Hawaiian Volcano Observatory

Water Temperatures Where Lava Enters the Sea

Aerial view of plume rising from lava entry point
Photograph by J. Kauahikaua on May 7, 1998.

In this view of a lava entry point, the concentric color pattern visible on the ocean's surface represents several distinct temperature zones. The yellow-brown zone ranges from as high as 69°C near the lava contact to about 35°C as far as 70 to 100 m offshore. Water is heated at the lava-entry point and moves outward until the long-shore current carries it south along the coast of Kilauea (away from camera). The brown color results from high concentrations of suspended glass fragments broken from cooling lava and from occasional gelatinous zooplankton.

Sea surface temperatures indicated on aerial view of plume rising from lava entry point
Ocean surface temperatures (°C) measured
with a hand-held infrared radiometer.

Inside the horseshoe-shaped yellow-brown zone, the surface water temperatures are about 23-25°C. This is the coolest water near the lava-entry point. At the center of this zone water heated by submarine lava flows mixes with cool water then rises buoyantly to the surface (see sketches below). By the time the rising water reaches the surface, it's temperature is only 2-5° above that of normal seawater. The usual contrasting dark blue color of the ocean is obscured by weather clouds in the lower left corner of the photograph (above).

Sketch by J. Johnson, 1998.

Simplified oblique (left) and cross-section (right) sketches showing surface water isotherms near lava entry point on May 7, 1998.


Infrared Image Reveals Cyclic Pattern

This infrared video frame emphasizes the temperature contrasts of the ocean's surface. White areas represent temperatures above 150° C, which include the steam plume (upper right), the active lava bench, and hot rocks floating on the ocean surface near the entry point. Light gray areas (brown water in color photograph above) surround the dark area of cooler upwelling. Within this dark area are three faint subcircular rings of warmer water that enclose a brighter distinct spot (click image to see these rings more clearly). Infrared video of this area on May 7 revealed a cyclic pulse of upwelling and expansion; a new pulse of slightly warmer water appeared at the surface every 4-8 seconds.


Waves send scalding water onto new land

Steam plume and lava entering ocean

Unexpected large waves caused by normal ocean swells and sudden collapses of an active lava delta often send scalding hot water crashing onto shore.

Several people have received second-degree burns from hot water that was swept onto shore where they were watching lava enter the sea. Because the hottest water is along the shoreline (see sketch above), visitors to the Hawai`i Volcanoes National Park are advised by park rangers to stay at least 400 m inland from an active entry point in case a sudden wave surges onto shore.


Sources of additional information

Tribble, G.W., 1991, Underwater observations of active lava flows from Kilauea volcano, Hawaii: Geology, v. 19, p. 633-636.

Sansone, F.J., and Resing, J.A., 1995, Hydrography and geochemistry of sea surface hydrothermal plumes resulting from Hawaiian coastal volcanism: Journal of Geophysical Research, v. 100, p. 13,555-13,569.

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Updated: 8 June 2000 (SRB)