Iceland divergent Plate Boundaries Mid-Atlantic Ridge divides North American and Eurasian tectonic plates

ICELAND

Divergent Plate Boundaries

• Mid-Atlantic Ridge divides North American and Eurasian tectonic plates

• These tectonic plates are moving away from each other causing rift zones

• Magma rises from rift zones causing volcanism and earthquakes

• Iceland is growing about one inch per year as a result of seafloor spreading

Rift Valley

Geological History

• Iceland is 20-25 million years old based on the time-span of active volcanism

• Over 1/3 of Iceland’s 40,000 square miles is volcanically active

• Iceland is a hotspot as it sits on a mantle plume with volcanic eruptions occurring about every 5-10 years

• Iceland is built mostly of volcanic rocks, predominately basalts (Igneous Rocks)

Land Of Fire & Ice

• Iceland is far enough north to be covered by snow

• The heat generated by the Mid-Atlantic Ridge keeps the country in a constant state of thaw

Major Volcanoes In Iceland

• Krafla

• Loki-Fogrufjoll

• Grimsvotn (and Laki)

• Hekla

• Vatnafjoll

• Katla

• Vestmannaeyjar (Surtsey, Heimaey)

1973 Heimaey Eruption

• Volcano started erupting January 23, 1973

• 1600 meter long fissure with early reports of 50-150 meter high glowing fountains

• Eruptions ended June 26,1973 with a total eruption product volume of 250 million cubic meters

• 417 homes destroyed and the remainder of the surrounding towns were hit with lava bombs and covered in ash

• Icelanders sprayed sea water on the lava to try to slow and stop the movement

1973 Heimaey Eruption

1783 Laki Eruption

• Volcano started erupting June 8, 1783 after a week of earthquake activity

• 15.5 mile long fissure opened with lava flows 25km long

• Total estimated volume of produced lava was 3.6 cubic miles

• Gases released slowed grass growth and killed farm animals

• 7 months of eruptions caused crop failure

• Famine kills 10,000 people reducing Iceland’s population by 20%

Recent Iceland Eruptions

Positive Impacts Of Volcanic Eruptions

• Dramatic scenery created by volcanic eruptions attract tourists

• Lava and ash deposits provide valuable nutrients for soil

Positive Impacts Of Volcanic Eruptions

• The high level of heat and activity inside Earth, close to a volcano, can create opportunities for geothermal energy

Negative Impacts Of Volcanic Eruptions

• Fatalities

• Lava flows and lahars (mudflows) can destroy settlements and clear areas of woodland or agriculture

• Human and natural landscapes can be altered or destroyed

Volcano Monitoring

• Hydrologic Monitoring – early flood warning for people downstream of an active volcano

• Ground Deformation – monitors ground movements to help predict an eruption

• Seismicity – measures earthquake activity; earthquake activity almost always increases before an eruption

• Gas – monitors changes in the release of certain gases to provide eruption warnings

• Remote Sensing – using satellites to monitor volcanoes by sensing electromagnetic energy from the surface of a volcano

References

• http://homepage.mac.com/rmshultz/blogwavestudio/LH20050212162819/LHA20050703211002/

• http://earthobservatory.nasa.gov/Newsroom/NewImages/images.php3?img_id=16443

• http://en.wikipedia.org/wiki/Geography_of_Iceland

• http://www.iceland.is/country-and-nature/nature/Geology/

• http://en.wikipedia.org/wiki/Divergent_boundary

• http://en.wikipedia.org/wiki/Mid-Atlantic_Ridge

• http://en.wikipedia.org/wiki/Rift

• http://en.wikipedia.org/wiki/Iceland_hotspot

• http://vulcan.wr.usgs.gov/Volcanoes/Iceland/Maps/map_iceland_volcanoes.html

• http://vulcan.wr.usgs.gov/Volcanoes/Iceland/description_iceland_volcanics.html

• http://notendur.centrum.is/~edda/heimaey1.html

• http://antwrp.gsfc.nasa.gov/apod/ap020121.html

• http://volcanoes.usgs.gov/About/What/Monitor/monitor.html

• http://www.bbc.co.uk/schools/gcsebitesize/geography/platetectonics/volcanoesrev5.shtml

• http://pubs.usgs.gov/publications/text/understanding.html#anchor15039288

• http://www.platetectonics.com/oceanfloors/iceland.asp

• http://quakeinfo.ucsd.edu/~gabi/erth15/lecture09/volcanoes.html

• http://volcano.und.nodak.edu/vwdocs/Gases/laki.html

• http://tlc.uwaterloo.ca/is303a/design/s2001/Volcano/Heimaey/Heimaey_7_Location.htm

Group Members

• Christina Saylor

• Brian Duncan