Page 2 HA09
IMS Station Location and Profile
Tristan da Cunha hosts one of the IMS's 11 hydroacoustic stations used to detect natural and man-made phenomena in the oceans, including underwater nuclear detonations. This so-called T-Phase station is one of five of this type located on oceanic islands and utilizing seismometers to detect acoustic waves that are converted to seismic waves once they hit land.
The Hydroacoustic T-phase station HA09 consists of two three-component seismometers. The northern one is located near the settlement Edinburgh-of-the-Seven-Seas about 500 m from the coast while the western one is located on a flat area called Potato Patches about one kilometre from the sea.
In each element site, three principal sub-structures can be found: a data acquisition system, power supply system and satellite communications system. At the northern element site near the village, cultural noise includes people, vehicles, etc. Although livestock are virtually the only source of human-related noise in the vicinity of the western element site, this area is subject to extreme sporadic winds.
This exposure to winds that can transport both infrasound sound waves and airborne radionuclide particles from afar makes the island of Tristan da Cunha ideal for infrasound and radionuclide measurements. The absence of larger human settlements and traffic allow for high-precision seismic and infrasound measurements. The island was therefore also selected to host infrasound station IS49 and radionuclide station RN68. This particular trilogy of IMS stations is also found on another remote British overseas territory, the British Indian Ocean Territory (BIOT).
Contributing to the Develpment of the Island
With the establishment of the three IMS stations, a continuous power source was installed at Tristan da Cunha. This power source also provides electricity free of charge to the few homes on the island for eight hours at nighttime, who now enjoy, an uninterrupted power supply for the first time. The IMS stations have thereby contributed to the life and economy of the island. The Tristan da Cunha Government has devoted a part of its website to the IMS stations on the island.