Transcript ES9 18 Volcanoes II (Jecho)

Volcanoes II
By: Jericho C. Ventanilla
wagnerguatemala.weebly.com
Parts of a typical volcano
(volcanochapter3.weebly.com)
Vent
- also releases ash clouds, volcanic
ashes, cinders, and bombs
- divided into two parts:
- Central Vent – main
- Side Vent – alternative
Conduit or Pipe
- connects the magma chamber to
the vent of the volcano
- the purpose for this is to lead
the magma to the vent and out to
the surface
Crater
- a depression at the central
vent of the volcano shaped by
volcanic activity
- two types of crater:
- Summit – top
- Flank – side
Caldera (en.wikipedia.org)
- formed by the collapse of land,
following a volcanic eruption
gaia3d.co.uk
marlimillerphoto.com
Three main types of volcanoes
(geography.learnontheinternet.co.uk)
Shield Volcanoes
Composite Volcanoes (stratovolcanoes)
Cinder cones (extremescience.com)
- low with gentle sloping sides
- from layers of ash
- classic and cone-shaped peaks
- from layers of lava
- explosive due of thick and high viscous lava - eruptions are pretty small potatoes
- typically non-explosive
- pose a threat to nearby life and property
- small and hill-sized
- fatalities rarely occur
- examples:
- examples (en.wikipedia.org):
- examples:
- Mount St Helens (USA)
- Paricutin (Mexico)
- Mount Kilauea (Hawaii, USA)
- Mount Pinatubo (local)
- Mount Mayabobo (local)
- Mt Bulusan (local) (answers.com)
movdata.net
en.wikipedia.org
conniemcarthur.com
markmaranga.com
paricutinmexico.weebly.com
Cesar C. Cambay/panoramio.com
Dangers that volcanoes pose
(en.wikipedia.org)
Nuée ardente (pyroclastic flow)
Causes
- fountain collapse
- frothing
- gravitational collapse
- directional blast
bgs.ac.uk
Effects
- larger flow can travel for hundreds of kms
- none on the scale have occurred for several
hundred thousand years
- kinetic energy of the moving boulders will
flatten trees and buildings in their path
blog.mailasail.com
Lahar (mudflow)
Causes
- snow and glaciers can be melted by lava
- flood caused by glacier (glacier run)
- water from crater lake, combined with
volcanic material in an eruption
- volcanic landslides
Effects (volcanoes.usgs.gov)
imgbuddy.com
- can lead of to increased deposition of
sediment
- can block tributary streams
- can bury valleys and communities with debris
photovolcanica.com
Volcanic landforms
(w3.salemstate.edu)
Calderas
- Crater Lake – violent eruptions accompanied by collapse
- Hawaiian – subsidence after the magma supporting the summit
seeks an alternative route
- Yellowstone – largest with diameters ranging form 10 to 100 km
Fissure eruptions (volcano.si.edu) and basalt plateaus
- produced extensive lava fields
- fluid basaltic lava extruded from crustal fractures called
fissures
- examples:
- Columbia plateau
- Deccan plateau
nvonews.com
hilo.hawaii.edu
Volcanic pipes and necks
- pipes connect a magma chamber to the surface
- necks (e.g., Ship Rock, New Mexico) are resistant
vents left standing after erosion has removed the
volcanic cone
yellowecho.com
Relationship between plate tectonics and volcanic activity
Pacific Ring of Fire (worldatlas.com)
- notorious for volcanic eruptions
- 450 volcanoes
- approximately 75% of the world’s active volcanoes
Volcanoes at convergent plate boundaries (en.wikipedia.org)
- island arc
- archipelago
- tectonically created arc-shaped mountain belts that are
partly below sea level
- continental volcanic arc
- petrogenesis
- partial melting of the subducting generates
primary magma
- magmatism
- generate the primary magma
Volcanism at divergent plate boundaries (ck12.org)
- volcanoes erupt at mid-ocean ridge
- the frequent volcanic eruptions are a result of hot spot
activity and separating plates (kids-fun-science.com)
Intraplate volcanism (geology.sdsu.edu)
- mantle plume
- generated in the lower mantle
- rise slowly through the mantle by convection
- hotspots
- regions of voluminous volcanism
cbc.ca
geology.sdsu.edu
Living with volcanoes?
- 10% of the world's population lives in the vicinity of an active volcano (gtr.rcuk.ac.uk)
- Agriculture (volcano.si.edu)
- provide soil nutrients
- volcanic soils cover more than 1.5 million sq km
- Volcanic hazards (volcanology.geol.ucsb.edu)
- Volcanic gas
- Tsunamis
- Volcanic Lighting
- Monitoring volcanic activities (volcanoes.usgs.gov)
- important because could affect hundreds of thousands of people
Mount Pinatubo (1991) (newworldencyclopedia.org)
Damaged:+73,000
Victims:722 (ngdc.noaa.gov)
Mount St. Helen (news.discovery.com)
Damaged: S3 billion
Victims:57
Does volcanoes also change climate?
- The answer is YES
- Once it gets into the stratosphere, sulphur dioxide from a volcano mingles with
water, forming tiny sulphate particles (economist.com)
- The cooling influence will dominate for the period immediately but the warming
impact will last much longer (theguardian.com)
- Examples(geology.sdsu.edu):
- Mt Tambora (1815) – 1816, year without summer
- Mt St Helens (1980) – lowered temperature by 0.1 Celsius
- El Chichon (1982) – lowered global temperature 3 to 5 times as much
- Mt Pinatubo (1991) – decreased world temperatures by about 1 degree
Centigrade over the subsequent 2 years
Refrences
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wagnerguatemala.weebly.com
volcanochapter3.weebly.com
gaia3d.co.uk
marlimillerphoto.com
geography.learnontheinternet.co.uk
answers.com
movdata.net
en.wikipedia.org
conniemcarthur.com
markmaranga.com
paricutinmexico.weebly.com
Cesar C. Cambay/panoramio.com
extremescience.com
volcanoes.usgs.gov
bgs.ac.uk
blog.mailasail.com
imgbuddy.com
photovolcanica.com
w3.salemstate.edu
volcano.si.edu
nvonews.com
hilo.hawaii.edu
yellowecho.com
worldatlas.com
cbc.ca
ck12.org
kids-fun-science.com
geology.sdsu.edu
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gtr.rcuk.ac.uk
volcanology.geol.ucsb.edu
newworldencyclopedia.org
ngdc.noaa.gov
news.discovery.com
economist.com
theguardian.com
Thank you for listening and I am open
for questions