This week at Mawson: 16 September 2016

Tony is the communication technician at the station and is responsible for making sure our internet, phone system and radios are all working. One of the other jobs that Tony takes on every week are the magnetic obs.

The magnetic absolute building is a little hut that was brought over from Heard Island in 1955. It sits in isolation from the rest of the station, located past the equipment parking area and the emergency food containers, towards the glacier edge. The reason for the isolation is to try and reduce any interference by metal objects on the magnetic field measurements.

Tony uses a declination-inclination magnetometer and a total field intensity magnetometer to measure both the direction and strength of the magnetic field. It takes about an hour to take the measurements, at times using the little window in the door to line up with a stake outside. Other measures use little marks all over the inside of the hut that people have created over the years.

It is an interesting process, actually that’s a little bit of a lie, it is a pretty boring process to watch. What happens to the results is very interesting; Geoscience Australia maintains a national network of geomagnetic observatories which forms part of a global observatory network.

Geoscience Australia uses the data measured in our little hut to show how the earth’s magnetic field changes in the Australian region due to processes taking place beneath the earth’s surface, in the upper atmosphere and in the earth-sun space environment.

This data is then used in mathematical models of the geomagnetic field, to monitor space weather, and for scientific research. The resulting information can be used for compass-based navigation, magnetic direction finding, and to help protect communities by mitigating the potential hazards generated by magnetic storms.

The Australian Radiation Protection and Nuclear Safety Agency, more generally known as ARPANSA, is the national agency that helps to support Australia’s involvement in the comprehensive nuclear test ban treaty.

The comprehensive nuclear test ban treaty was signed on the 24^th September, 1996 and ratified on the 9^th of July, 1998. Another 182 countries are also signatories of the treaty, which involved the creation of a international monitoring system that monitors compliance with the treaty.

At Mawson we have a seismic and radionuclide monitoring system that the station communication technician and station leader monitor on a daily basis.

Seismic monitors detect vibrations in the earth’s crust. The principal use of the seismic data in the verification system is to locate seismic events and to distinguish between an underground nuclear explosion and the numerous earthquakes that occur around the globe.

The radionuclide system can detect radioactive debris from atmospheric explosions or vented by underground or underwater nuclear explosions. The presence of specific radionuclides provides unambiguous evidence of a nuclear explosion. To detect radioactive debris we go through a daily routine in the ARPANSA lab on station.

The first step is to place a piece of special filter paper into a frame and expose it via a high volume air sampler for about 24 hours. The filter paper is then crushed into a small disk and left to ‘decay’ for another 24 hours; the decay process allows naturally occurring radionuclides to be removed. Finally the disk is placed in the gamma detector to be analysed. The data is automatically transmitted to the international data centre in Vienna for collation and review.

It is an interesting process to be a part of and has been a great opportunity to learn more about Australia’s involvement with an international monitoring system.