Small-Scale Volcanic Activity on Tharsis
Small-Scale Volcanic Activity on Tharsis
ESP_018969_1950  Science Theme: Volcanic Processes
This image shows detail of a small volcanic complex in the region of Mars called Tharsis.

Tharsis, a high volcanic region thousands of kilometers wide, hosts some of the largest known volcanos in the Solar System. The volcanic crater seen here, however, is only about 1 kilometer (0.6 miles) across. This means that Tharsis was covered with volcanic activity at a wide range of scales. The wavy ridges of material seen here are solidified lava flows.

On some flows, a set of narrow parallel ridges, or levees, illustrate how the flowing lava created its own path as it flowed along. Measuring the height and width of these levees and the flows themselves can yield information on the lava's rheology, or how it flowed and moved. In turn, rheology depends on the composition of the lava, among other factors. Knowing how lava moved across the surface of Mars and what it was made of can help scientists determine how similar Mars volcanic processes were to those on Earth.

In order to facilitate vertical measurements from images, such as the height of these levees, the MRO spacecraft has the ability to roll to its side, allowing the HiRISE camera to take images of a spot on the surface, like these lava flows, from two different angles (on two different orbits). From these two images a stereo image and digital terrain model of topography can be created, much as the separation between your two eyes allows you to view objects in three dimensions. (The stereo pair for this image consists of this image and ESP_018468_1950.)

One factor that will complicate the study of these lava flows is that they are quite old, and thus have been damaged and covered by impact cratering and deposition and removal of material by the wind.

Written by: Patrick Russell  (15 September 2010)

This is a stereo pair with ESP_018468_1950.
Acquisition date
13 August 2010

Local Mars time

Latitude (centered)

Longitude (East)

Spacecraft altitude
274.6 km (170.7 miles)

Original image scale range
28.5 cm/pixel (with 1 x 1 binning) so objects ~86 cm across are resolved

Map projected scale
25 cm/pixel and North is up

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Emission angle

Phase angle

Solar incidence angle
48°, with the Sun about 42° above the horizon

Solar longitude
132.4°, Northern Summer

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North azimuth:  97°
Sub-solar azimuth:  19.2°
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All of the images produced by HiRISE and accessible on this site are within the public domain: there are no restrictions on their usage by anyone in the public, including news or science organizations. We do ask for a credit line where possible:

NASA’s Jet Propulsion Laboratory, a division of the California Institute of Technology in Pasadena, Calif., manages the Mars Reconnaissance Orbiter for NASA’s Science Mission Directorate, Washington. The HiRISE camera was built by Ball Aerospace and Technology Corporation and is operated by the University of Arizona.