Free Newsletters - Space News - Defense Alert - Environment Report - Energy Monitor
. Earth Science News .




SHAKE AND BLOW
Extrusive volcanism formed the Hawaiian Islands
by Staff Writers
Honolulu HI (SPX) Oct 09, 2013


This is a 3-D perspective view of the topography of the Hawaiian Islands (gray shaded) and seafloor relief viewed from just south of the Hawaii's Big Island. The colors show residual gravity anomaly, measured on land and along ship tracks: red-cyan representing an excess pull of gravity, blue representing a small deficit in the pull of gravity. Credit: Ashton Flinders, UHM SOEST.

A recent study by researchers at the University of Hawaii - Manoa (UHM) 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 magma 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 - Hawaii Volcano Observatory) and Kauai, 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 Hawaii (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 islands 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.

.


Related Links
University of Hawaii
Bringing Order To A World Of Disasters
When the Earth Quakes
A world of storm and tempest






Comment on this article via your Facebook, Yahoo, AOL, Hotmail login.

Share this article via these popular social media networks
del.icio.usdel.icio.us DiggDigg RedditReddit GoogleGoogle




Memory Foam Mattress Review
Newsletters :: SpaceDaily :: SpaceWar :: TerraDaily :: Energy Daily
XML Feeds :: Space News :: Earth News :: War News :: Solar Energy News





SHAKE AND BLOW
Scientists tag Indonesian volcano as source of 13th century eruption
Cambridge, England (UPI) Oct 1, 2013
Scientists say they've identified an Indonesian volcano responsible for a huge 13th century eruption that may have caused climate cooling and failed harvests. The 1257 eruption was so large it left its chemical signature in the ice of both the arctic and the antarctic, they said. Writing in the PNAS journal, an international team has named the Samalas Volcano on Lombok Island, In ... read more


SHAKE AND BLOW
Smart smoke alarm can speak, warn of smoke, carbon monoxide

European satellites included in test of search-and-rescue system

Indonesia to boost patrols against people smugglers

'Ship in a bottle' detects dangerous vapors

SHAKE AND BLOW
Ultrasound system gives virtual feeling of objects in mid-air

Himawari and Mitsubishi Electric Complete Facilities For Weather Satellite Ops

Disney Research develops algorithm for rendering 3-D tactile features on touch surfaces

World's Largest Solar Sail, Sunjammer, Completes Test

SHAKE AND BLOW
University teams with industry to build deep-sea submersible

Improving water security with blue, green, and gray water

Plastic waste is a hazard for subalpine lakes too

Japan asks WTO to intervene on S.Korean atomic fish ban

SHAKE AND BLOW
Brazil to start work on new Antarctic base next year

US shutdown puts freeze on Antarctic research

Giant channels discovered beneath Antarctic ice shelf

Government shutdown threatens U.S. antarctic research

SHAKE AND BLOW
Google Street View is new arm against alien species

Asia's changing food needs mean export opportunities

No Fukushima radiation effect on bulls

Bt sweet corn can reduce insecticide use

SHAKE AND BLOW
Extrusive volcanism formed the Hawaiian Islands

Industry alarm over worsening Thai floods

How one Transportation Business Survived Hurricane Sandy

Typhoon Fitow kills 10 in east China province

SHAKE AND BLOW
Islamists step up attacks in north Mali

Ethiopia says no plans to withdraw troops from Somalia

'Armed bandits' kill Niger soldier, wound three others in Nigeria: official

Nigeria bombs Boko Haram 'camp' near site of massacre

SHAKE AND BLOW
Council of Europe attacks genetic procedure

Ancient sagas show Vikings more social, less warlike

Einstein's genius put down to 'well-connected' brain halves

Roma families face wholesale expulsion from France




The content herein, unless otherwise known to be public domain, are Copyright 1995-2014 - Space Media Network. AFP, UPI and IANS news wire stories are copyright Agence France-Presse, United Press International and Indo-Asia News Service. ESA Portal Reports are copyright European Space Agency. All NASA sourced material is public domain. Additional copyrights may apply in whole or part to other bona fide parties. Advertising does not imply endorsement,agreement or approval of any opinions, statements or information provided by Space Media Network on any Web page published or hosted by Space Media Network. Privacy Statement