About HUGO

The National Science Foundation (NSF) has just awarded $900,000 for the project to Dr. Fred Dunnebier of SOEST. The undersea observatory's instruments will include seismometers, tilt meters, bottom pressure sensors, cameras, thermal and chemical sensors. It will monitor earthquakes and eruptions, geology, geophysics, biology, hydrothermal venting and other activities on the underwate seamount. The observatory will be placed on or near the summit of Loihi, which is about 3,160 feet below the ocean surface.

The project should "shed new light on the early behavioral statges of hot-spot volcanoes and submarine volcanic activity in general," says Duennebier.

Here is an image of Loihi provided by John R. Smith jr. The contours you see are every 1 km from -5 km to -1 km. Loihi is growing from the hot spot in the Earth's crust that created the rest of the Hawaiian Islands over several millions of years. As the Pacific crustal plate moves, the hot spot stays relatively stationary, giving birth to a series of islands, the Hawaiian island chain. As, earlier, it created seamounts further up along the chain to the northwest that were once islands, but have long ago sunk below the surface of the ocean). Loihi will some day, probably become the next Hawaiian island in the chain, after the Big Island.

The underwater observatory will be connected to the shore of the Big Island (about 21 miles away) via fiber optic cable donated by AT&T, which will donate ship time to lay it on the ocean floor from Honuapo, on the Big Island's east coast, to Loihi.

Here is the planned route for the optic cable. The proposed fiber optic cable route for HUGO runs from Honuapo Bay along the relatively flat bathymetric saddle and up Loihi's North Rift Zone to its summit. Here it will connect to the main splitter from which sub0nets will be strung by the Pisces V submersible.

Scientists have been studying Loihi with submersibles for several years, and have already emplaced an instrument package from Scripps Institute of Oceanography (California) that will be plugged into the new underwater observatory. The new underwater observatory is tentatively named the Hawaii Undersea Geo-Observatory (HUGO). But submersible expeditions are very expensive, and so far haven't been present during an active eruption of Loihi to see what actually goes on there during an eruption, though they have emplaced underwater seismic instruments. Those, and similar instruments on the Big Island have recorded several series of eruptions of Loihi. Submersibles, particularly the Pices V, operated by the Hawaii Undersea Research Laboratory (also part of SOEST) will still be used to emplace and service the instruments.

Key instrument packages will be made of titanium, to minimize corrosion and ensure a life span of at least 10 years, according to Dave Harris, chief engineer of the projects. The tough parts are the electronics, mechanical design, and software, he claims, "Other than that, it's easy."

Power for the instruments will be supplied via the same cable that holds the optic fibers. Average power use will be about 50 watts.

HUGO will be controlled via a van on shore at Honuapo, with a data link to the USGS Hawaiian Volcano Observatory on Kilauea. The Pacific Tsunami Warning Center in Honolulu will receive a direct data feed from the pressure sensors.

Here is a slightly different image of Loihi by J.R. Smith, from the same viewpoint. Like the image above, it is a 3-dimensional shaded relief perspective image of the Loihi submarine volcano 30 km off the southeastern coast of the island of Hawaii. The views are from the southwest at an elevation of 30 degrees with illumination from the northwest. Data used include GS multibeam bathymetry (from NOAA's Coast & Geodetic Survey), NOS nearshore hydrographic soundings, and USGS topography.

Loihi is a geologically active seamount rising from a basal depth of over 5 km to a summit just shallower than 1 km. South and North Rift Zone comprise the backbone of the volcano. Two pit craters and several cones define the summit. Active hydrothermal venting and bacterial mats are located at Pele's Vents, on the southern end of the summit. The coast of Hawaii Island is seen in the background, with Honuapo Bay on the left edge of the image.

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