A geologic evaluation of proposed lava diversion barriers for the NOAA Mauna Loa Observatory, Mauna Loa Volcano, Hawaii

Lava flow diversion barriers should protect the Mauna Loa Observatory from flows of reasonable magnitude if properly constructed. The a'a flow upon which the observatory is constructed represents a flow of reasonable magnitude.

Proper construction of the barriers includes obtaining riprap from a zone exterior to the proposed V-shaped barrier so as to produce an exterior relief near 9.2 m for most of the barrier, construction of a channel about 8 m deep and 40 m wide along the east part of the barrier, and proper positioning of an isolated initiating barrier.

Calculations suggest that the barriers should be able to handle peak volume flow rates near 800 m/s and possibly larger ones. Peak volume flow rates for the a'a flow upon which the observatory is constructed are estimated.