Extrusive volcanism formed the Hawaiian Islands, study determines

Oct 07, 2013
Mānoa: Extrusive volcanism formed the Hawaiian Islands, study determines
3-D view of topography & seafloor relief of Hawaiian Islands; colors show residual gravity anomaly.

(Phys.org) —A recent study by researchers at the University of Hawaiʻi at Mānoa School of Ocean and Earth Science and Technology (SOEST) and the University of Rhode Island (URI) changes the understanding of how the Hawaiian Islands formed. Scientists have determined that it is the eruptions of lava on the surface, extrusion, which grow Hawaiian volcanoes, rather than internal emplacement of magma, as was previously thought.

Before this work, most scientists thought that Hawaiian volcanoes grew primarily internally – by intruding into rock and solidifying before it reaches the surface. While this type of growth does occur, along Kilauea's East Rift Zone (ERZ), for example, it does not appear to be representative of the overall history of how the Hawaiian Islands formed. Previous estimates of the internal-to-extrusive ratios (internally emplaced magma versus extrusive lava flow) were based on observations over a very short time frame, in the geologic sense.

Ashton Flinders (M.S. from UHM), lead author and graduate student at URI, and colleagues compiled historical land-based gravity surveys with more recent surveys on the Big Island of Hawaii (in partnership with Jim Kauhikaua of the U.S. Geological Survey – Hawai?i Volcano Observatory) and Kaua?i, along with marine surveys from the National Geophysical Data Center and from the UH R/V Kilo Moana. These types of data sets allow scientists to infer processes that have taken place over longer time periods.

"The discrepancy we see between our estimate and these past estimates emphasizes that the short-term processes we currently see in Hawai?i (which tend to be more intrusive) do not represent the predominant character of their volcanic activity," said Flinders.

"This could imply that over the long-term, Kilauea's ERZ will see less seismic activity and more eruptive activity that previously thought. The 3-decade-old eruption along Kilauea's ERZ could last for many, many more decades to come," said Dr. Garrett Ito, Professor of Geology and Geophysics at UHM and co-author.

"I think one of the more interesting possible implications is how the intrusive-to-extrusive ratio impacts the stability of the volcano's flank. Collapses occur over a range of scales from as large as the whole flank of a volcano, to bench collapses on the south coast of Big Island, to small rock falls," said Flinders. Intrusive magma is more dense and structurally stronger than lava flows. "If the bulk of the are made from these weak extrusive flows then this would account for some of the collapses that have been documented, but this is mainly just speculation as of now."

The authors hope this new density model can be used as a starting point for further crustal studies in the Hawaiian Islands.

Explore further: Hawaiian Islands formed through extrusive volcanic activity

More information: Flinders, A. et al. Intrusive dike complexes, cumulate cores, and the extrusive growth of Hawaiian volcanoes, Geophysical Research Letters, Volume 40, Issue 13, pages 3367–3373, 16 July 2013. DOI: 10.1002/grl.50633

Related Stories

Hawaiian Islands formed through extrusive volcanic activity

Sep 03, 2013

Scientists generally believe that the Hawaiian Islands formed primarily through endogenous growth, or intrusion, in which hot magma intrudes into a rock and then solidifies before it reaches the surface. However, a new study ...

Tracking a hot spot

May 17, 2007

Using a state-of-the-art satellite imagery technique, researchers are able to more precisely predict volcanic activity, bringing them steps closer to understanding where an eruption may occur. A new research study, titled ...

Recommended for you

Clean air: Fewer sources for self-cleaning

12 hours ago

Up to now, HONO, also known as nitrous acid, was considered one of the most important sources of hydroxyl radicals (OH), which are regarded as the detergent of the atmosphere, allowing the air to clean itself. ...

There's something ancient in the icebox

12 hours ago

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

Image: Grand Canyon geology lessons on view

19 hours ago

The Grand Canyon in northern Arizona is a favorite for astronauts shooting photos from the International Space Station, as well as one of the best-known tourist attractions in the world. The steep walls of ...

First radar vision for Copernicus

19 hours ago

Launched on 3 April, ESA's Sentinel-1A satellite has already delivered its first radar images of Earth. They offer a tantalising glimpse of the kind of operational imagery that this new mission will provide ...

User comments : 0

More news stories

There's something ancient in the icebox

Glaciers are commonly thought to work like a belt sander. As they move over the land they scrape off everything—vegetation, soil, and even the top layer of bedrock. So scientists were greatly surprised ...

China says massive area of its soil polluted

A huge area of China's soil covering more than twice the size of Spain is estimated to be polluted, the government said Thursday, announcing findings of a survey previously kept secret.

Clean air: Fewer sources for self-cleaning

Up to now, HONO, also known as nitrous acid, was considered one of the most important sources of hydroxyl radicals (OH), which are regarded as the detergent of the atmosphere, allowing the air to clean itself. ...

Better thermal-imaging lens from waste sulfur

Sulfur left over from refining fossil fuels can be transformed into cheap, lightweight, plastic lenses for infrared devices, including night-vision goggles, a University of Arizona-led international team ...

Hackathon team's GoogolPlex gives Siri extra powers

(Phys.org) —Four freshmen at the University of Pennsylvania have taken Apple's personal assistant Siri to behave as a graduate-level executive assistant which, when asked, is capable of adjusting the temperature ...