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(Many slides courtesy of Scott Rowland, University of Hawaii at Manoa)

Formation & Evolution of the Hawaiian Islands Barbara Bruno Hawaii Institute of Geophysics & Planetology. (Many slides courtesy of Scott Rowland, University of Hawaii at Manoa). Hotspots. “Conveyor Belt” Model. ~5 my. ~4 my. ~3 my. ~2 my. ~1.5 my. ~1 my. ~0.5 my. ~0 my.

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(Many slides courtesy of Scott Rowland, University of Hawaii at Manoa)

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  1. Formation & Evolution of the Hawaiian IslandsBarbara BrunoHawaii Institute of Geophysics & Planetology (Many slides courtesy of Scott Rowland, University of Hawaii at Manoa)

  2. Hotspots

  3. “Conveyor Belt” Model

  4. ~5 my ~4 my ~3 my ~2 my ~1.5 my ~1 my ~0.5 my ~0 my

  5. How fast is O‘ahu moving? Speed = Distance Time

  6. Meiji Seamount (60-70 Ma) Kaua‘i (5-6 Ma) Pihemanu (Midway) (~27 Ma) E M P E R O R S E A M O U N T S Hawaiian-Emperor bend (~48 Ma) Hawai‘i (<1 Ma) H A W A I I A N R I D G E

  7. Mayon, Phillipines Photo by Dan Johnson

  8. Photo by S. Rowland

  9. Thurston Lava Tube

  10. - Scott K. Rowland, University of Hawai‘i at Manoa Photo by S. Rowland

  11. Ash Fallout from Mt. St. Helens, 1980 (Tarbuck & Lutgens)

  12. Mt. Mazama (Crater Lake)

  13. Louwala-Clough (Mt. St. Helens) was once the maiden Loowit, who was turned into this beautiful volcano She was fought over by two warriors: Wy’east (Mt. Hood), who sends lava streams and throws hot stones Pahto (Mt. Adams), who mainly hunches over gloomily

  14. Popocatépetl is active, and has been erupting off and on since the mid 1990s

  15. Volcan Agua (with Pacaya beyond) Photo: Bruce Nelson http://volcano.und.edu/vwdocs/volc_images/south_america/guat/agua.html

  16. What are some questions that come to mind? Why do some volcanoes produce lava? Why do others produce pyroclastics? Why do volcanoes have different shapes?

  17. VOLCANO EXPLOSIVITY • Magma rises & gas bubbles form Earth’s surface • If gas bubbles escape • => effusive eruption • (lava flows) • If gas bubbles can’t escape • => explosive eruption • (pyroclastics) Magma forms inside Earth

  18. Lascar (1993)

  19. Pompei, Italy (76 A.D.)

  20. Mauna Kea Haleakala

  21. COMPARISON OF VOLCANO SIZES Mauna Loa 4170 m above sea level 9100 m above ocean floor MT. FUJI 3777 m above sea level MT. ST. Helens (after 1980 eruption) 2554 m above sea level SEA LEVEL OCEAN FLOOR (from a diagram at the Jaggar Museum, Hawai‘i Volcanoes National Park)

  22. Rift zones are pretty clear from earthquake locations

  23. A “curtain of fire” (actually a curtain of lava) occurs when a dike intersects the volcano’s surface. Most Hawaiian eruptions begin this way. 1971 eruption viewed from the Hawaiian Volcano Observatory, photo by Hawai‘i Volcanoes National Park staff

  24. Solidified dikes exposed by erosion on old Hawaiian volcanoes

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