Scientific drilling in hotspot volcanoes

Article By:

DePaolo, Donald J. Department of Geology and Geophysics, University of California, Berkeley, California.

Stolper, Edward M. Division of Geological and Planetary Science, California Institute of Technology, Pasadena, California.

Thomas, Donald M. Hawaii Institute of Technology, University of Hawaii, Honolulu, Hawaii.

Last reviewed:2007

DOI:https://doi.org/10.1036/1097-8542.YB070430

The term “hotspot” describes a small region of intense volcanism that is located far from a plate boundary. The essential features of a hotspot are embodied in the Hawaiian island chain. The rate of eruption of basalt lava in and near the island of Hawaii is higher than in any other comparable-size area on the Earth, and yet the island is located in the middle of the Pacific plate, thousands of miles from the nearest plate boundary. The standard explanation for the Hawaiian volcanism is that a plume of exceptionally hot solid rock material is rising within the mantle under Hawaii. The plume is envisioned as a roughly cylindrical region, 200–300 km (120–190 mi) wide, extending from about 100 km (60 mi) below the Earth's surface all the way down to the core-mantle boundary 2900 km (1800 mi) below the surface. For Hawaii, the plume has been nearly stationary for the last 60 million years, whereas the Pacific plate has been moving at 8–10 cm/year (3–4 in./year) to the northwest over the plume. This situation has resulted in a chain of volcanoes more than 5000 km (3000 mi) long that extends from the island of Hawaii to the northwestern-most part of the Pacific. Many volcanoes on other planets in the solar system, such as Mars and Venus, are believed to form by processes similar to those that produce hotspot volcanoes on the Earth.

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