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THE LIFE AND TIMES OF A HAWAIIAN VOLCANO

THE LIFE AND TIMES OF A HAWAIIAN VOLCANO. -. Scott K. Rowland, University of Hawai‘i at Manoa. O‘ahu consists of two elongate shield volcanoes, Wai‘anae and Ko‘olau. Ko‘olau. Wai‘anae. The “production line” model of Hawaiian volcano evolution. --diagram by Chuck Blay & Robert Siemers.

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THE LIFE AND TIMES OF A HAWAIIAN VOLCANO

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  1. THE LIFE AND TIMES OF A HAWAIIAN VOLCANO - Scott K. Rowland, University of Hawai‘i at Manoa

  2. O‘ahu consists of two elongate shield volcanoes, Wai‘anae and Ko‘olau Ko‘olau Wai‘anae

  3. The “production line” model of Hawaiian volcano evolution...

  4. --diagram by Chuck Blay & Robert Siemers

  5. adapted from Peterson & Moore (1987)

  6. Koko Rift, SE end of Ko‘olau Volcano, O‘ahu

  7. N coast of E. Moloka‘i

  8. actual avalanche scarps obvious cliffs from Moore (1964)

  9. PYROCLASTIC ACTIVITY AND VENT STRUCTURES ON HAWAIIAN VOLCANOES

  10. ERUPTION STYLES AND VENT FORMS

  11. Expanding gas drives a lava fountain. The highest fountains in Hawai‘i are >500 m Technically, the base of the fountain is where the gas becomes 75% by volume, and this is usually 10s to 100s of meters below the vent rim.

  12. - - Pu‘u ‘O‘o scoria cone (in the early 1990s)

  13. - - Kupaianaha lava pond, Kilauea (1986-1992) ~20 m

  14. - Mauna Iki satellitic shield, Kilauea SW rift zone

  15. HYDROMAGMATIC ERUPTIONS (Kapoho, 1960)

  16. Koko Rift rejuvenation-stage volcanism, Ko‘olau volcano, O‘ahu: -most of these eruptions occurred off the shoreline at the time -tuff cones, many nested and/or coalesced, resulted

  17. “surge” deposits, from lateral, turbulent deposition

  18. - Scott K. Rowland, University of Hawai‘i at Manoa HAWAIIAN LAVA FLOWS

  19. - - Lava flows: ‘a‘a and pahoehoe - ‘a‘a: 1. To burn, blaze, glow; fire; staring, as eyes. Fig., angry, fury. Ua ‘a‘a ‘ia au i ke aloha (I burn with love). 2. stony, abounding with ‘a‘a lava. - - - pahoehoe: 1. Smooth, unbroken type of lava. 2. Satin. 3. to drive fish into a net by beating the paddles rhythmically against the canoe. From Hawaiian Dictionary by M.K. Puku‘i & S.H. Elbert

  20. - - ‘a‘a and pahoehoe flows on the north flank of Mauna Loa ~3 m

  21. Wave-cut cliff section, Makapu‘u, O‘ahu

  22. RIFT ZONES AND CALDERAS ON HAWAIIAN VOLCANOES - Scott K. Rowland, University of Hawai‘i at Manoa

  23. Rift zones have the form of broad topographic ridges, and are where flank eruptions occur Topography of Mauna Loa’s SW rift zone (dark flows post-date 1778)

  24. If an eruption is going to occur along a rift zone somewhere, magma has to get there from the magma chamber. It does this as a blade-shaped body of magma called a dike. -Tracking the rock-breaking earthquakes allows geologists to determine that most dikes propagate at 1-2 km/hour. -Harmonic tremor tells geologists that magma is continuing to flow underground. Next time you are near a large water pipe, put your hand on it and you will feel harmonic tremor.

  25. Solidified dikes are exposed by erosion on older Hawaiian volcanoes

  26. - Kilauea caldera: Complex caldera- boundary faults, and Halema‘uma‘u, (H) an intra-caldera pit crater 1954 lava flow H

  27. Ko‘olau rift zone axes and caldera Wai‘anae rift zone axes and caldera Rift zones on O‘ahu are identified most easily by mapping dike swarms.

  28. - ‘Olelo no‘eau involving lava (from M. K. Pukui; compiled by Ululani Makue) - - O ka la ko luna, o ka pahoehoe ko lalo. The sun above, the smooth lava below. Said of a journey in which the traveler suffers because of the heat of the sun above and because of the reflected heat from the lava below (i.e., a difficult trip). - - - - Kīke ke ‘ala, uwe ka mamane. When the boulders clash, the mamane tree weeps. Meaning that when two people fight, those that are dear to them suffer. - PAU

  29. PAU

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