ICELAND Divergent Plate Boundaries n n MidAtlantic Ridge

ICELAND

Divergent Plate Boundaries n n 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 n n 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 n n 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 n n n n Krafla Loki-Fogrufjoll Grimsvotn (and Laki) Hekla Vatnafjoll Katla Vestmannaeyjar (Surtsey, Heimaey)

1973 Heimaey Eruption n n 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 n n n Volcano started erupting June 8, 1783 after a week of earthquake activity 15. 5 mile long fissure opened with lava flows 25 km 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 n n Dramatic scenery created by volcanic eruptions attract tourists Lava and ash deposits provide valuable nutrients for soil

Positive Impacts Of Volcanic Eruptions n The high level of heat and activity inside Earth, close to a volcano, can create opportunities for geothermal energy

n n n Negative Impacts Of Fatalities Volcanic Eruptions 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 n n n 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 n n n n n http: //homepage. mac. com/rmshultz/blogwavestudio/LH 20050212162819/LHA 20050703211002/ http: //earthobservatory. nasa. gov/Newsroom/New. Images/images. php 3? img_id=16443 http: //en. wikipedia. org/wiki/Geography_of_Iceland http: //www. iceland. is /country-and-nature/Geology/ http: //www. iceland. is/country-and-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/heimaey 1. html http: //antwrp. gsfc. nasa. gov/apod/ap 020121. html http: //volcanoes. usgs. gov/About/What/Monitor/monitor. html http: //www. bbc. co. uk/schools/gcsebitesize/geography/platetectonics/volcanoesrev 5. shtml http: //pubs. usgs. gov/publications/text/understanding. html#anchor 15039288 http: //www. platetectonics. com/oceanfloors/iceland. asp http: //quakeinfo. ucsd. edu/~gabi/erth 15/lecture 09/volcanoes. html http: //volcano. und. nodak. edu/vwdocs/Gases/laki. html http: //tlc. uwaterloo. ca/is 303 a/design/s 2001/Volcano/Heimaey_7_Location. htm

Group Members Christina Saylor Brian Duncan