AGU: Geophysical Research Letters

 

Editors' Highlight

Monitoring Mount St. Helens

In September 2004, Mount St. Helens experienced a swarm of shallow earthquakes. In the following weeks the crater floor deformed, steam and ash erupted, and lava extruded, accompanied by the formation and uplift of a new lava dome. During this period of unrest, Vaughan et al. (2005) took images of the volcano using the NASA MODIS/ASTER (MASTER) airborne simulator paired with range-finding lidar, allowing the authors to match MASTER observations in the thermal infrared (TIR) range with georeferenced elevation data. In addition, forward looking infrared cameras were deployed to collect ground- and helicopter-based thermal images. These data allowed the authors to view surface temperatures, calculate radiative cooling rates and corresponding radiative power, and observe structural deformation. Spectral analysis determined that the extruding lava was dacitic, and MASTER and lidar data confirmed that the dome grew in areas that experienced elevated temperatures. The authors comment that airborne platforms not only provide higher spatial resolution than satellites but that such platforms can be rapidly deployed to an erupting volcano to monitor hazards as they are created. In addition, they suggest that the combination of MASTER TIR and lidar data can lead to improved visualization and interpretation of an evolving volcanic system.

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