Tectonic Hazrads- Volcanos

Question 1

Tell me about pyroclastic flows- primary hazard

Answer 1

-clouds of superheated rock & ash
-occur when explosive eruptions cause lava to blast through the air & cool quickly into rock and ash
- being heavy they flow down hill and can flatten trees and buildings
- unpredictable
- intense heat can burn animals and people and scorch the landscapes

Question 2

Tell me about lava flows PH

Answer 2

• travel down slope and burns everything in its path
• eventually solidifies leaving a layer of new rock on the surface

Question 3

Tell me about ash fall pH

Answer 3

• doesn’t account for many deaths during eruptions but can create problems in the medium term
• respiratory problems due to particles of ash
• Poor visibility
• landscapes covered in metres of ash and loss of crops
• closure of airports. Ash clocks engines in aeroplanes posing a hazard

Question 4

Tell me about toxic gases pH

Answer 4

• CO2, hydrogen and sulfide are released at explosions
• people suffocate
• often difficult to detect the gas as some are invisible and odourless

Question 5

Tell me about lahas SH

Answer 5

• floods of water mixed with volcanic debris
• contain rocks, ash, mud and debris
• form quickly
• close down the volcanoes into surrounding valleys at high speeds
• major cause of death
• travel tens of kilometres

Question 6

Tell me about jokulhlaups SH

Answer 6

• insulation eruptions the water produced from mounting ice becomes trapped in a lake between of the volcano and surrounding glacier
• eventually this water is released as a violent flood

Question 7

Tell me about basalitic magma

Answer 7

• Is hotter
• Is more runny
• travels faster
• at diverging boundaries
• comes from the mantle

Question 8

Tell me about volcanic landslides SH

Answer 8

• triggered by pressure build ups as magma rises to the surface
• slopes can bulge or shift suddenly triggering a mass movement of rock and volcanic debris

Question 9

Tell me about environmental impacts

Answer 9

Destruction of forests
Flooding
Areas burnt by lava

Question 10

Tell me about economic impacts

Answer 10

-Damage to crops
-Roads, rails, airports =inaccessible/ unstable
- loss of businesses

Question 11

Tell me about social impacts

Answer 11

• injuries/ health issues
• homelessness
• loss of services such as schools

Question 12

Tell me about monitoring, predicting and warnings of gases

Answer 12

• any changes/ increases in gas being emitted can be assigned that an eruption may occur
• magma moving towards the surface will force out more gas

Question 13

Tell me about monitoring, predicting and warnings of ground vibrations

Answer 13

• seismometers can indicate wether earthquakes are becoming more frequent or bigger

Question 14

Tell me about monitoring, predicting and warnings of lahars

Answer 14

• lahars sensors can give minutes of warnings that a labar is building up and moving down slips

Question 15

Tell me about the disaster management cycle

Answer 15

• implementing all four elements (response recovery mitigation preparedness) minimizers risk and vulnerability
• monitoring a volcanoes allowed to prediction of an eruption and warnings
• includes mitigation strategies and planning for rescue recovery so that resilience is increased
• dependence between all four factors
• if one is left out the effectiveness of others strategies as reduced

Question 16

Tell me about the mitigation of lava flows

Answer 16

• artificial barriers
• must be done quickly
• evacuate areas

Question 17

Tell me about the mitigation of ash fall

Answer 17

• global system of reporting ash clouds is in place to worn air traffic and managers and pilots
• close of airports eliminates risk
• people advised to stay indoors to avoid respiratory difficulties
• hospitals are warned to prepare for increase in patients

Question 18

Tell me about the mitigation of lahas and jokulhlaups

Answer 18

• diverging channels built using reinforced concrete to divert them away from buildings and towns
• permeable screens/dams can be installed across rivers so that water can pass through but large debris trapped
• this produces the power of lahars and jokulhlaups downstream