What is the Hawai'i Undersea Geo-Observatory?

The Hawai'i Undersea Geo-Observatory (HUGO) is an automated submarine volcano observatory installed on the summit of the undersea Loihi seamount and connected to the shore via fiber optic cable. Scientists at the University of Hawaii's School of Ocean & Earth Science & Technology (SOEST) will monitor activity on Loihi by collecting data from experiments connected to the HUGO junction box. At its initial deployment in October, 1997, these experiments included a seismometer, a hydrophone and a pressure sensor. Eventually the HUGO project will monitor earthquakes and eruptions, geology, geophysics, biology, hydrothermal venting and other activities on the underwate seamount.

Loihi is located approximately 50 miles due south of Kilauea volcano on the sland of Hawaii. Its summit lies at a depth of about 1000 meters while the deepest part of the seamount reaches a depth of over 5000 m. Loihi is thought to be the youngest expression of the Hawaiian hot spot and may one day become the next island in the Hawaiian chain. The image to the left junction box being loaded onto the R/V Independence for deployment in October, 1997.

The HUGO project is directed by Dr. Fred Dunnebier of SOEST.

HUGO was funded by a generous grant from the National Science Foundation


Location of HUGO on Loihi Seamount

The map to the left shows the summit area and north rift zones of Loihi seamount as viewed from directly above. Visible on the summit are (in red and orange) are three large pit craters, one of which formed during a major seismic event in 1996.

The map to the right shows the location of the HUGO junction box in an enlargement of the boxed area in the righthand figure. The HUGO junction box is located at a depth of 1202 meters in an area known as the "Thousand Fingers Field". The site was so named by Dr. Alex Malahoff for the hundreds of small chimneys in the area formed by hydrothermal activity. When it was first visited, the Thousand Fingers Field was largely exposed rock and hydrothermal deposits. When the HUGO team visited the junction box in January, 1998 the site was found to be covered in an extremely fine, gelatinous mud. The origin of the mud is still under investigation.

Clicking on either image will yield a larger version of that figure.

The HUGO Fiber Optic Cable

The figure to the left shows the route along which the fiber optic cable runs. The 47 km fiber optic cable, as well as ship time to deploy the cable, was donated by AT&T. The far end of the cable is connected to the HUGO junction box. The cable then runs along the Loihi's north rift zone and along relatively flat bathymetric saddle to Honu'apo Bay on the Big Island. There data from the cable are received at the HUGO shore station.

HUGO is controlled via a van on shore at Honuapo, and will soon have 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.

The image to the left shows a portion of the HUGO junction box in its new home on Loihi's summit. A fine mud is visible around the frame. The device with the handle is a tester used on a recent series of dives in the Pisces V submersible. Each of the 10 connectors on the junction box was tested using this device to ensure that data could be transmitted via the optical cable to the shore station. The handle makes it easier for the submersible pilot to manipulate the tester using the Pisces V's mechanical arm.

The HUGO junction box, as well as its instrument packages, are 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.

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This page created and maintained by Jackie Caplan-Auerbach

Last updated Thursday, Feb 19, 1998.