Standing waves in a fast-moving `a`a channel on Mauna Loa Volcano Volcano, Hawai`i. The lava is moving from right to left up and over the waves.

S size="+2">tanding wave

Standing waves in a fast-moving lava flow appear to be stationary relative to the lava that moves over and through them, similar to standing waves in a water stream. In Hawai`i, standing waves as high as 3 m have been observed.