Mauna Loa on EARTH Magazine

Mauna Loa's mysterious Ninole Hills were once a rift

Tue, 26 Jul 2016 09:57:04 -0400

The Nīnole Hills (orange area) on the southeast flank of Mauna Loa are suggested to be a failed rift (blue dashed line) that migrated toward the current Southwest Rift Zone (yellow dashed line). Credit: U.S. Geological Survey.

Hawaii’s Nīnole Hills, jutting out from Mauna Loa’s southeast flank, are one of the most striking features on the Big Island, though their geologic origins have long been a mystery. A new study looking at gravity anomalies under the hills is revealing that the hills are part of an older rift system that predates the currently active Southwest Rift Zone. The seemingly sudden switch from one rift system to another may provide some clues as to how Mauna Loa grew to be the largest volcano on Earth. “A lot of different ideas have been proposed to explain how the Nīnole Hills were created,” says Jeff Zurek, a geophysicist at Simon Fraser University in Burnaby, British Columbia, and lead author of the new study published in Geophysical Research Letters. It’s been suggested that the hills could be the remnants of an older summit of Mauna Loa, or its predecessor, Mohokea, or that faulting and landslides could have created the unusual topography of the hills, or that they could be from an older, inactive rift system.

Kilauea eruptions could shift from mild to wild

Fri, 29 Aug 2014 11:49:57 -0400

Kilauea is the most active of the five volcanoes that form the Big Island of Hawaii and one of the most continuously active volcanoes in the world. Credit: ©Shutterstock.com/Alexey Kamenskiy.

Hawaii’s Kilauea volcano is famously effusive: Low-viscosity lava oozes out of the main caldera and two active rift zones along the southern shore of the Big Island. But scientists suspect that Kilauea’s eruptions haven’t always been so mild, and a new study is providing further evidence supporting that notion. In the past 2,500 years, at least two cycles of explosive eruptions lasting several centuries each have rocked the island. The switch from effusive back to explosive is likely to occur again, scientists say, but probably not anytime soon.

Living in the shadow of Mauna Loa: A silent summit belies a volcano's forgotten fury

Thu, 07 Aug 2014 10:34:10 -0400

Earth’s largest active volcano is taking a nap. And after 30 years, no one is quite sure when Hawaii’s Mauna Loa will reawaken. Odds are that it will be within the next couple of decades — and that it will be spectacular.

Travels in Geology: Taking in Hawaii's Big Island

Thu, 05 Jan 2012 06:41:58 -0500

The Big Island of Hawaii, with two snow-topped peaks: Mauna Loa, to the south, and Mauna Kea, to the north. NASA Earth Observatory

For a bit of money, visitors to Hawaii can indulge their touristy impulses with a single night of mai tais and luaus. But take on Hawaii’s geologic hallmarks, and you’ll embark on a low-cost safari that will last you all week.