a super volcano is

A volcano that erupts more than 1000 km cubed of material in a single eruption event. Super volcanoes exist as giant calderas.

How many active volcanoes are there in Indonesia?

About 76 have been active in historical times including Krakatoa, Tambora and Merapi.

Describe the characteristics of fissure volcanoes

An elongated crack in the crust allows lava to spill out over a large area

Define resilience

An indication of the rate of recovery from a hazardous even that has put an individual and/or community under stress. It is about how well an individual and society are able to function at an acceptable level when a destabilising force has affected them.

What type of lava is found at strato-volcanoes?

Andesitic lava

How were the Hawaiian Islands formed?

As the Pacific Plate has slowly moved northwest over the Hawaiian hot spot (at an average rate of 10 cm/year), vast amounts of basalt have accumulated on the ocean floor to produce the Hawaiian islands.

State an example of a dome volcano

Puy de Dome & Mt Ventoux, France

Which volcanic hazards from the Merapi eruption impacted the Gendol River?

Pyroclastic flow and lahar

What type of lava is found at acid dome volcanoes?

Rhyolitic lava

Which road in Iceland was affected by the glacial flooding?

Route One

Why are landslides common at volcanoes?

Common, because volcano cones are tall, steep and weakened by magma rise.

What plate boundary do caldera volcanoes form at?

Subduction

What boundary do ash-cinder volcanoes form at?

Subduction boundaries

What boundary do composite / strato-volcanoes form at?

Subduction boundaries

What boundary do dome volcanoes form at?

Subduction boundaries

Which gas was released in sufficient quantities to result in acid rain?

Sulphur dioxide

State an example of a caldera

The 1883 eruption of Krakatoa in Indonesia left a caldera 7 km wide.

What is the most widely used measure of eruption?

The Volcanic Explosivity Index (VEI)

What is magnitude?

The amount of material erupted

What is intensity?

The speed at which material is erupted

What type of boundary do fissure volcanoes form at?

Divergent

State an example of when a strato-volcano has formed on a hot spot

El Teide on Tenerife, in the Canary islands is a strato-volcano which has erupted on several occasions since 1700. The most recent eruption was in 1909.

How do volcanoes impact climate change?

Eruptions emitting very large quantities of ash into the atmosphere can have implications on future climate change.

How frequently does Merapi erupt?

Every 5 years

Give an example of when gases occurred

Eyjafjallajokull, Iceland in 2010

State an example of when floods occurred as a result of volcanic activity

Eyjafjallajokull, Iceland. Several active volcanoes lie under the Vatnajokull ice field.

What type of boundary do shield volcanoes form at?

Hot spots

What happened during the second phase of the Merapi eruption?

Increased earthquake activity and white plumes of smoke were seen. There was a big ash cloud and pyroclastic flow and lahars.

Which two plates are located at the plate boundary that Merapi is located on?

Indo Australian and Eurasian

State an example of a tsunami which was caused by volcanic activity

The tsunamis created by the eruption of Krakatoa in 1883.

What happened during the first phase of the Merapi eruption?

The volcano dome had begun to bulge, some lava was emitted (Andesitic lava)

When do caldera develop?

They develop when an explosive eruption destroys much of the cone and the underlying magma chamber is largely emptied. Without the support of the underground magma, the sides of the volcano collapse to form a caldera.

State an example of when a volcano impacted climate change

Toba, Indonesia led to reductions in global temperatures as ash blocked sunlight from reaching the Earth's surface.

When do volcanoes become hazardous?

When they interact with human communities and activities

What is the name of the nearest major city to the Merapi eruption?

Yogyakarta

Which country's exports fell as a result of Eyjafjallajokull?

Kenya's exports fell, because they were unable to transport flowers and green beans.

State an example of a landslide which occurred as a result of volcanic activity

Lake Nyos in Cameroon

State an example of a shield volcano

Mauna Loa, Hawaii

State an example of when a lava flow has occurred

Mauna Loa, Hawaii in July 2015

State an example of when lahars occurred

Occurred in 1984, following the eruption of Nevado del Ruiz, the Colombian town of Armero was overwhelmed by lahars. The lahars resulted in the deaths of 23,0000.

What month did the Merapi eruption take place?

October 2010

What are calderas?

- Volcanic craters - Usually more than 2 km in diameter

What is the population density of Iceland?

3.25 people per km squared

How many active volcanoes are there in Iceland?

30 - 40 including Hekla and Katla

What were some of the social impacts of the Eyjafjallajokull eruption?

- The people living in the rural areas 'downwind' of the volcano had to wear goggles and facemasks as the ash was so thick. - 500 local cattle farmers and their families had to be evacuated from the area around the volcano. - Many of the roads surrounding the volcano were shut down - The ash contaminated local water supplies. Farmers near the volcano were warned not to let their livestock drink from contaminated streams and water sources, as high concentrations of fluoride from the ash mixed with river water can have deadly effects, particularly in sheep. - 95,000 flights were cancelled - Many people developed respiratory diseases, as a result of inhaling the ash.

What is the tectonic setting of Mt. Merapi?

- The volcano and its eruptions were caused by the Indo-Australian Plate being subducted beneath the Eurasian Plate. - The volcano is located on a destructive boundary at a subduction zone, and is part of the Pacific Ring of Fire. - The Indo-Australian Plate and the Eurasian Plate move towards each other at a rate of 3 centimetres per year. - Mount Merapi is a stratovolcano

What was the tectonic setting of the Eyjafjallajokull eruption?

- The volcano lies on a major fissure of the Mid-Atlantic Ridge, a constructive plate margin. - The North American Plate and the Eurasian Plate. - The plates are moving apart at a rate of 1 to 5 cm per year. - Strato volcano - it is a conical volcano built by many layers of hardened lava, tephra, pumice and volcanic ash. Strato volcanoes are among the most common volcanoes.

Why do people choose to live near volcanoes in Iceland?

- The volcano supplies hot water, which can be used to heat the houses of people living there. - Geothermal energy - Family tradition to live next to volcano. - Tourism there has increased the number of job available there - People living there receive water from the glacier, which can be used to create electricity. - The volcano also provides shelter from the northerly winds - this means that crops can grow well, because they are sheltered from the wind. - Provides a beautiful view - Low cost hot water and heating

What was the location of the Eyjafjallajokull, Iceland, 2010 eruption?

- The volcano was situated in northern Iceland - Iceland is located in the north-west of the UK and to the west of Norway. - Iceland is also near to the Arctic Circle, so therefore it has a cold environment.

What impact do super volcanoes have?

- Their eruptions are very high in magnitude - They release great deep ash layers - They have a huge impact on plant. insect and animal species (palaeobiology)

What were some benefits of the Eyjafjallajokull eruption?

- Tourist attraction - Less carbon dioxide in the atmosphere due to no flights happening. - The addition of the ash to the soil fertilised the soil, and so therefore agriculture benefited. - People were stranded all over the world, so were therefore spending more money whilst being stranded.

What are lahars?

- Type of mud flow - Have the consistency of wet concrete - Snow and ice on a volcanic summit melt during an eruption and flow rapidly down the cone. - Rock fragments large and small, as well as ash and soil, are mixed together. - Lahars can travel at speeds up to about 50 km/h. - Everything in their path is either destroyed or buried under thick layers of debris.

What were some of the economic impacts of the Mt. Merapi eruption?

- Vegetable prices increased because of the damage to crops. - Farmers and other people lost their homes and livelihoods - Government officials reported economic losses from the eruption will surpass $600 million, due to the death of livestock and damage to tourism, manufacturing an agricultural sectors. - Damage and loss in many sectors like social and infrastructure, the impacts of economy, growth, GDP and GNP and unemployment impacts because of the eruption. - Lava flows damaged ski lifts - The eruption brought volcanic tourism, although eruptions can cause tourists to cancel visits. - Mineral mining increased

What were some of the social impacts of the Mt. Merapi eruption?

- Vegetable prices increased, because of the damage to crops - Emergency shelters had to be moved over 15 km away. - Danger area extended to 20 km from the mountain and 278,000 people living in this area had to flee their homes - Planes were grounded - 350 people were killed - 577 people injured - Evacuation centres were crowded leading to poor sanitation, no privacy, and serious disease risk. - People, particularly farmers, lost their homes and livelihoods - Village of Bronggang was devastated. - Villages were under 30cm of ash - 360,000 people were displaced from their homes

How was the nearby Bronggang village impacted by the Merapi eruption?

- Vegetation was destroyed - Tarmac of the road was too hot to walk on, as a result of the pyroclastic flow. - Roof tiles were removed from houses - Green areas and roads were covered in ash - Electric poles and telecommunications were damaged - Rescuers wore facemasks because of the ash - Lots of people got burned walking along ground barefooted. - There was total devastation caused by lava and pyroclastic flows

Describe the frequency of eruptions at acid dome volcanoes

- Very infrequent - Short duration

Describe the frequency of eruptions at shield volcanoes

- Very often - Last for months

Describe the shape and size of acid dome volcanoes

- Very steep - Convex slopes composed of solely lava

State the features of dome volcanoes

- Very steep sided - Convex shaped cones formed from just lava - A solid lava spine may emerge / be present extending upwards from the central vent. These have a narrow base (up to 1 kilometre in diameter) and 500 - 1000 metres high.

Describe the explosivity of acid dome volcanoes

- Violent - Very explosive

What are tsunamis?

- Violent eruption of some island volcanoes can cause massive displacement of ocean water and tsunami waves capable of travelling at speeds of up to 600 km/h. - In deep water they have a height that is usually less than 1 m and a very long wavelength of up to 200 km. - Approaching the shore, tsunami waves increase rapidly in height and when they break, transfer vast amounts of energy and water along the shore and inland.

Describe Vulcanian eruptions

- Violent gas explosions blast out plugs of sticky or cooled lava - Occur when there is very viscous lava which solidifies rapidly after an explosion. - Often the eruption clears a blocked vent and spews large quantities of volcanic ash into the atmosphere.

What were some economic impacts of the Eyjafjallajokull eruption?

-Airlines lost a combined £130 million per day in lost revenues, according to International Air Transport (IATA). - Europe's biggest tourism businesses lost between £5 million and £6 million per day. As passengers looked for other ways to travel than flying, many different transport companies were able to benefit. - There was a huge increase in passenger numbers on Eurostar. It saw an increase of 50,000 extra passengers travelling on their trains. - Exporters and perishable goods from the Caribbean and Africa were badly affected. - Kenyan farmers reportedly resorted to dumping stocks of fresh food and flowers, which would otherwise have been sold to Europe. Kenya's economy lost £2.8 billion because of flights to Europe being cancelled.

How many people were killed by Eyjafjallajokull?

0

What is the population of Iceland?

0.3 million

How does a lava plateaux form?

1) Basic magma erupts from multiple fissures 2) Vast areas can be covered by free-flowing lava. These events are known as flood basalts. 3) When first formed these plateaux have a uniform slope of around 1 degrees. 4) However millions of years of denudation have created more varied relief. - No large-scale flood basalt events have taken place in the past 50 million years.

What is the population density (people per km squared) of Indonesia?

137.90

What is the total population of Indonesia?

264 million

State an example of a fissure volcano

Badabunga, Iceland in 2014

What type of lava is found at fissure volcanoes?

Basaltic lava

What type of lava is found at shield volcanoes?

Basaltic lava

What were the political impacts of the Eyjafjallajokull eruption?

Political meetings between neighbouring countries and global organisations were delayed, because it was unsafe to fly.

What were some political impacts of the Mt. Merapi eruption?

Political meetings were delayed