Chapter 2 - Volcanoes

Cyclone book, junior cert/ junior cycle

Volcanologist - definition

Scientists that studies volcanoes

Mid ocean ridge - definition

When plates separate, lava pours out and builds up along cracks on earth’s surface forming a ridge

Vent - definition

Small hole lava violently forces through, forming volcanic mountain

Lava - definition

Magma reaching the surface and cools and hardens

How are volcanic mountains formed

1. 2 plates separate or collide, magma rises from mantle to fill space that opens up in crust (vent). Causes eruption that can be violent due to great pressure of magma in mantle

2. Magma wells up from magma chamber and reaches surface. Cools and hardens to form lava

3. After many eruptions, layers of ash and lava build up and forms vent. Cone shaped mountain forms with crater on top where lava flows

Active volcano - time period

Eruption within last 10000 years

Active volcano - example

Mount St Helens, North America

Dormant volcano - time period

Not erupted within 10000 but expected to erupt again

Dormant volcano - example

Kilimanjaro - Tanzania

Extinct - time period

Never expected to erupt again

Extinct volcano - example

Mount Kenya, Kenya

Mid ocean ridge- example

Mid Atlantic ridge - Eurasian and North American plates separating

How are volcanic island formed

Submarine volcanoes and mountains build up and rise above sea level

Volcanic island - example

Iceland

Pacific Ring of Fire - definition

Horseshoe shaped area containing many plate boundaries. Contains 75% active volcanoes, 90% earthquakes occur

Date - E15

14 April 2010

E15 eruption description

Violent and explosive. Very little lava. Huge amounts ash sent kilometers high. Winds blew ash south eastwards towards Europe

E15 - VEI scale

3-4

VEI - meaning

Volcanic explosivity index, measures eruptions from 0-8 (weakest-strongest)

E15 - positive social impacts

Reduce unemployment: tourism because eruption created jobs

Increased tourism and unemployment: promo campaign led to big increase foreign tourists. Less than 500000 in 2008. 1.8 million in 2016

E15 - Positive economic impacts

Generated income for local community: E15 visitor centre built as tourist attraction

Fertile soil: Ash and lava rich in nutrients, soil in volcanic areas fertile and good for agriculture

E15 - negative social impacts

Contaminated water supply: Ash polluted local water. Animals couldn’t drink from streams

Evacuation of locals: 500 farmers and locals had to leave home. Wore masks to avoid choking on ash

E15 - negative economic impacts

Cancelled flights: 100000 flights to and from Europe cancelled because poor visibility and fear tiny ash would clog airplane engines. Cost airlines and businesses €145 million day

Loss of earnings: Counties, e.g. Kenya, that sell perishables affected. Flight ban meant produce transported quickly by plane not sold. Million flower stalks unsold in first 2 days