Water temperatures where lava enters the sea

In this view of a lava entry point, the concentric color patterns visible on the ocean's surface represents several distinct temperature zones. The yellow-brown zone ranges from as high
as 69 degrees C near the lava contact to about 35 degrees 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.

Inside the horseshore-shaped yellow-brown zone, the surface water temperatures are about
23 - 25 degrees 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. By the time the rising water reaches the surface, its temperature is only 2 - 5 degrees above that of normal seawater. This usual contrasting dark blue color of the ocean is
obscured by the weather clouds in the lower left corner of the photograph.

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

Waves send scalding water onto new land
Several people have received second-degree burns from hot seawater that was swept onto
shore where they were watching lava entering the sea. Because the hottest water is along the shoreline, 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
surfes onto shore.

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