Drilling project to plumb volcanic history

Scientists on the Big Island of Hawaii will drill up to three miles beneath the surface to sample the lava flows that formed 14,000-foot Mauna Kea.

March 19, 1999
Web posted at: 5:10 p.m. EST (2210 GMT)

Scientists in Hilo, Hawaii, this week embarked on a scientific drilling project in an attempt to unearth the history of Hawaii's volcanoes

The Hawaii Scientific Drilling Project -- a cooperative research project involving the University of Hawaii; University of California, Berkeley; the California Institute of Technology and a team of earth science researchers from nearly two dozen universities and research institutes -- will travel a million years into the past by boring thousands of feet down into the volcanic island, according to researchers from the University of Hawaii.

Scientists on the big island of Hawaii will drill up to three miles beneath the surface to sample the lava flows that formed 14,000-foot Mauna Kea. By studying the sequence of lava samples, their chemical compositions, magnetic characteristics and isotopic compositions, researchers hope to uncover the planetary processes that produced the Hawaiian Island chain.

The project is the largest scientific drilling program funded by the National Science Foundation. In addition to revealing new clues about the origin of Hawaiian volcanism, it promises insights into volcanic hazards, the history of Earth's magnetic field and groundwater movement deep within the volcanoes, say University of Hawaii scientists.

The site -- an abandoned quarry located near the Hilo airport -- was selected because it is halfway between the Mauna Kea and Mauna Loa rift zones, reducing the likelihood of encountering intrusive lavas or hydrothermal alteration of the subsurface rocks. Either condition would produce undesirable characteristics in the samples, making the interpretation of their chemical compositions much more difficult.

Scientists will work two six-month drilling intervals using a coring system designed and fabricated especially for the project. The first coring effort is expected to begin in mid-March and site preparation and rig mobilization are under way. Program scientists hope to recover cores to a depth of about 8,000 feet during the initial drilling. The second drilling campaign, to begin in about three years, will push for 15,000 feet.

According to NSF, the primary scientific objective of the project is to learn more about the phenomenon known as mantle plumes, which are jets of very hot, solid rock material that rise through the interior of the Earth from a depth of almost 1,865 miles. Mantle plumes are believed to be responsible for the volcanism in Hawaii, which occurs in the middle of one of the large tectonic plates that constitute Earth's crust.

By studying the lavas of the Mauna Kea volcano, scientists hope to learn more about how mantle plumes originate and how magma makes its way to the surface. Because the lavas to be drilled vary in age from about 1,000 years at the surface to about a million years at 15,000 feet, the core samples will provide a nearly continuous record of the earth's magnetic field over this time interval. Project data will provide the most detailed record ever assembled of how the magnetic field changed over time, say scientists from UH.

For more information, contact Don Thomas, University of Hawaii, (808)974-7398, e-mail: dthomas@hawaii.edu.

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