Peter Melichar

ZAMG, Central Institute for Meteorology and Geodynamics,

Vienna, Austria



Observatory is a basic research center; it is located near the summit

of mount Trafelberg, 1,100 meters ASL, in the province of Lower

Austria. The Observatory consists of two units: the SGO (Seismic

Gravimetric Observatory) realizing seismic and gravity measurements

and the GMO (Geomagnetic Observatory) for geomagnetic research and

standard measurements. Ida F. Conrad, widow of Prof. Victor Conrad,

made a generous donation to ZAMG as part of her legacy. This funding

allowed me to start planning a new geophysical observatory in 1975 on

behalf of ZAMG. The ‘Conrad’ endowment to ZAMG was finally the

starting point for creating a new research center partly funded by the

Federal Ministry of Science and Research and partly by the government

of Lower Austria. Its first task was to consider replacing the

geophysical observatory on the Cobenzl Mountain near Vienna. This was

built in 1952 after the Second World War as a more than provisional

solution. Quality of measurements dropped due to ever increasing

disturbances from the city of Vienna. In 1975 I therefore started the

search for a new observatory site in low noise areas for seismic and

magnetic measurements in Lower Austria. I focused on the eastern edge

of the Limestone Alps given the non-magnetic limestone and the

untouched nature. Trafelberg is free from watercourses and sources,

which are natural facts of disturbances. The forests surround the

observatory site as preservation areas. Natural and man-made

disturbing factors are far enough away from our site and yet travel

time to Vienna is just one and a half hours. As part of my

investigations within the framework of the first Austrian aeromagnetic

survey in 1978, I discovered a large undisturbed area around

Trafelberg. In 1979, I carried out the first soil measurements with a

portable VARIAN cesium gradiometer-magnetometer with a resolution of

0.1 Nano Tesla on Trafelberg. I chose an underground construction as

design variant, which makes the observatory - a geophysical laboratory

- independent of the seasonal fluctuations. In the tunnel system, the

temperature of + 7 ° Celsius remains fairly constant. This is a real

gift the mountain offers and it brings ideal conditions for highly

sensitive sensors and electronics – leading to a most significant

low noise reduction. Air conditioning is not required such avoiding

electromagnetic interference and considerable energy costs. In 1998

the so-called ‘New Austrian Tunneling Method’ was used for the

SGO. In 2010 the non-magnetic GMO tunnel system was built by ÖSTU

STETTIN in a special modification of the new Austrian tunnel

construction technique. White cement and lime, fiberglass anchors,

fiberglass grids and mats were the materials used. The entire tunnel

system of the GMO with over one kilometer in length was manufactured

using this special tunnel construction method. The CONRAD Observatory,

with its two separated underground sections SGO and GMO, has a total

tunnel length of 1,166 m with 8 up to 200-meter deep boreholes

accessible from the tunnel floor. I planned the GMO as a standard

Observatory having the ability to accommodate additional scientific

magnetometer systems. My vision for the GMO was a central heart. It is

the 3D gradiometer magnetometer system from GEM Systems. In its

configuration, it is currently the world's most sensitive measurement

system of its kind. It includes two horizontal gradiometers in

north-south and east-west directions as well as a vertical

gradiometer. The maximum extension on the three axes x, y and z is 200

meters each. In addition, a variable gradiometer system was integrated

for smaller distances between 5 and 50 m. Measurements in the Femto

Tesla range are now carried out with these potassium sensors, which

have a resolution 100,000 times higher than those of my cesium sensors

in 1979 when I did my first measurements on Trafelberg. Everyone knows

that Earthquakes can not (yet) reliably predicted ... But it is known

that due to the pressure build-up in the earth's crust just shortly

before an earthquake happens very small electromagnetic signals are

generated in the rock masses. This leads to induction and

piezoelectric effects, which then cause extremely small changes in the

current systems of the ionosphere. Due to the extreme resolution of

the 3D gradiometer on the GMO up to the Femto Tesla range, these

magnetic precursor effects may be recorded and analyzed for the first

time. This, in combination with the seismic measurements at the CONRAD

Observatory, offers a potential opportunity for the development of new

and more reliable earthquake prediction models. Monday, June 16, 2008,

I had the honor to present the GMO at the Geomagnetic Observatory

Workshop IAGA 2008 in Boulder, Colorado.

What started for me, as a challenge at a young age became my vision.

Finally realized after 40 years. Today I am happy to be a part of it.