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SURFACE FEATURES ON HAWAIIAN VOLCANOES

GG 460 Final Project Intro. SURFACE FEATURES ON HAWAIIAN VOLCANOES. For proper display, install the Technical font (TECHNCLN.TTF), in this same directory. -. -. ‘a‘a and pahoehoe flows on the north flank of Mauna Loa. ~3 m. -. ‘a‘a flows.

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SURFACE FEATURES ON HAWAIIAN VOLCANOES

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  1. GG 460 Final Project Intro. SURFACE FEATURES ON HAWAIIAN VOLCANOES For proper display, install the Technical font (TECHNCLN.TTF), in this same directory

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

  3. - ‘a‘a flows

  4. The top surface is relatively small, spiny clinkers

  5. Air photo of the distal end of the 1942 Mauna Loa flow

  6. - pahoehoe flows

  7. - Flow field of pahoehoe “toes” (individual flow units) ~0.5 m

  8. - Shelly pahoehoe: formed by coalescence and expansion of gas bubbles

  9. Comparison of s-type and p-type pahoehoe - Spongy pahoehoe (s-type) Pipe-vesicle-bearing pahoehoe (p-type) -

  10. - Stretched vesicle walls on the skin of s-type pahoehoe ~10 cm

  11. - fresh p-type (p) and s-type (s) pahoehoe s p p p s s

  12. An ochre-colored secondary mineral (some sort of clay?) commonly forms on non-vesicular glassy basalt surfaces (“blue-glassy” pahoehoe doesn’t stay blue for ever) -

  13. Side view into an active lava tube

  14. Tumulus on 1859 Mauna Loa flow, on the coastal flat George Walker for scale

  15. ERUPTION STYLES AND VENT FORMS

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

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

  18. Crude layering in a typical high-fountaining deposit

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

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

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

  22. Uplift due to lava intrusion within a satellitic shield surface ~10 m

  23. The rubbly margin of one of these intrusion features

  24. Small toothpaste lava lobe issuing out from the rubble ~1 m

  25. HYDROMAGMATIC ERUPTIONS (Kapoho, 1960)

  26. Accretionary lapilli: liquid water in the eruption cloud

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

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

  29. Windblown sand (low albedo, high temperature, smooth) Vegatation (high in near-IR, low temperature, rough)

  30. Fissures dark in vis (shadowed) Bright in SAR if viewed perpendicular to fissure

  31. Weathering processes on Hawaiian lava surfaces -color (black/gray to red/brown/tan) due to Fe oxidation -accretion of SiO2-rich coatings -devitrification of glassy pahoehoe -spalling of vesicular crusts -

  32. Reflectance changes in wavelengths similar to Landsat bands for some Mauna Loa ‘a‘a flows (Abrams et al. 1991) - “redness” increases with age Fe++ Fe+++ in olivine, pyroxene, magnetite causes the reflectance decrease in shortest s development of clay minerals causes decrease in longer s

  33. Thermal Infrared Mapping Spectrometer (TIMS): 6 bands from 8-12 m - - Fresh Pu‘u ‘O‘o pahoehoe -this broad peak is a result of disordered bonds in the glassy surface, 4  5 > 6 > 3 >> 2 > 1 - - - Week-old Pu‘u ‘O‘o pahoehoe - B = stretching vibrations of Si2O5 sheet-like units, C decreases due to devitrifi- cation 5 > 6 > 4 > 3 >> 2 > 1

  34. - 101 year-old Mauna Loa pahoehoe - - - Week-old Pu‘u ‘O‘o pahoehoe B = stretching vibrations of Si2O5 sheet-like units, C decreases due to devitrifi- cation 5 > 6 > 4 > 3 >> 2 > 1 B = stretching vibrations of Si2O5 sheet-like units, C decreases due to devitrifi- cation, A, D = SiO and AlO vibrations in surface crusts, D = AlO vibrations: 3 > 2  4 > 1 > 5 > 6

  35. REFERENCES FOR BASALT SPECTROSCOPY Abrams et al. (1991) “Combined use of visible, reflected infrared, and thermal infrared images for mapping Hawaiian lava flows” JGR 96 no. B1: pp. 475-484 Crisp et al. (1990) “Thermal infrared character of Hawaiian basaltic glasses” JGR 95 no. B13: pp. 21,657-21,669 Kahle et al. (1988) “Relative dating of Hawaiian lava flows using multispectral thermal infrared images: a new tool for geologic mapping of young volcanic terranes” JGR 93 no. B12: pp. 15,239-15,251

  36. PAU

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