With reports of high temperatures emanating from the 2018 lava flows on Puna’s partially reconstructed Highway 132, Philip Ong and I were able to conduct an independent survey when construction had a down-day. Using a thermal camera both on the ground and mounted on a drone, we searched for and measured hotspots that have the potential to compromise the application of an asphalt base layer in upcoming phases of construction. While most of the road base is under 140 °F in the full sun (below temperatures that could compromise asphalt), we identified multiple problematic hotspots on the edges of the new road, the hottest measured at 550 °F at the surface and 880 °F inside the cracks with a thermocouple. The hot areas we identified exist within very dense rock which is being ripped out to get the road down to the planned grade. There are also sections of the road which have been built up to grade, effectively bring up the low areas and knocking down the high areas - which can vary by a few dozen feet in elevation.
Due to the construction delays encountered in the lower section of Highway 132 an extension from FHWA has been requested by the County for the initial October 5th deadline. With the temperatures observed by Hawaiian Volcano Observatory (~750°F) and Hawaii Department of Public Works (560°F) in mind and after completing our own survey of the area, the maximum designed temperatures observed well exceed the design specifications for asphalt in some pockets.
The end of the video is a compilation of aerial footage taken during the eruption, and footage one year later during the highway reestablishment project. Footage of the flows credit to USGS-HVO and Hawaii Civil Defense.
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