People continue to live in tectonically active locations for a range of sociocultural, economic
and environment reasons, such as:
• Weathered lava produces fertile soils
• Volcanoes provide opportunity for economic activity such as tourism
• Tectonically active areas produce geothermal power
• Volcanic eruptions supply minerals such as sulphur, used in a variety of industries
There are a range of impacts people experience as a result of volcanic
eruptions:
Case Study – Japan, Mount Ontake:
Tectonic Setting =
4 tectonic plates meet in 3 subduction zones.
N.West Ring of Fire.
110 active volcanoes
Over 2000 years, 1200 eruptions.
Mount Ontake =
Classic strato-volcano, over 3000m.
On Honshu (Japan’s largest island).
N.American and Eurasian destructive boundary.
First Eruption in 1979, last in 2014.
27th September 2014 eruption impacts =
Worst in Japan in 90 years.
No alerts or warnings
Killed 63 people (Pilgrims and climbers)
40cm ash fall, pyroclastic flow, volcanic bombs and lahars blocked escapes. (Lahars can
occur even without eruption during long periods of precipitation due to loose ash).
Reduced Visibility, air space closed.
Toxic gas inhalation (fatal).
Why live there?
Total Population = 127 million
7000 live on volcano for fertile soil (terraced for farming)
Tourism for Sakurajima (low magnitude lava flow and jobs)
Geothermal resources (80% protected by National Parks)
Mineral Mining
Hot springs (Toyako Onsen, Mount Usu)
Case Study – Indonesia, Mount Merapi:
Tectonic Setting =
Subduction along total 3000km of archipelago.
Indo-Australian below Eurasian along equator
¾ of population within 100km of volcano.
1171 eruptions, 80% since 1900.
Mount Merapi =
Srato-volcano, 3000m high.
Active summit lava dome collapses to pyroclastic flows.
Central Java and Yogyakarta border.
68 eruptions since 1548.
26th October 2010 eruption =
Pyroclastic flows 15km South.
Lava bombs thrown 4km
Lahars in rainy season
Ash falls closed Yogakarta airport
Acid Rain destroyed more crops- toxic gases mixed with atmospheric moisture
367 killed, 410,000 became refugees.
Livestock killed and 130 million m3
crops destroyed.
Infrastructure damage.
Why live there?
Total Population = 256 million
Fertile Soils on equator (2-3 crops per year).
Geothermal 3% of power (Sarulla to be world’s largest plant in 2022)
Cultural attraction
Government work (volcanologists monitor Merapi)
Village and family bonds