🟠✅Natural Hazards - Volcanic Hazards Flashcards

Question

Tsunami

Answer 1

Sea waves generated by violent volcanic eruptions. Eg. Krakatoa (Indonesia) in 1883 killled 36,000. This tsunami was up to 3.5m high

Answer 2

Pyroclastic flows can cause flooding as a secondary effect because all the materials coming down can block rivers and lakes causing swelling. They can also melt glaciers and ice caps that cause flooding.

Answer 3

Volcanoes emit gases which include sulfur. When this combines with atmospheric moisture, acid rain results

Answer 4

Pinatubo 1991 20 million tonnes of sulfur dioxide and ash 12 miles Very powerful - reached the lower stratosphere. Close of ash spread out - reflected incoming radiation back to space which lowers the earths temperature. Sulfur dioxide converted to sulfur aerosols - reflected radiation back to space - also lowered earths temperature. Northen hemisphere (1992/1993) lower temperatures. Absorbs infrared radiation emitted from earth - stopping it reflecting back to earth = cooling 2 years for all ash to be removed from stratosphere (short term).

Answer 5

Lava flow Pyroclastics Ash Gas Tephra

Answer 6

Lahar Tsunami Flooding Acid rain Climate change

Answer 7

Eyjafjallajokull (Iceland) April 2010 Mid-Atlantic ridge, divergent (constructive plates) - North American and Eurasian plates. Hot spot underneath Iceland that feeds the magma changed causing more volcanic activity. 1660m tall / ariel extent - 40Km2 / 2.5km wide caldera opening at the top Southern part of Iceland.

Answer 8

Risk - probability of loss Vulnerability - reduced by capacity, human + physical profile socec systems HIC - advanced / industrialised Disaster preparedness, sophisticated Effusive eruptions (runny) Basic lava - lower silica content South Iceland Sparsely populated - local impacts minimised Ash - difficult to manage and control

Answer 9

Primary Ash is carried away from the volcano it disperses and becomes in wisible but it can be sucked into the engines of aircraft endangering their operation / Huge amounts of ice were melted causing floods to rush down the nearby rivers, requiring nearly 1,000 people to be evacuated. The ash contaminated drinking water supplies. Ash caused respiratory illnesses for some locals. Cancelled flights left many stranded in different countries. Secondary Evacuation of farmers and their livestock due to ash / Visibility decreased

Answer 10

Primary Farmland destroyed / flights stopped. Secondary Many European countries were forced to shut down their air space because of the ash; the largest such shut down since World War I. It has been estimated that this cost the airlines £130 million per day for the six days that the airspace was closed. This affected several million people and had knock-on travel effects across the globe. Estimated £102million loss in London due to less tourists.

Answer 11

Primary Volcanoes are covered by ice caps feeding glaciers, so when they erupt much ice ice melts so flooding and huge ash clouds. As the magma hits the ice it suddenly cools, forming a glass-like material which instantly disintegrates. Explosions of gas within the main vent pulverise the fragments into very tiny particles. As the gas and steam blown from the vent carry this ash into the atmosphere it can rise to great heights where it is caught in high-altitude winds (jet stream). Debris flows Secondary 20 farms were destroyed by flooding and ash / part of main route 1 destroyed / government paid to dredge rivers

Answer 12

Area around the volcano was evacuated - 700 people were evacuated from the disaster zone, more had to evacuate in the middle of the night due to flash floods. European Red Cross Societies mobilised volunteers, staff and other resources to help people affected directly or indirectly by the eruption of the Eyjafjallajökull glacier volcano. The European Red Cross provided food for the farming population living in the vicinity of the glacier, as well as counselling and psychosocial support, in particular for traumatised children.

Answer 13

Icelandic Met Office / BGS : On the scientific front, there has been a notable increase in volcanic-cloud research since Eyjafjallajökull. Overall, this eruption has prompted the aviation industry, regulators, and scientists to work more closely together to improve the manner in which hazardous airspace is defined, forecast, and communicated. International Civil Aviation Organization A specialized agency of the United Nations. It changes the principles and techniques of international air navigation and fosters the planning and development of international air transport to ensure safe and orderly growth. ICAO formed the International Volcanic Ash Task Force (IVATF) in May 2010, charging it to examine how best to define hazardous airspace and manage aviation risk. The IVATF included representatives from government and industry groups involved in aviation regulation, operations, and scientific investigations.

Answer 14

Diggers were in position to dam rivers. Texts were sent to locals with a 30 minute warning.

Answer 15

The ash made the soil so fertile that farmers could produce rapeseed oil and grapes. Channel tunnel and ferries did extra business

Answer 16

Less aircraft noise and 2.8 million tonnes less CO2 due to flight bans. Fertiliser for the surrounding land wasn’t needed

Answer 17

Violent volcanic eruptions One plate is forced beneath the other, descending plate releases water and other volatiles decreasing the mantle melting point - magma and volcanic eruptions.

Answer 18

N/A - no magma so no volcano

Answer 19

Mild volcanic eruptions. Plates spreading - magma is able to rise up due to gaps in the earths crust.

Answer 20

This spheres in the illustration represent the volume of erupted tephra. With each step in the scale representing an exclusivity increase of 10 times, of VEI5 is roughly 10x more explosive than a VEI4, and 100x more explosive than a VEI3.

Answer 21

Frequency of eruptions varies per volcano. Volcanoes are classed as either active, dormant or extinct. An estimated 50-60 volcanoes erupt each month, meaning volcanic eruptions are always frequent (and some volcanoes erupt constantly). Usually, a higher frequency eruption means the eruptions are effusive whereas low frequency means the eruptions are explosive.

Answer 22

Volcanic eruptions are regular in that the eruptions on each type of boundary are similar (e.g. eruptions on destructive boundaries will regularly be explosive) Sometimes eruptions may be irregular and not fit patterns.

Answer 23

Regularity of eruptions can help estimate when eruptions will take place (i.e. every 10 years). Seismic activity, gases releasing, elevation etc. can all indicate an imminent eruption, but there is no definite predictions to a volcanic eruption.