1 / 36

Pyroclastic Activity and Vent Structures on Hawaiian Volcanoes Eruption Styles and Vent Forms

This article explores the various forms of pyroclastic activity and vent structures found on Hawaiian volcanoes. It covers eruption styles, such as high-fountaining and hydromagmatic eruptions, and describes the characteristics of different volcanic deposits. The article also discusses the formation of spatter cones, scoria cones, and lava ponds, providing insights into the volcanic processes at play.

nancydjohnson
Download Presentation

Pyroclastic Activity and Vent Structures on Hawaiian Volcanoes Eruption Styles and Vent Forms

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. - Scott K. Rowland, University of Hawai‘i at Manoa PYROCLASTIC ACTIVITY AND VENT STRUCTURES ON HAWAIIAN VOLCANOES

  2. ERUPTION STYLES AND VENT FORMS

  3. The intersection of a dike with the Earth’s surface: a curtain of “fire” (actually lava) 1971 eruption viewed from the Hawaiian Volcano Observatory, photo by Hawai‘i Volcanoes National Park staff

  4. 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.

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

  6. Scoria cones on the lower south flank of Mauna Kea

  7. Typical high-fountaining pyroclasts: reticulite, scoria, Pele’s tears, and Pele’s hair ~2 cm

  8. Crude layering in a typical high-fountaining deposit

  9. Pele’s hair - produced in high fountains and skylights

  10. - - Blanket of scoria downwind from Pu‘u ‘O‘o

  11. Crude bedding and large bombs in a quarried scoria cone ~2 m

  12. - Cow dung bomb, Kilauea Iki (1959) pyroclastic deposit

  13. Large spindle bomb, East Maui Volcano, SW rift zone

  14. low fountaining, spatter cones, and spatter ramparts (from Volcanoes in the Sea)

  15. Spatter is fluid when it lands ~20 cm

  16. - - ~2 m-wide spatter cone, flank of Pu‘u ‘O‘o scoria cone behind

  17. A line of spatter cones forms a spatter rampart photo by P. Mouginis-Mark

  18. Satellitic shields, from eruptions with ~no pyroclastic activity photo by P. Mouginis-Mark

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

  20. - - - Kupaianaha lava pond and shield, with Pu‘u ‘O‘o scoria cone in the background

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

  22. HYDROMAGMATIC ERUPTIONS (Kapoho, 1960)

  23. May 1924 phreatic eruption, Halema‘uma‘u view from Volcano House hotel, photo by Tai Sing Loo

  24. 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

  25. Molokini Islet, post-shield alkalic series, E. Maui Volcano from Volcanoes in the Sea (Macdonald et al. 1983)

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

  27. Accretionary lapilli: liquid water in the eruption cloud

  28. If you find footprints, do not do this ! They are fragile.

  29. - - Keanakako‘i hydromagmatic ash, SW of Kilauea caldera 1971 lava

  30. - - Keanakako‘i hydromagmatic ash, SW of Kilauea caldera

  31. - Keanakako‘i tephra exposed in upper SW rift zone fractures photo by P. Mouginis-Mark

  32. PAU

More Related