HR: 0800h
AN: V21A-0380    [Abstracts]
TI: Generation of Hummocky Flow Morphology Revealed through Ground-based LiDAR Measurements of Actively Inflating Pahoehoe Lavas
AU: * Anderson, S W
EM: steven.anderson@unco.edu
AF: MAST Institute, The University of Northern Colorado, Greeley, CO 80639, United States
AU: Finnegan, D C
EM: david.finnegan@erdc.usace.army.mil
AF: Cold Regions Research and Engineering Laboratory (CRREL), 72 Lyme Road, Hanover, NH 03755-1290, United States
AU: Byrnes, J M
EM: jeffrey.byrnes@okstate.edu
AF: Boone Pickens School of Geology, Oklahoma State University, 413 Noble Research Center, Stillwater, OK 74078-3031, United States
AU: Nicoll, K
EM: kathleen.nicoll@gmail.com
AF: University of Utah, 260 South Central Campus Dive, Room 270, Salt Lake City, UT 84112- 9155, United States
AB: Although the extrusion of pahoehoe lava flows is one of the most dominant planetary surface-forming processes in the solar system, emplacement models remain controversial, and affect our ability to understand the implications of continental effusive eruptions. To study the detailed growth patterns of an actively inflating hummocky pahoehoe field in Hawaii, we used a Riegl LMSZ420i ground-based light detection and ranging (LiDAR) system that captures topographic data at unprecedented resolutions and speed, and co-registers the x, y and z coordinates with the RGB values of true color high-resolution (12 megapixel) photographs from an externally-mounted camera. Over a 3-day period (February 21-23, 2007) we acquired 4 surveys of surface topography over a ~200 x 200 m area within the Pu'u O'o flow field that contained actively inflating pahoehoe flows emplaced over older, hummocky pahoehoe lavas. Total scan times ranged from 6 to 19 minutes, with topographic points collected at a 0.05-0.08 degree spacing. Each scan obtained between 1.6 and 5.1 million x, y, and z data points. We acquired topographic data at a rate of 12,000 points/second, permitting repeatable digital elevation model (DEM) generation with 5mm accuracy. We differenced successive DEMs generated from our topographic data to determine the magnitude and patterns of growth. We documented uneven rates of inflation over the area, ranging from less than 0.5 m to 3.9 m, with several tumuli forming over the 3-day time period. These results are the first detailed measurements that help us constrain the movement of lava between upper and lower flow crusts.
DE: 8425 Effusive volcanism
DE: 8429 Lava rheology and morphology
SC: Volcanology, Geochemistry, Petrology [V]
MN: 2007 Fall Meeting