Old lava flow gave
Mauna Loa’s summit
its shape, scientists say

By Rod Thompson
Star-Bulletin

HILO >> Mauna Loa's summit has a cratered shape, thanks to a huge lava flow about 1,400 years ago, the Hawaiian Volcano Observatory says in its weekly Volcano Watch column.

At the top of the 13,679-foot volcano is a large crater, called a caldera, four miles long and a mile and a half wide. The feature, called Mokuaweoweo, contrasts with the pointed summit of 13,796-foot Mauna Kea.

Mauna Loa has a caldera because magma that supported the summit drained away centuries ago, causing a summit collapse, the observatory said.

The drainage came out of the side of the mountain near the current Kulani Prison and created the "immense" Panaewa flow, which covered 66 square miles and ran all the way to the sea.

The lava also shaped Hilo.

Ten miles of coastline from Coconut Island in Hilo Bay to the Shipman Estate seaward of Keaau consists of Panaewa lava.