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
- 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.