volcanic processes. water water can be heated by magma or lava. process of heating water can create:...
TRANSCRIPT
Volcanic
Processes
WaterWater• Water can be heated
by magma or lava. Process of heating water can create:– Geysers– Hot Springs– Fumaroles– Mud Pots
• Heated water can cause hydrothermal alteration
GasesGases• Released from within
magma as pressure and temperature changes– Can cause explosive
eruptions– Can poison plants and
animals at surface
Lava FlowsLava Flows• Streams of molten rock
– Some flow smoother and faster than others
• Depends on – Temperature– Chemical make-up
– Everything in the path of the lava is in danger of being:
• Knocked over
• Surrounded
• Buried
• Burned/melted
TephraTephra• ‘Ash Fall’ and/or ‘Eruption
Column’• Explosions and “Stuff” that is
Ejected During Eruptions• Tephra- lava and solid
material, blasted into the air– Volcanic Ash/Dust- Small and
very small material ejected during an eruption
– Volcanic Bombs- Pebble sized to massive boulders of ejected material
TephraTephra
• Particles of shattered rock and cooled lava.
• Falls at air temperature at distance from the vent.
• Non-poisonous to touch or breathe.
• Irritates eyes, breathing difficult, reduces visibility, abrasive, clogs filters.
Pyroclastic FlowsPyroclastic Flows• ‘Ash Flow’• Avalanches of hot gases
and rock.• Form by collapse of lava
flows or eruption columns.• Destroy all in their path by
burial, burning and asphyxiation.
• Melted snow and ice and indirectly cause lahars.
• Can move at 80 km/h and reach temperatures of 700º C
LandslidesLandslides• Flow of rock and debris
‘debris avalanche’• Hydrothermal
alteration- when groundwater becomes heated and acidified, alters the composition of rocks, and makes them susceptible to collapse.
LaharsLahars• ‘Mud Flows’ or
‘debris flow’
• A fast-moving slurry of mud, boulders and water
• Formed by – Volcanically--melted snow
and ice– Landslides– Glacial floods
Lahars
• May pick up more debris while moving down slope
• Water can be very hot • Flows in river valleys,
but can travel great distances from the volcano
Semeru Volcano, Indonesia Video by Frank Lavigne
TsunamisTsunamis• Eruptions can create
huge waves in large bodies of water located near a volcano
A Common Scenario During Eruptions…
• Lava flows on steep slopes break apart and transform into ...
• …avalanches of hot rock and gases called pyroclastic flows
• …that melt snow and ice and mobilize loose rock to form…
• Lahars.
Volcanoes give us warning signs
• Volcanoes often show signs that they are getting to erupt days to months or more in advance.
• Scientists evaluate signs of unrest and look for:• Increased emission of volcanic gases• Increased earthquake activity• Swelling of the volcano.
Limiting Danger Limiting Danger from Hazardsfrom Hazards
• Warning Warning – Know when event is happening
• Research Research – Know what will happen in an event
• Education Education – Know what to do when an event
happens