Mauna Loa, also known as West Molokai Volcano, is the name given to an extinct shield volcano

Shield volcano

A shield volcano is a type of volcano usually built almost entirely of fluid lava flows. They are named for their large size and low profile, resembling a warrior's shield. This is caused by the highly fluid lava they erupt, which travels farther than lava erupted from more explosive volcanoes...

 comprising the western half of Molokai

Molokai

Molokai or Molokai is an island in the Hawaiian archipelago. It is 38 by 10 miles in size with a land area of , making it the fifth largest of the main Hawaiian Islands and the 27th largest island in the United States. It lies east of Oahu across the 25-mile wide Kaiwi Channel and north of...

 in the U.S. state

U.S. state

A U.S. state is any one of the 50 federated states of the United States of America that share sovereignty with the federal government. Because of this shared sovereignty, an American is a citizen both of the federal entity and of his or her state of domicile. Four states use the official title of...

 of Hawaii

Hawaii

Hawaii is the newest of the 50 U.S. states , and is the only U.S. state made up entirely of islands. It is the northernmost island group in Polynesia, occupying most of an archipelago in the central Pacific Ocean, southwest of the continental United States, southeast of Japan, and northeast of...

. It was constructed in two volcanic phases. The first constructed the broad tholeiitic shield volcano of Mauna Loa that ended 1.89 million years ago and the second volcanic phase produced postshield alkalic volcanics 1.76 million years ago. Mauna Loa overlaps the western flank of Wailau

Wailau

Wailau, also known as East Molokai Volcano, is an extinct shield volcano comprising the eastern two-thirds of the island of Molokai in the U.S. state of Hawaii.-Description:...

, a much larger shield volcano comprising two-thirds of Molokai.