Klauea is the world's most active volcano, yet we don't know how it formed.
New study reveals magma's birthplace is 90 km below the hotspot.
Previous investigations revealed two shallow magma chambers under Klauea, but they couldn't explain all its lava.
In 2014, seismic waves identified a chamber 11 kilometres (6.8 miles) underground, however the original chamber may be deeper.
Fragments of old volcanic rock recovered from the Big Island's southeast show Klauea was created from a 100-kilometer-deep pyroclastic pool.
The Pacific tectonic plate moved 210,000 to 280,000 years ago, sending a magma plume into the sea.