What to know about Hawaii's Mauna Loa volcano

Mauna Loa is one of five volcanoes that together make up the Big Island of Hawaii, which is the southernmost island in the Hawaiian archipelago.

It's not the tallest but it's the largest and makes up about half of the island's land mass.

The ground is shaking and swelling at Mauna Loa, the largest active volcano in the world, indicating that it could erupt.

Scientists say they don't expect that to happen right away but officials on the Big Island of Hawaii are telling residents to be prepared in case it does erupt soon. Mauna Loa last erupted 38 years ago.