Seismic monitoring station installed atop underwater volcano to monitor hazards

Woods Hole Oceanographic Institution (WHOI) researchers have installed a real time seismic monitoring station atop an active underwater volcano in the southeastern Caribbean Sea.

Washington, May 12 : Woods Hole Oceanographic Institution (WHOI) researchers have installed a real time seismic monitoring station atop an active underwater volcano in the southeastern Caribbean Sea.

The new mooring system installed on top of Kick'em Jenny, a volcano just off of the north coast of the island nation of Grenada, promises advance technologies for monitoring geologic hazards in the coastal ocean.

Researchers said it would significantly improve the ability of natural hazard managers to notify and protect the island's residents from volcanic eruptions and tsunamis.

This week, researchers began direct monitoring of the rumblings of the undersea volcano.

Part of a project to develop new technology for earthquake monitoring in coastal areas, the Real Time Offshore Seismic Station (RTOSS) uses an ocean-bottom seismometer (OBS) deployed directly on top of the volcano-250 meters beneath the sea surface-to collect real-time data from Kick'em Jenny.

According to the WHOI researchers, RTOSS employs a special mooring design that allows seismic data to be transmitted by high-frequency radio to a land-based observatory in the village of Sauteurs. It reaches the shore within milliseconds of being collected, which significantly improves the scientists' ability to monitor seismic activity as it happens, a basic requirement for reducing hazards from volcanic gas and rock bursts and from tsunami-generating seafloor avalanches.

A key element of RTOSS, WHOI engineers who designed it, said, is the flexible, stretchy hose that connects the seafloor anchor and instruments to the buoy on the sea surface.

The hose is designed to compensate for the movement of waves, tides, and currents (which are notoriously rough around Kick'em Jenny), and stretches to more than two times its original length without snapping.

Electrical conductors are spiralled through the wall of the hose so that the wires straighten out, rather than break, when the hose stretches.

A surface buoy on the end of the mooring uses solar panels to power the radio transmitters that send the data approximately seven kilometres (four miles) to a shore station near the coast.

"This is the first time that radio telemetry has been used to transmit data from an underwater seismic monitoring station," said Rob Reves-Sohn, an associate scientist in the WHOI Department of Geology and Geophysics and an RTOSS project leader.

According to him, the set up will allow scientists to observe the "inhaling and exhaling" of the volcano as it draws in and expels seawater, magma, and superheated fluids.

"By putting a seismometer right on the volcano, we will significantly improve our ability to detect precursory activity before an eruption takes place," said Reves-Sohn.

ANI