Thermal overlay of distal part of flow field

This map overlays a georegistered mosaic of thermal images collected during a helicopter overflight of the distal part of Kīlauea's active East Rift Zone lava flow on January 6 at about 11:30 AM. The perimeter of the flow at that time is outlined in yellow. The base image is a satellite image acquired in March 2014 (provided by Digital Globe).

Temperature in the thermal image is displayed as gray-scale values, with the brightest pixels indicating the hottest areas (white shows active breakouts). During the overflight, the two most active areas were the widespread area of breakouts just upslope from the stalled flow behind the Pahoa Marketplace and the front of the flow lobe farther upslope advancing slowly to the north-northeast.

The blue lines show steepest-descent paths calculated from a 1983 digital elevation model (DEM; for calculation details, see http://pubs.usgs.gov/of/2007/1264/). Steepest-descent path analysis is based on the assumption that the DEM perfectly represents the earth's surface. DEMs, however, are not perfect, so the blue lines on this map can be used to infer only approximate flow paths.