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NSF PR 96-61 - October 18, 1996
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Six-Year Drilling Project to Uncover One Million Years
of Earth History
$10 Million NSF Grant
Scientists will drill as much as a million years into
the geologic history of the Earth to study the evolution
of Hawaii's Mauna Kea volcano, under a grant awarded
by the National Science Foundation.
The $10.3 million, six-year Hawaii Scientific Drilling
Program will be administered by the Hawaii Institute
of Geophysics and Planetology at the University of
Hawaii, in collaboration with the University of California
at Berkeley and the California Institute of Technology.
"Researchers from more than two dozen universities
around the world will be involved in the project,
which will study formation of volcanoes and the mechanisms
that operate within Earth's mantle," says Leonard
Johnson, director of NSF's continental dynamics program,
which funded the grant. "A mantle plume or hot spot
is thought to have produced the string of volcanoes
that make up the Hawaiian Islands chain."
Adds Don DePaolo, a geologist at UC Berkeley, "This
project should give us an unprecedented opportunity
to understand how volcanoes form. We will also retrieve
a detailed record of how the Earth's magnetic field
has changed in the past, and test the extraordinary
but widely held view that Hawaii exists because of
a fountain of hot rock material coming from 3,000
kilometers deep in the Earth."
The project will produce a continuous 14,500-foot
sequence of samples from a bore hole dug into the
inactive volcano Mauna Kea near Hilo on the island
of Hawaii, to better understand a million years of
Mauna Kea volcanism and basic planetary processes.
Researchers will study the samples recovered, as well
as properties of the rocks around the bore hole, to
determine how the volcano was formed, types of volcanic
activity that have occurred, and mantle mechanisms
that produce Hawaii lavas. Other studies will explore
types of volcanic hazards that occur over the life
of a Hawaiian volcano, movement of groundwater deep
within the volcanic complex, and the earthquake cycle
that occurs on the Big Island.
The new project will build on results of the successful
pilot drill hole project completed three years ago
near Hilo. Studies from that work showed that Hawaii's
major volcanoes may be active for periods of almost
a million years, nearly twice as long as previously
thought.
Additional findings of interest are that:
- The frequency of eruptions from Mauna Loa,
a younger volcano arising from the slopes
of Mauna Kea, has slowed from peak activity
500,000 years ago.
- Mauna Kea has subsided (settled) by more than
3,400 feet during the last 400,000 years,
and the surface area of Mauna Loa is shrinking
as the island subsides faster (about 2.5 millimeters
per year) than the volcano builds new flows.
- Fresh groundwater can be channeled to depths
of more than 1,000 feet below sea level by
changes in rock porosity, and cold, deep seawater
can circulate long distances through porous
rocks present at depths of 3,000 feet beneath
the surface of the island.
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