Raoul Island tsunami detection sensors improved

Published: Wed Oct 4 2017 9:00 AM

With help of the HMNZS Wellington crew and a team of commercial divers, the GeoNet team visiting Raoul Island have had a very successful trip improving the robustness of the tsunami sensors and communications from the island.

The upgrade, repair and hardening of the two tsunami gauge sites was one of the primary tasks for the GeoNet electronics team - they left on 20 September and spent 5 days on Raoul Island, returning to New Zealand on 29 September after a successful trip.

At Fishing Rock, the previous installation included a large “A-frame” structure with a 6-metre-long conduit housing for the old sensors. This needed to be removed and replaced with a less vulnerable installation. The shore platform is very exposed to the environment. The team replaced the GPS timing antenna, cable connections and other sensitive equipment.

Old Fishing Rock Installation

Old Fishing Rock Installation

Protected shore cable at Fishing Rock

Protected shore cable at Fishing Rock

The Boat Cove sensors also had issues, so with the help of our professional dive contractors the team set out to unplug these and install new ones. As the connections of these plugs must remain dry they used an underwater sea-floor “dry-box” to carry out this task. Quite an amazing feat at depth under 2-3 m swells. The team was also undertaking repairs and upgrade work on the seismic station, web camera and the Green Lake volcano monitoring equipment. Green Lake has been the focus of volcanic activity in 2006, 1964, 1870 and 1840.

Geonet Technician  at Moumakai camera

Geonet Technician at Moumakai camera

The electronic team also undertook an upgrade of the data-communications which includes a VSAT data link which is housed by the ‘met station’ building. Our data is transmitted off the island using the VSAT data link. This enables us to get near real-time earthquake, GPS, tsunami and volcano monitoring data from this remote volcanic island. Along with these jobs they also installed a new satellite mount for our main communications dish and inspected all the monitoring and communication sites on the island giving all of them some much needed love.

New antenna installation

New antenna installation

Tsunami gauges are installed around the New Zealand coast and on offshore islands. They transmit the relative sea level data in real time to the GeoNet Data Management Centre and you can view them here. They can provide confirmation that a tsunami has been generated.

The Ministry of Civil Defence and Emergency Management (MCDEM) is responsible for the dissemination of national official tsunami notifications in New Zealand.

We can’t stop tsunamis from happening BUT we can prepare for them. Want to know how? Here are some great places to go to get more information about New Zealand and preparing for tsunamis: