3.1.5.3 Volcanic hazards

Primary hazards

Lava flow, pyroclastic flow, tephra, toxic gases

Pyroclastic flow features

700-800C, up to 700km/h avalanche of gas and ash formed by eruption column collapsing as it becomes too dense to be supported by rising gas

Basaltic lava

Low viscosity and flows long distances to form shield volcanoes

Rhyolitic lava

High viscosity and flows short distances to form composite volcanoes

Secondary hazards

Lahars, Glacial floods, Landlsides

Primary effects

Ecosystems damaged, infrastructure and homes destroyed, Deaths

Secondary effects

Water acidified, Greenhouse effect, Job loss, Tourism boost, Flight disruption, Agricultural impacts

Shield volcanoes

Shallow and broad, gentle

Composite volcanoes

Steep and narrow, explosive

Distribution of volcanoes

Along constructive and destructive boundaries alongside hotspots

Magnitude of volcanoes

Measured by VEI, low magnitude effusive

Predictability signs of volcanoes

Ground expansion, gases released, temperature of water

Measuring devices

Tiltmeters, gas spectrometers, thermal camera

Management

Prevention, Preparedness, Mitigation, Adaption

Preparendess

Monitoring to increase warnings, education and evacuation drills, training response teams

Mitigation

DIrect intervention, exclusion zones, strengthening buildings

Adaption

Cultivating fertile soil, encourage tourism, Change professions at risk