4D Micro-Piston Motion of Halemaumau Lava Lake Surface Measured with Ground-Based Tripod LiDAR, Kilauea, Hawaii
Abstract
We measured decimeter-scale oscillations in the elevation of the Halemaumau lava lake (HLL) surface at Kilauea Volcano, Hawaii, during a sequence of ground-based Tripod-LiDAR (T-LiDAR) laser scans September 13-14, 2012. Geodetically measuring elevational changes of a dynamic lava lake surface has inherent risks and technical challenges, including the ability to see the lake surface through the volcanic gases. We successfully penetrated most of the dense volcanic gases from the rim of the HLL using the Optech LR laser scanner 1-micron (1064 nm) laser (a wavelength that is not attenuated by water) to measure elevation changes of the surface of the active lava lake 164 meters below the scanner. We found that the average elevation of the entire lava lake surface oscillated with an average 10-cm amplitude across the HLL with increased amplitude (2-3 times larger) proximal to the downwelling portion of the lake. A temporal power-spectrum analysis of the T-LiDAR point cloud resolved an 8.4-second primary oscillation frequency with secondary frequencies at 3.3-second intervals from the primary (1.8, 5.1, 8.4, 11.7 seconds). Preliminary analysis of the seismic spectra shows a peak in the seismic signal at 7.8 seconds (0.13 hz) for the same time period. Qualitative assessment of time-lapse video of the lava lake surface visually confirms that the lava lake rises and falls about every 8 seconds with superimposed smaller-amplitude elevation changes approximately every 3 seconds. We suggest the term micro-pistoning to distinguish this behavior from the larger-scale gas pistoning events at Kilauea that take place over several minutes (Patrick, M. et al, Bull Volcanol, V73(9)pp 1179-1186, 2011).
- Publication:
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AGU Fall Meeting Abstracts
- Pub Date:
- December 2013
- Bibcode:
- 2013AGUFM.V53F..07B
- Keywords:
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- 8414 VOLCANOLOGY Eruption mechanisms and flow emplacement;
- 8494 VOLCANOLOGY Instruments and techniques;
- 1207 GEODESY AND GRAVITY Transient deformation