Slide set compiled by Pete Mouginis-Mark, University of Hawaii
Several of the volcanoes studied by Pete Mouginis-Mark and Scott Rowland are basaltic shields.
Pete and Scott live in Hawaii, so they frequently visit Kilauea and Mauna Loa volcanoes, but they
have also done field work on Fernandina Island in the Galapagos Islands, and they have conducted
remote sensing studies of Karthala volcano (Grand Comores Islands) and Erta Ale (Ethiopia).
As part of his graduate studies, Pete also visited Piton de la Fournaise on Reunion Island in
the Indian Ocean. This work was primarily done to study the large scale geomorphology of the
volcano as an analog to the giant shield volcanoes on the planet Mars, but it also gave a fine
opportunity to document some of the interesting volcanic landforms for subsequent comparison with
Hawaii and the Galapagos. This selection of photos is mainly from Pete's collection from his
visit to Reunion Island in June, 1975.
Our analyses of Piton de la Fournaise are likely to start again with the second flight of the
Space Shuttle Imaging Radar (SIR-C/X-SAR). The volcano is one of the targets for the radar. The
science objective is to map the distribution of pahoehoe and a'a as a way of remotely
determining spatial variations in the effusion rate of the volcano. Watch the EOS Volcanology Web
Pages for results of this SIR-C/X-SAR mission which are coming soon or check out the results
posted by the NASA/JPL SIR-C/X-SAR server!
We hope that you find these images to be interesting. There are many more that have not been
placed on line, so if you have specific questions about what other parts of the island were
photographed (now almost 20 years ago!), please contact Pete. Perhaps this
"historic" data set will help other volcanologists assess the changes that have
taken place on the volcano over the last two decades.
SLIDE #3: SIR-C (1.35Mb
1091 x 1409 JPEG file) (or 377K 490 x 634 GIF file)
In April and October 1994, the Space Shuttle Radar (SIR-C/X-SAR) collected radar images of
many volcanoes around the world. Reunion Island, and Piton de la Fournaise volcano in particular,
was one of the many targets. Here we see a mosaic of "quick-look" L-band (24 cm
wavelength) SIR-C data of the whole island. This is a mosaic of three data takes: DT 146.60 from
the first flight (SRL-1) at left, DT 146.60 from the second flight (SRL-2) in the center, and
SRL-2 DT 98.50 at right. These quick-look data have a spatial resolution of 100 m/pixel. Once they
are processed to full resolution, they will have a resolution of 25 m/pixel, and will be available
in several wavelength/polarization combinations. The look direction in each scene is from the west
(left). Compare this image to Slide #2.
SLIDE #4: SIR-C (618K 750
x 600 JPEG file) (or 364K 750 x 600 GIF file)
Processing of the full resolution SIR-C data for Reunion Island was initiated in June 1995,
and here we show the first image, which was obtained as Data Take 98.5. It shows the southeastern
part of the island, including the active volcano Piton de la Fournaise. The colors in the image
are produced by displaying the L-band HH data in red, L-band HV data in green, and C-band HV data
in blue. Compare this image with Slide #5 to see how the radar has picked out the structure of the
volcano -- and the fact that it is much easier to identifiy the lava flows from the SPOT image.
During the last four days of the second SIR-C mission, the Shuttle flew in 1-day exact-repeat
orbits so that radar interferometry experiments could be conducted. Fortunately, Piton de la
Fournaise was one of the targets imaged (twice) in this mode, thereby enabling a digital
topographic model to be derived from the radar phase data. Work on producing the DEM is currently
underway -- watch this Web page for the results of our efforts!
SLIDE #5 (275K): Overview
This is a SPOT panchromatic image of Piton de la Fournaise that was taken in 1991. The
features identified by red arrows are shown in more detail in the following images.
SLIDE #6 (117K): Summit
This is an oblique air view of the main summit of the active cone. The complete crater seen
here is Crater Bory, which is about 300 meters in diameter. In the background, two sets of caldera
walls can be seen. The summit fissures shown in Slide #14 are located at the lower left of this
SLIDE #7 (225K): Southern Rim
This air view was taken from above the northern rim of Crater Brulant, which is the larger of
the two craters at the summit of the volcano. The southern wall of Brulant is in the middle of
this image, and beyond this can be seen the southern caldera wall. The two cinder cones on the
floor of the caldera were formed in 1963 (the smaller one towards the bottom of the image) and
SLIDE #8 (271K): Crater Rim
This is an almost vertical view looking down at the eastern rim of Crater Brulant and the 1963
(right) and 1964 cinder cones. These cones are about 12 - 15 meters high.
SLIDE #10 (285K): Cinder Cones
There are dozens of fine examples of cinder cones on the flanks of the main cone of Piton de
la Fournaise. Some of these cones are aligned along radial fissures, while others (Slide #11) are
isolated cones. Notice the fine lava channels at the lower center of this image.
SLIDE #11 (304K): 1972 Cone
This is an air view of a cinder cone that formed in 1972. Two separate lava flows originated
from the breach in the side of the cone that faces north.
SLIDE #12 (238K): Crater Floor
This is a ground photograph of the floor of Crater Brulant, standing at the edge of Crater
Bory. The lava flows in the foreground formed in 1955. The two cones towards the far wall are the
1963 (left) and 1964 cones seen in Slide #8.
SLIDE #13 (255K): Western Flank
Standing on the caldera wall, one can get a fine view of the recent a'a flows on the
western flank. Notice that most of these flows originate from a circumferential fissure close to
the summit of the cone. This fissure is shown in more detail in Slide #14.
SLIDE #14 (271K): Summit Fissures
This is a telephoto view of the circumferential fissure that fed the lava flows on the western
flank (Slide #13). This is the same set of fissures seen from the air in Slide #6.