Chevrel, M.O.

Hauber, Ernst

Jaumann, Ralf

Le Deit, Laetitia

Neukum, Gerhard

Platz, Thomas

Preusker, Frank

Trauthan, Frank

Institute of Transport Research:Publications

Preliminary Results on Lava Flow Morphologies and Vent Structures: An Example from the Western Volcanic Zone, Iceland

Geophysical Research AbstractsVol. 13, EGU2011-12975, 2011EGU General Assembly 2011© Author(s) 2011Preliminary results on lava flow morphology and vent structures: anexample from the Western Volcanic Zone, IcelandThomas Platz (1), Ernst Hauber (2), Oryaelle Chevrel (3), Laetitia Le Deit (2), Frank Trauthan (2), FrankPreusker (2), Ralf Jaumann (2), and Gerhard Neukum (1)(1) Freie Universität Berlin, Institute of Geological Sciences, Planetary Sciences and Remote Sensing, Berlin, Germany(thomas.platz@fu-berlin.de), (2) German Aerospace Centre (DLR), Institute of Planetary Research, Rutherfordstr. 2, 12489Berlin, (3) LM University Munich, Department of Earth and Environmental Sciences, Theresienstr. 41, 80333 MunichIceland exhibits a vast diversity of volcanic landforms and products. Due to its location at high latitudes, andhence, sparse vegetation cover along with good accessibility to most volcanically active areas, Iceland has beena prime region for terrestrial analogue studies to understand, in particular, Martian volcanism. In 2006, a flightcampaign was carried out to image parts of the Western Volcanic Zone about 40 km to the east of Reykjavik. TheHRSC-AX camera mounted to an aircraft is basically identical to the HRSC camera onboard Mars Express. In2010, a field campaign was organized to investigate lava flow morphologies, volcanic landforms such as spatterand scoria cones, fissures, and tectonic features. Field activities were primarily focused on two lava flows in thenortheastern part of the Western Volcanic Zone. Mapping and description of lava flow features from proximal todistal reaches were complemented with selected Differential GPS profiles perpendicular to flow direction. Herewe report on our observations of lava flow morphologies in general and on one lava flow in particular which wastraced from vent to its distal front lobe.HRSC-AX data were processed similar to HRSC products. Colour, panchromatic, and digital-terrain-modelmosaics were created with spatial resolutions of 1 m (several panchromatic subsets have up to 25 cm/px). TheDTM has a vertical accuracy of 10 cm and an absolute accuracy of 20 cm. Prior to the field campaign, selectedlava flows were mapped on HRSC-AX imagery in a GIS environment. The extent of mapped lava flows wasverified in the field and where necessary corrected using handheld GPS for positioning.The study area is located between two NE-trending hyaloclastite ridges. Numerous fissures and cones, and onelarge tuya manifest the main sources of lava emission. The area between the two ridges was flooded. As a result,the lava plain is moderately sloping towards Thingvallavatn and Skjaldbreidur. The lava flows consist exclusivelyof pahoehoe lava except at distal lobes and where steep scarps were overridden forming aa lava. Open-channelflows formed predominantly near the vent up to medial reaches. Lava tubes can directly emanate from the ventand extend to medial reaches before turning into sheet-type flows and lobes. Due to the low gradient between theridges, small- and large-scale inflation features and clefts are frequently observed.The examined lava flow originated from a 300 m long fissure which partially developed into two point-sourcedcones to the SE. The NE part of the fissure is rimmed by up to 50 m of scoria and spatter. One cone is madeof a pile of individual lava tubes caused by a dominant effusive style of eruption also indicating its late-stageemplacement. Draining of lava forming the main lava flow occurred to the NE over a c.20 m high cliff, and thelava travelled up to 4.6 km from the fissure. The lava flow developed an open main channel (c.15 m wide and 3m deep) close to the source and subsequently widens further downstream to up to 110 m. Two small lava lobesdeveloped where the main flow changed direction by 90◦. From the base of the cliff below the fissure to the distalfront lobe an elevation difference of 60 m is noted. The transition from open-channel flow to a sheet dominatedflow occurs over 350 m. Within this zone small pressure ridges developed.Detailed morphometric studies will be carried out on selected lava flows based on remotely sensed data andground-based Differential GPS. Hard rock samples at various locations within the flows were collected. Petro-graphic and petrologic analyses and viscosity measurements will be performed to estimate bulk flow rheologies.Laboratory results are then compared to conventional methods to determine lava rheology. The results willbe applied to suitable volcanic lava flows on Mars in order to reliably estimate rheology, and hence, eruptionproperties.

Preliminary results on lava flow morphology and vent structures: an example from the Western Volcanic Zone, Iceland

Preliminary Results on Lava Flow Morphologies and Vent Structures: An Example from the Western Volcanic Zone, Iceland

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Institute of Transport Research:Publications

Institute of Transport Research:Publications