Encyclopedia of Planetary Landforms

2015 Edition
| Editors: Henrik Hargitai, Ákos Kereszturi

Steep-Sided Dome (Io)

  • Henrik Hargitai
Reference work entry
DOI: https://doi.org/10.1007/978-1-4614-3134-3_544


Circular, relatively flat mesa with a central depression and basal scarp.



 Dome (Io); Discoid shield; Unusual shield volcano (Schaber 1980)


The more pristine dome (Inachus) is ∼150 km wide and ∼1.5 km high (Schenk et al. 2001, 2004) with a central pit 2.5–3 km deep (Wilson and Schenk 2002).


Possible shield volcano (Wilson and Schenk 2002) or volcanic dome (Williams et al. 2011).


Formation models (Schenk et al. 2004):
  1. (1)

    High viscosity flows.

  2. (2)

    Erosional remnants of armored circular, radially emplaced lava flows or ash deposits that prevented sublimation or devolatilizing of the underlying material.


Prominent Examples

Inachus and Apis Tholi (Fig. 1).
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  1. Schaber GG (1980) The surface of Io: geologic units, morphology, and tectonics. Icarus 43:302–333CrossRefGoogle Scholar
  2. Schenk PM, Hargitai H, Wilson R, McEwen A, Thomas P (2001) The mountains of Io: global and geological perspectives from Voyager and Galileo. J Geophys Res 106:33201–33222CrossRefGoogle Scholar
  3. Schenk PM, Wilson RR, Davies AG (2004) Shield volcano topography and the rheology of lava flows on Io. Icarus 169:98–110CrossRefGoogle Scholar
  4. Turtle EP, Keszthelyi LP, McEwen AS et al (2004) The final Galileo SSI observations of Io: orbits G28-I33. Icarus 169:3–28CrossRefGoogle Scholar
  5. Williams DA, Keszthelyi LP, Crown DA, Yff JA, Jaeger WL, Schenk PM, Geissler PE, Becker TL (2011) Geologic map of Io. U.S. geological survey scientific investigations map 3168, scale 1:15,000,000Google Scholar
  6. Wilson RR, Schenk PM (2002) From Tohil to Inachus: an Ionian topography progress report. Lunar Planet Sci XXXIII, abstract 1995, HoustonGoogle Scholar

Copyright information

© Springer Science+Business Media New York 2015

Authors and Affiliations

  1. 1.NASA Ames Research Center/NPPMoffett FieldUSA