Geology

Shared Plumbing

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Science  20 Oct 2000:
Vol. 290, Issue 5491, pp. 409
DOI: 10.1126/science.290.5491.409d

Most volcanoes occur either in chains along a volcanic arc or in clusters, and each volcano may have several active vents. A major question in geology is how and whether these vents and volcanic centers are connected at depth. The island of Hawaii, Earth's most active volcanic system, is composed of seven volcanoes and the most recent eruptions of each volcano have slightly different compositions, due to the evolution of each center as it ages.

Kauahikaua et al. performed detailed gravity measurements on Hawaii and offshore to examine how the volcanic systems are connected beneath the surface. Gravity measurements are useful because dense minerals accumulate in the dikes and subsurface intrusions that feed the edifices during eruptions; these perturb the Earth's local gravity field. Fine-scale measurements were used to resolve features at depth and to remove the regional effects of the large mass of volcanic rocks that form Hawaii. The data imply that the plumbing systems of at least some of the volcanoes are connected at depths of 10 to 14 km, perhaps along relic cracks or faults in the Pacific Ocean plate. — BH

Geology28, 883 (2000).

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