Field and Marine Magnetics
Methods and instruments of marine and field magnetics
Team: Thomas Frederichs, Hendrik Müller, Tilo von Dobeneck
Room: University of Bremen, GEO Building, Room 0100
Techniques: Equipped with modern Overhauser magnetometers and gradiometers, we can conduct magnetic surveys at land and in the shallow sea. We also command over professional software for field data processing and interpretation. These systems are extensively used in our field courses and study projects, e.g. for archeological, structural, engineering and marine geology topics.

Magnetic survey training in the Baltic Sea

Portable Overhauser Magnetometer/Gradiometer GEM Systems GSM 19
Team: Hendrik Müller, Thomas Frederichs, Tilo von Dobeneck
Room: University of Bremen, GEO Building, Room 0100
System: We run two GEM GSM-19 (Overhauser) magnetometers for determination of the total intensity of the ambient magnetic field. These devices may be looked upon as a primary standard in mineral exploration and magnetic observatories. The GSM-19 is also used in archaeology, pipeline mapping and other engineering and environmental applications. It is designed to be a mid-range instrument for subsurface exploration.
One of our instruments is equipped with an integrated GPS. Both have an omnidirectional sensor (i.e. no dead zones) and fast sampling rates of up to 5 Hz.

Specifications:
Sensitivity: 0.022 nT @ 1 Hz, (0.015 nT option)
Resolution: 0.01 nT
Absolute Accuracy: +/- 0.1 nT
Dynamic Range: 20,000 to 120,000 nT
Gradient Tolerance: Over 10,000 nT/m
Sampling Intervals: 60+, 5, 3, 2, 1, 0.5, 0.2 sec
Operating Temperature: -55°C to +50°C
GSM 19 Brochure pdf-File (9.05 MB)

Overhauser principle pdf-File (5.17 MB)


Map showing gradiometer data from the ancient Viking settlement Haithabu (Northern Germany). Peak values show probably remains of bed ash from historical forges.

Marine Overhauser Magnetometer GEM Systems and Marine Magnetics Explorer
Team: Thomas Frederichs, Hendrik Müller, Tilo von Dobeneck,
Location: Jacobs Universitity Bremen
System: One of our GSM-19 may be operated in marine mode for which two floating bodies ('fishes') with Overhauser sensors inside instead of the conventional sensors are used. The available cables length of 30 m allows for magnetic surveys on lakes, rivers and inshore areas using small boats.

By courtesy of Jacobs University Bremen we operate a Marine Magnetics Explorer Magnetometer which is designed for a maximum water depth of 300 m. The standard cable length of 50 m limits its use to smaller boats. The Explorer magnetometer may be used for inshore geophysical surveys, archaeology, wreck detection, magnetic mapping of harbours and ferrous target detection in lakes, rivers and estuaries. In order to extent the range of use to larger vessels, a 240 m long cable is available as well.
Marine Magnetics Explorer Magnetometer Website

Marine Magnetics Application Guide pdf-File (450.15 KB)


Marum

Intercoast

Intercoast

Intercoast

IODP

MarTech

AWI

British Antarctic

British Antarctic

British Antarctic

British Antarctic

British Antarctic

British Antarctic

Stud.IP

University of Bremen Research group Marine Geophysics
Faculty of Geosciences | FB5