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TOFUA

TOFUA. Emily Malinowski and Mikaela Johnson Dept. of Geology, Colby College. 19 °45′00″S 175°04′30″W. GEOGRAPHY. Tofua is a Summit Caldera of a steep composite cone that forms the 8 kilometer wide Tofua Island, located in the country of Tonga 1,690 feet high 5 km by 6 km wide

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TOFUA

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  1. TOFUA Emily Malinowski and Mikaela Johnson Dept. of Geology, Colby College

  2. 19°45′00″S 175°04′30″W

  3. GEOGRAPHY • Tofua is a Summit Caldera of a steep composite cone that forms the 8 kilometer wide Tofua Island, located in the country of Tonga • 1,690 feet high • 5 km by 6 km wide • Contains a freshwater crater lake

  4. Geography Cont’d • Three major cones lie on eastern, western, and northern parts of caldera • Northern cone (Lofia) is still active • Eastern cone is dormant with three vents • Western cone is older, deeply eroded ash

  5. Plate Tectonics • Tonga was created by subduction,or where the Pacific plate is being subducted below the Australian plate • This point of converging plates is called the Tonga Trench, which is approximately 10,882 meters deep at its deepest point

  6. ORIGINS • In 1643, Tofua Island was first spotted by a European explorer, Abel Tasman • Tofua was formed after a Stratovolcano erupted in 1774, leaving the summit caldera in its place • Captain James Cook (1728-1779) witnessed this first recorded eruption of that Stratovolcano • The first to set foot on the island however was Captain William Bligh in 1789

  7. Activity • Most reported eruptions have been small, produced by the Lofia Cone • An eruption in the mid 1900s caused most of the inhabitants to evacuate • March 2009--Xavier Rosset, a Swiss adventurer, reported minor activity at Tofua • July 2011--The Tonga Meteorological Services and pilot observations noticed a cloud from Tofua rising to 1.3 km in height. • August 14th, 2012 a 3,000 foot high ash cloud was observed by a pilot flying over the Tonga Islands. There was a debate on whether the clouds were an actual eruption or smoke from fires.

  8. Tofua Formations • Hamatua Formation • Hokula Froth Lava • Kolo Formation • Lofia Formation

  9. Hamatua Formation -Pre caldera -First eruptions -Approx. 1600 feet thick Pyroxene Dacite Basaltic Andesite Pyroxene Andesite

  10. Hokula Froth Lava -Directly overlies the Hamatua Formation -Contains “Frothy Lava”

  11. Kolo Formation Lapilli Tuff-Breccia Tuff Volcanic Ash

  12. The Lofia Cone • Largest, northernmost cone • 400 feet deep • Lava floor • Fumarolic state • Pyroclastic deposits around the area

  13. Monitoring • The Hawaii Institute of Geophysics • The Wellington Volcanic Ash Advisory Centre Rock coring tool used in paleomagnetic study

  14. Life on the Island • Tofua Island has been uninhabited for thirty years, however farmers travel to grow Kava • The soil is extremely rich and fertile, with various plants an animals • There are forests, tropical bush, and desert tundra • Occasional cyclones hit the area during the hurricane season

  15. Tourism • Until 1999 a plane ran flights to Tofua, however the lack of interest shut down operations. Today tourists can visit the island by boat. • Tofua is most popular and safe for hiking and swimming. • Visitors can hike the Lofia Cone and look down into the lava

  16. Bibliography • http://www.volcanodiscovery.com/tofua-eruptions.html • http://en.wikipedia.org/wiki/Tofua • http://www.volcano.si.edu/world/volcano.cfm?vnum=0403-06= • http://tonga.southpacific.org/haapai/tofua.html • http://proven-travel.com/tofua/ • http://teachtonga.com/geography.htm • http://theextinctionprotocol.wordpress.com/2012/08/14/62-tofua-volcano-erupts-sending-ash-cloud-3000-feet-above-tonga-islands/ • https://docs.google.com/a/colby.edu/viewer?a=v&pid=gmail&attid=0.1&thid=13c735945b0c5568&mt=application/pdf&url=https://mail.google.com/mail/u/0/?ui%3D2%26ik%3D4b2b57da4b%26view%3Datt%26th%3D13c735945b0c5568%26attid%3D0.1%26disp%3Dsafe%26realattid%3Df_hcdrqwz20%26zw&sig=AHIEtbQrpaWbvTJe1j2K1YVhV-aSxu19IA • PICTURES: • http://www.volcano.si.edu/world/volcano.cfm?vnum=0403-06=&volpage=photos&photo=107097 • http://www.travelgrove.com/blog/wp-content/uploads/tofua.jpg • http://www.google.com/imgres?q=tonga+islands&hl=en&client=safari&sa=X&tbo=d&rls=en&biw=1280&bih=663&tbm=isch&tbnid=qJEr2W_-XiWzkM:&imgrefurl=http://geography.howstuffworks.com/oceania-and-australia/geography-of-tonga.htm&docid=6I3mFBcNKp4yCM&imgurl=http://static.ddmcdn.com/gif/willow/geography-of-tonga0.gif&w=273&h=228&ei=_4_9UJHfHozO0QH7m4HoBg&zoom=1&iact=rc&dur=454&sig=109138024570501102308&page=1&tbnh=143&tbnw=171&start=0&ndsp=20&ved=1t:429,r:2,s:0,i:104&tx=136&ty=91 • http://www.google.com/imgres?q=tofua&hl=en&client=safari&tbo=d&rls=en&biw=1280&bih=663&tbm=isch&tbnid=ippFzUJAzAZAEM:&imgrefurl=http://www.nautilussubmarine.com/forum/viewtopic.php%3Ff%3D36%26t%3D382%26start%3D20&docid=Efn9jwbVYxmIuM&imgurl=http://www.photosntravels.com/dancyn/albums/album34/tofua_005.jpg&w=1024&h=768&ei=IZD9UOCSKO7C0AHhsYDgDQ&zoom=1&iact=rc&dur=345&sig=109138024570501102308&page=1&tbnh=139&tbnw=200&start=0&ndsp=25&ved=1t:429,r:0,s:0,i:81&tx=82&ty=33 • http://www.google.com/imgres?q=captain+cook&hl=en&client=safari&tbo=d&rls=en&biw=1280&bih=663&tbm=isch&tbnid=j110B8N5wVz4fM:&imgrefurl=http://en.wikipedia.org/wiki/James_Cook&docid=DyaNqdXffoAo0M&imgurl=http://upload.wikimedia.org/wikipedia/commons/thumb/7/76/Captainjamescookportrait.jpg/220px-Captainjamescookportrait.jpg&w=220&h=275&ei=m5D9UJvBGfLh0wHE8ICQDQ&zoom=1&iact=hc&vpx=4&vpy=147&dur=46&hovh=220&hovw=176&tx=81&ty=140&sig=109138024570501102308&page=1&tbnh=134&tbnw=108&start=0&ndsp=29&ved=1t:429,r:0,s:0,i:147 • http://www.lonelyplanet.com/maps/pacific/tonga/ • http://geology.about.com/od/more_igrocks/ig/extrusives/Tuff-from-Green-Valley.htm • http://www.volcano.si.edu/volcanoes/region04/tonga/tofua/3402tof4.jpg • http://www.volcano.si.edu/volcanoes/region04/tonga/tofua/3607tof1.jpg • http://tbarnes.co.uk/TimsPages/TRAVEL/Tonga/plane.htm

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