eruptions

Question 1

effusive

Answer 1

• divergent plate margin
• basalt lava - low viscosity, high temperature during eruption and low silica %
• eruptions involve: gas bubbles expanding freely and lava flows
• not explosive
• frequent & can have long durations
• shield volcanoes

Question 2

explosive

Answer 2

• convergent plate margin
• acidic lava (rhyolite) with high viscosity and lower temperature during eruption and high silica %
• violent burst of gas, cone shatters
• materials extruded: ash, lava bombs and tephra’s
• infrequent
• stratovolcanoes/ composite volcanoes

Question 3

Plinian eruption

Answer 3

• gas rushes up through viscous lava and ash = fragments forced airborne from huge explosion
• produces cloud of gas and volcanic debris km’s thick
• products run down slope

Question 4

Vesuvian Eruptions

Answer 4

• powerful blasts of gas and ash clouds
• lava flow and ash falls - covers surrounding areas
• more violent than vulcanic eruption

Question 5

vulcanic eruption

Answer 5

• violent gas explosions out plugs sticky/ cooled lava
• fragments build up into cones once viscous lava solidifies
• eruption clears blocked vent and emits volcanic ash

Question 6

Strombolian eruption

Answer 6

• frequent gas explosions = runny lava into air and eventually forming a cone
• explosive eruption -> pyroclastic rock dispersed
• produces white cloud of steam

Question 7

Hawaiian eruption

Answer 7

• central activity
• runny, basaltic lava and gases escape easily
• minor pyroclastic activity

Question 8

Icelandic lava eruptions

Answer 8

• persistent fissure eruptions
• large quantities of basaltic lava build up
• Deccan Plateu and Columbia Plateu

Question 9

difference between volcanic eruption away from plate margins and on plate margins

Answer 9

• away from plate boundary the casualty of volcanic activity are hotspots
• where within the magma plume some magma is hotter than its surrounding magma = melting of crust of a moving plate margin
• on plate margin the causality of volcanic activity is plate margins moving agains’t one another causing fissures allowing magma to rise

Question 10

similarities between differing casualties of volcanic activity

Answer 10

• formation of volcanoes = plates are moving and the magma/ magma plume stay stationary
• fissures created from plates forces pushing away or towards another plates allowing magma movement