[meteorite-list] Mars Express: Olympus Mons - The Caldera in Close-Up

From: Ron Baalke <baalke_at_meteoritecentral.com>
Date: Thu Apr 22 10:31:22 2004
Message-ID: <200402121826.KAA00494_at_zagami.jpl.nasa.gov>

http://www.esa.int/export/SPECIALS/Mars_Express/SEM9BA1PGQD_0.html

Olympus Mons - the caldera in close-up

Complex caldera of Olympus Mons - Mars Express
 
11 February 2004

View from overhead of the complex caldera (summit crater) at the summit of
Olympus Mons on Mars, the highest volcano in our Solar System.
 
Olympus Mons has an average elevation of 22 km and the caldera has a depth of
about 3 km. This is the first high-resolution colour image of the complete caldera
of Olympus Mons.

The image was taken from a height of 273 km during orbit 37 by the High
Resolution Stereo Camera (HRSC) on ESA?s Mars Express on 21 January
2004. The view is centred at 18.3°N and 227°E. The image is about 102 km
across with a resolution of 12 m per pixel. South is at the top.
 
This complementary 3D view shows the Olympus Mons volcano in its
entirety, to put the caldera images in context. It has been derived from the
Mars Orbiter Laser Altimeter (MOLA) topographic data
superimposed with the Mars Orbiter Camera (MOC) wide-angle image
mosaic.
 
Detail of the southern part of the caldera in perspective - Mars Express
 
This perspective view shows the southern part of the caldera. The image has
been calculated from the digital elevation model derived from the stereo channels
and combined with the nadir- and colour-channels of the Mars Express HRSC.

The scene reveals tongue-shaped mass-movement features in 3D on the
southern wall. The striations are tectonic faults. After lava production has
ceased the caldera collapsed over the emptied magma chamber. Through the
collapse the surface suffers from extension and so extensional fractures are
formed. The elevation level on which these fractures can be observed represents
the event of the oldest caldera collapse. Later lava production has produced new
caldera collapses at different locations (the other circular depressions), they
partly destroyed the circular fracture pattern of the oldest one.

The data has been retrieved from a height of 273 km during orbit 37 on 21
January 2004. The view is centred at 18.3°N and 227°E. The image is about 40
km across. The vertical exaggeration is 1.8. South is up to allow the
mass-movement features to be seen.
 
This perspective view has been calculated from the digital elevation
model derived from the stereo channels and combined with the
nadir- and colour- channels of the HRSC.

The data has been retrieved from a height of 273 km in orbit 37 on 21
January 2004. The view is centred at 18.3°N and 227°E. The image is 102
km across and has a resolution of 12 m per pixel. The vertical exaggeration
is 1.8. South is up.
 
Received on Thu 12 Feb 2004 01:26:58 PM PST