Volcanism as an Active!
Planetary Process on Venus!
M. W.
1
Airey ,
1
Mather ,
1
Pyle ,
T. A.
D. M.
K. L.
3
3
4!
F. W. Taylor , C. F. Wilson , R. C. Ghail
1Dept.
of Earth Sciences, University of Oxford, South Parks Road, Oxford, OX1 3AN, UK., 2Dept. of Physics, University of Oxford, The Denys Wilkinson Building,
Keble Road, Oxford, OX1 3RH, UK., 3Dept. of Atmospheric, Oceanic and Planetary Physics, University of Oxford, Parks Road, Oxford, OX1 3PU, UK., 4Dept. of
Civil and Environmental Engineering, Skempton Building, Imperial College London, South Kensington Campus, London, SW7 2AZ, UK. !
Styles of Volcanism!
Introduction!
Volcano
morphology
and radar
properties!
!
!
Is Venus currently volcanically active?!
!
If so, what styles of volcanism occur on Venus?!
!
How do volcanic processes interact with the geology and climate of Venus?!
!
How has volcanism affected the long-term planetary evolution of Venus?!
!
What will be the role of volcanism in the future evolution of Venus?!
!
Venus offers a unique laboratory with which to investigate the effects of volcanism in a non-Earth type setting and
the evolution of extreme environments on a planetary scale. The project will implement morphological,
compositional, spatial, and temporal comparisons of Venusian volcanoes facilitated by the compilation of a
comprehensive database of such features derived from radar observations. Modelling techniques [1,2] will be
utilised to predict the physical behaviour of subaerial volcanism given these observations, specifically whether or
not buoyant plumes can be generated, and the ways in which they interact with the atmosphere. Further climate
modelling exercises [e.g. 3] exploring a variety of rates, magnitudes, and styles of periodic behaviour of volcanism
will potentially offer insights into the nature of Venusian volcanism and its effects on planetary evolution [4,5].!
Morphological comparisons may be suggestive of eruptive style. By comparison with
terrestrial processes, high aspect ratios and large summit calderas may suggest that
volcanoes have displayed explosive behaviour. !
Mt. Fuji – Earth!
Height 3.8 km!
h/d = 0.08!
Mauna Loa – Earth!
Height 4.1 km!
h/d = 0.02!
~150 km!
~50 km!
Explosive?!
Idunn Mons – Venus!
Height 2.5 km!
h/d = 0.008!
Subaerial
plume models!
Effusive?!
5 km!
Small ‘stratocone’ – Venus!
Height 0.6 km!
h/d = 0.12!
Climate
modelling!
~300 km!
Long-term
planetary
evolution!
Typical Magellan data from
www.mapaplanet.org!
Future work!
1.  Precise location coordinates and radar geometry !
!
2.  Altimeter and parallax elevations!
Idunn Mons - 47°S 215°E!
3.  Morphometric measurements and ratios!
4.  Backscatter coefficient!
Right-look!
Left-look!
5.  RMS slope, RMS height, correlation length!
6.  Emissivity!
7.  Reflectivity!
8.  Dielectric constant!
Emissivity!
Topography!
9.  Density!
10. Temperature and pressure lookup from VIRA!
11. Relative age!
12. Spatial relationships with other geographic features!
!
75 m/px!
75 m/px!
§ 
The database will be expanded to include all
volcanoes ≥20 km in diameter and means
calculated from smaller volcanoes!
§ 
Morphological groupings will be defined based
on eruptive style!
§ 
Systematic temporal and/or spatial trends will
be investigated with which to explore the
history and distribution of volcanism!
§ 
Physical subaerial plume models will be
parameterised to result in the observed
eruptive style of a given volcano and thus
improve constraints on eruptive temperature,
velocity, density, volatile content, and plume
height!
§ 
Further evidence for ongoing volcanism will be
sought in the Venus Express datasets!
§ 
Climate modelling investigations will be
undertaken to investigate how the previous
findings may correlate with a variety of
volcanic scenarios!
§ 
A thorough and considered study of the longterm effects of volcanism on the evolution of
the Venus system!
§ 
This will contribute to our understanding of the
long-term planetary evolution of Venus.!
100 km!
5 km/px!
Data are collected for the edifice itself, its surroundings, and any
interesting features on or around it. The result will be a body of data
from which inferences can be drawn from the relationships between
these parameters as to the eruptive styles and geological evolution of
individual volcanoes and regional scale volcanic provinces.!
Reflectivity!
5 km/px!
Geological
interpretation!
Eruptive
styles of
volcanism!
Compiling a database!
Image measurements and data values collected or calculated:!
!
2
Aplin ,
5 km/px!
Metre-scale slope!
5 km/px!
NASA/JPL Contact:!
scan me!
Acknowledgements!
!
Postgraduate studentship funding from The Science and Technology Facilities Council. Additional funding from The Geological Remote Sensing Group and travel bursary from The Universities Space Research Association.!
!
References!
!
[1] Glaze, L. S. (1999) Transport of SO2 by explosive volcanism on Venus, Journal of Geophysical Research-Planets, 104, 18899-18906, doi:10.1029/1998je000619, [2] Glaze, L. S., Baloga, S. M., and Wimert, J. (2011)
Explosive volcanic eruptions from linear vents on Earth, Venus, and Mars: Comparisons with circular vent eruptions, Journal of Geophysical Research-Planets, 116, doi:10.1029/2010je003577, [3] Bullock, M. A., and
Grinspoon, D. H. (2001) The recent evolution of climate on venus, Icarus, 150, 19-37, doi:10.1006/icar.2000.6570, [4] Taylor, F., and Grinspoon, D. (2009) Climate evolution of Venus, Journal of Geophysical ResearchPlanets, 114, doi:10.1029/2008je003316, [5] Taylor, F. W. (2011) Comparative planetology, climatology and biology of Venus, Earth and Mars, Planetary and Space Science, 59, 889-899, doi:10.1016/j.pss.2010.11.009!
[email protected]!