Tuscaloosa Seamount

The Tuscaloosa Seamount is an undersea mountain in the Hawaiian archipelago. It is about northeast of the island Oʻahu.
Tuscaloosa Seamount is composed of volcanic rock, but in contrast to the overwhelming majority of seamounts, it is not a submarine volcano. It is a huge block of rocks that broke off about two million years ago at the Nuʻuanu submarine landslide when the volcano Koʻolau collapsed.
The Tuscaloosa Seamount is long and wide. Its shallow summit rises across the sea bottom but is below sea level.