A deep research drill hole at Kilauea Volcano, Hawaii

A 1262-m-deep bore hole was drilled at the summit of Kilauea Volcano, Hawaii, to test predictions based on surface geophysical surveys and to obtain information on the hydrothermal regime above a postulated magma reservoir. Data from the drilling and geophysical borehole logs tend to confirm earlier predictions that a mound of brackish or saline water is present above the inferred magma body. Temperatures within the hydrothermal system are not sufficiently high to indicate deposits of economic interest, but the gradient toward the bottom of the hole (approximately 160 m below sea level) is high, about 370°C per kilometer. The maximum temperature, 137°C, is at the hole bottom.