4.a There are a range of impacts people experience as a result of volcanic eruptions.

Question 1

Volcanic description is based on what?

(Active, dormant, and extinct volcanoes)

Answer 1

Volcanoes will be described as active, dormant, or extinct - based upon their eruption history,

Question 2

Why is it difficult to define volcanoes?

(Active, dormant, and extinct volcanoes)

Answer 2

Many volcanoes that have erupted in the past show no signs of activity today.

They may appear dormant on a human timeline, however, on a geological timeline they are relatively active.

Question 3

What is a limitation of trying to define volcanoes?

(Active, dormant, and extinct volcanoes)

Answer 3

Time spent debating definitions means that effective preparation is reduced, in actually combating these eruptions.

Question 4

What do many scientists consider to be the definition for an active volcano? What is the challenge with this approach?

(Active volcanoes)

Answer 4

Many scientists consider a volcano to be active if it has erupted in historic times.

The challenge with this approach is that different regions have different records, e.g. the Mediterranean has records extending 3000 years whilst North America only has 300 years’ worth of records.

Question 5

What is the least popular definition for active volcanoes?

(Active volcanoes)

Answer 5

One that is currently erupting or there is evidence of unusual earthquake patterns or gas emission.

Question 6

What is the most popular definition for active volcanoes?

(Active volcanoes)

Answer 6

Smithsonian Institutes Global Volcanism Programme combined a list of 1500 active volcanoes.

It states that an active volcano is one that has erupted since the last glacial period or within the past 10,000 years.

Question 7

What is the most popular definition for dormant volcanoes?

(Dormant volcanoes)

Answer 7

Smithsonian Institutes Global Volcanism Programme.

One that has not erupted during the past 10,000 years but it is expected to erupt sometime in the future.

Question 8

What is a challenge with the SIGVP’s definition for dormant volcanoes?

(Dormant volcanoes)

Answer 8

Mount St Helens was considered dormant before its eruption in 1980, while the Yellowstone caldera has not erupted for 70,000 years but is certainly not considered extinct.

Question 9

What is the definition for an extinct volcano?

(Extinct volcanoes)

Answer 9

A volcano that is not expected to erupt again.

Question 10

Based on the definition of the Global Volcanism Programme, how many active volcanoes does Japan have? What is also included in the list?

(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 10

110 active volcanoes.

Included within this list are several submarine volcanoes, just off shore from the Japanese mainland.

Question 11

What percentage of Japan’s land mass is mountainous? Why is this?

(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 11

70% of Japan’s land mass is mountainous, formed by volcanic activity over millions of years.

Question 12

How does culture play a role in Japan’s volcanoes? Give an example.

(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 12

Much of Japan’s folklore is associated with volcanoes.

E.g. Mount Fuji, is an important part of Japanese tradition, myth, and legend.

Question 13

Japan is located in one of the most tectonically active zones in the world. Why?

(Tectonic Setting)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 13

It is where 4 tectonic plates meet and widespread subduction gives rise to intense volcanic activity.

Question 14

Historical evidence records nearly how many volcanic eruptions in Japan over the last 2000 years?

(Tectonic Setting)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 14

Historical evidence records nearly 1200 volcanic eruptions in Japan in the past 2000 years.

Question 15

The average frequency of eruptions of different scales in Japan suggests what?

(Tectonic Setting)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 15

Suggests that the more explosive the eruption, the less variable its frequency.

Smaller eruptions are more variable.

Question 16

How tall is Mount Ontake? What is the summit covered in?

(Mount Ontake)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 16

Rises to just over 3000 m and its summit is often snow-covered.

Question 17

Mount Ontake was thought to have been dormant for many centuries, until when?

(Mount Ontake)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 17

Until a sequence of eruptions between October 1979 and April 1980 - with further eruptions (some of them small phreatic eruptions) following in 1991 and 2007.

Question 18

Mount Ontake is popular for who?

(Mount Ontake)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 18

Climbers and trekkers and was a noted tourist destination, with various facilities including a lodge close to the summit.

It was also a place of spiritual pilgrimage for many Japanese people.

Question 19

When did Mount Ontake erupt?

(Mount Ontake Eruption)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 19

Erupted on 27 September 2014, just before midday, without warning.

Question 20

Was the Volcano being observed when it erupted?

(Mount Ontake Eruption)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 20

No, it was not under any alerts or warnings, although some increase in earthquake activity had been observed.

Question 21

Outline impacts of the eruption.

(Mount Ontake Eruption)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 21

Killed 63 people and large areas surrounding the volcano were affected by ash fall, pyroclastic flows, volcanic bombs and lahars.

Most casualties were climbers and hikers on the slopes of the volcano.

More than 200 survivors made it down the mountain and search and rescue teams were deployed to recover those seriously injured.

Question 22

What did Shinzo Abe (Japanese PM) order in response?

(Mount Ontake Eruption)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 22

Ordered the military to assist with emergency rescue operations.

Question 23

What is the overriding important message of the eruption?

(Mount Ontake Eruption)
(Case study: Japan’s eruption of Mount Ontake (AC))

Answer 23

Even in Japan, with one of the most sophisticated monitoring and warning systems anywhere in the world, the country can be taken by surprise by the unpredictability of tectonic hazards.

Question 24

How is Indonesia similar to Japan?

(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 24

Has an archipelago straddling tectonic plate boundaries.

Indonesia also has a large number of active volcanoes; (records of around 80 that have erupted in historic times, though this may be an underestimate).

Much of the landscape of Indonesia is dominated by volcanic peaks.

Indonesia’s history, culture and the personal experience of its people is also closely tied to volcanoes.

Question 25

What fraction of of Indonesia’s inhabitants live within 100 km of a volcano that has erupted in the past 10,000 years.

(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 25

More than 3/4 of Indonesia’s inhabitants.

Question 26

Outline Indonesia’s tectonic setting.

(Indonesia’s tectonic setting)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 26

Complex, with widespread subduction along the entire 3000 km length of the Indonesian archipelago.

Question 26

Does Indonesia always experience volcanoes?

(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 26

Indonesia has suffered more eruptions causing fatalities and damage to infrastructure than any other country in the world.

Question 27

Much of Indonesia is an island arc. How did this form? What do these produce?

(Indonesia’s tectonic setting)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 27

Formed by subduction of the Indo- Australian plate beneath the Eurasian plate.

These plate movements produce very high levels of seismicity and volcanicity.

Question 28

A feature of volcanism in Indonesia is the large number of volcanoes that are highly explosive. When was this demonstrated?

(Indonesia’s tectonic setting)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 28

The cataclysmic eruption of Krakatoa in 1883, which also generated a devastating tsunami.

In the north of Sumatra, Lake Toba fills the caldera caused by the devastating eruption of that super-volcano 70,000 years ago.

Question 29

What is Merapi?

(Mount Merapi)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 29

A strato-volcano which reaches nearly 3000 m in altitude.

Question 30

What classification of volcano is Merapi? What shows this?

(Mount Merapi)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 30

Highly active, with eruption events in 1994, 1997, 2001 and 2006.

On each occasion, a dome developed in the crater, which eventually collapsed, producing pyroclastic flows.

The force of these eruptions was 3-4 VEI.

Question 31

When did Merapi erupt? Who did this mainly affect?

(Mount Merapi Eruption)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 31

The VEI 4 eruption occurred from 26 October to 12 November 2010 affected people living around the volcano.

Question 32

Pyroclastic flows, lava bombs, lahars, and ash falls all occurred as a result of the eruption. Outline each.

(Mount Merapi Eruption)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 32

Pyroclastic flows extended 4 km to the north, 11.5 km to the west, 7 km to the east and 15 km to the south.

Lava bombs were thrown 4 km from the summit in all directions.

The eruption happened at the start of the rainy season, triggering lahars fed by ash from the eruption and from earlier eruptions.

Ash falls forced the closure of Yogyakarta airport for over a fortnight and emissions of sulphur dioxide caused acid rain to fall over a large part of the region.

Question 33

Overall, how many people were killed by the eruption? How many injured? How many were made refugees (due to proximity to the volcano)?

(Mount Merapi Eruption)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 33

367 people were killed.

277 were injured.

Approximately 410,000 became refugees.

Question 34

State other impacts of the eruption.

(Mount Merapi Eruption)
(Case study: Indonesia’s eruption of Merapi (EDC))

Answer 34

Large numbers of livestock were killed and ash fall and pyroclastic flows amounting to 130 million m³ of material destroyed crops and infrastructure such as buildings, power lines and bridges.

Question 35

In Java (Indonesia) population density reaches just over how many people per km2 in rural areas?

(Why do people choose to live in tectonically active locations?)

Answer 35

Just over 1000 people/km2 even in rural areas.

Question 36

In both Indonesia and Japan millions of people have little choice but to do what?

(Why do people choose to live in tectonically active locations?)

Answer 36

Live alongside active or dormant volcanoes and experience many earth tremors.

Question 37

The slopes of volcanoes often attract settlement. How is this beneficial in Java?

(Farming)
(Why do people choose to live in tectonically active locations?)

Answer 37

Java’s volcanic soils and its tropical climate allow as many as 3 crops of rice to be grown in a year.

Weathered lava produces fertile soils especially in wet tropical regions.

Intensive farming therefore supports very high population densities.

Question 38

Japan’s agricultural sector uses what percentage of total land area? How?

(Farming)
(Why do people choose to live in tectonically active locations?)

Answer 38

Uses just 13% of the country’s land area but does so very intensively.

In part this is possible due to the high fertility of volcanic soils.

Question 39

What has been done to Japanese and Indonesian steep-sided slopes of strato-volcanoes?

(Farming)
(Why do people choose to live in tectonically active locations?)

Answer 39

They have been terraced to allow farming to be practised.

Question 40

Where have tectonically active locations seen successful tourism?

(Tourism)
(Why do people choose to live in tectonically active locations?)

Answer 40

Iceland has exploited its tectonically active environment to attract tourists.

The unexpected eruption of White Island, off the coast of New Zealand in 2019, killed 8 tourists and was a very sharp reminder that the level of development of a country and the level of its technology are no guarantee of safety for their tourists.

Question 41

Where have tectonically active locations seen unsuccessful tourism?

(Tourism)
(Why do people choose to live in tectonically active locations?)

Answer 41

White Island, off the coast of New Zealand in 2019.

The unexpected eruption killed 8 tourists and was a very sharp reminder that the level of development of a country and the level of its technology are no guarantee of safety for their tourists.

Question 42

What energy can be produced from tectonically active regions? Why?

(Energy)
(Why do people choose to live in tectonically active locations?)

Answer 42

Geothermal energy

As ‘hot rocks’ are nearer the surface in tectonically active regions.

Question 43

Iceland has developed geothermal resources to help it become what? Where else has?

(Energy)
(Why do people choose to live in tectonically active locations?)

Answer 43

Help it become 100% renewable in its production of electricity.

Japan also has had geothermal power stations since the 1960s but these were small scale.

Indonesia also has vast geothermal energy potential and is beginning to exploit this.

Question 44

Recently, geothermal resources have been receiving increasing attention. However, what is one issue that Japan faces in exploiting its geothermal energy resources?

(Energy)
(Why do people choose to live in tectonically active locations?)

Answer 44

Nearly 80% of the ‘hot rock’ locations are in national parks or protected hot spring locations.

Question 45

What percentage of Indonesia’s total electricity generation comes from geothermal?

(Energy)
(Why do people choose to live in tectonically active locations?)

Answer 45

Currently, only about 3% of Indonesia’s total electricity generation comes from geothermal but there are plans to increase this.

The 350 megawatt Sarulla power plant is planned to increase this, being set to come online in 2022, with the potential to be the world’s largest.

Question 46

What mineral is associated with volcanic eruptions? What are these used for?

(Industry)
(Why do people choose to live in tectonically active locations?)

Answer 46

E.g. sulphur.

Used in a variety of industrial processes such as the production of chemicals.

Question 47

Outline sulphur within Japan.

(Industry)
(Why do people choose to live in tectonically active locations?)

Answer 47

Japan used to mine sulphur at Matsuo but production ceased in 1972.

Question 48

Outline sulphur within East Java (Indonesia).

(Industry)
(Why do people choose to live in tectonically active locations?)

Answer 48

In east Java, Indonesia, sulphur is extracted directly from the crater of ljen volcano.

Miners cut lumps of solidified sulphur by hand from near the lake which occupies most of the crater.