Saturday, February 24, 2018

Geomagnetic and Geoelectric Department

Geomagnetic and Geoelectric (Applied Geophysics) Department is considered one of the main and effective geophysical departments at National Research Institute of Astronomy and Geophysics as it has a lot of activities that play a vital role in the scientific society. It also has a wide range of aims that has a strong and direct relation with the requirements of the government and the individuals. The department consists of two laboratories; Geomagnetism laboratory and Geoelectric and Geothermal Laboratory.

Geoelectric and Geothermal Laboratory focuses on many targets like groundwater explorations, Geothermal explorations, mining explorations, Archaeological investigations, detection of Geotechnical and Engineering problems and providing reasonable solutions to many of them. Geoelectric and geothermal lab. has the latest geophysical techniques (Electric and Electromagnetic techniques) that can achieve these targets and give accurate results.

Geomagnetic laboratory focuses on many goals such as studying the geomagnetic activities and space weather studies related to magnetic storms, sub storms and geomagnetic pulsations. The Lab operates two geomagnetic observatories record the magnetic field during the 2 hours and responsible for detection of the magnetic storms. In addition to assessment of the subsurface structures and their depths. Also, the paleomagnetism represents one of the main trends in the geomagnetic lab.

Devices of the Department

SIR4000 control unit (GSSI)

Applications:

Ground Penetrating Radar is an electromagnetic technique used for high-resolution detection, mapping and imaging of the subsurface soils and rock conditions. It investigates the subsurface conditions by transmitting radio waves into the ground and recording the response at the ground surface. This system has a capability to investigate the subsurface medium at different depth levels according the used antenna. Each antenna is designed to operate over a range of frequencies. The high frequency is related to shallow investigations and the low frequency is corresponding to deeper investigations. It is strongly used for Archaeological Investigations.

Syscal R2 used for Vertical Electrical Sounding (VES)

Applications:

This instrument is used for measuring the electrical resistivity Distribution in the subsurface medium. This is carried out by injecting an electric current through a pair of electrodes into the ground and measuring the potential difference through another pair of electrodes to detect the subsurface geological layers and groundwater aquifers.

Syscal R2 with Multi Electrode System that used for constructing Electrical Resistivity Tomography Profiles.

Applications:

This instrument is used for measuring the electrical resistivity Distribution in the subsurface medium. It can be used for detecting underground fractures, cavitied, shafts. it is also used in Archaeological Investigations.

RM15 Resistance meter

Applications:

RM15 Resistance meter is measured the changes in the electrical resistivity which near to the surface only for 5 meter. The ideal uses of this instrument for the archeological prospecting.

Sirotem

Applications:

This instrument detects underground conducting materials by transmitting electrical pulses along loops of cables laid out on the ground surface. It is unique in having the transmitter and receiver in a single unit. It is used for ground water explorations.

T-VLF

Very Low Frequency Instrument(T-VLF), IRIS company

Applications:

VLF method utilizes Very Low Frequency radio communication signals in the range of 15-30 KHz, to determine electrical properties of near surface soils and shallow bedrock. The technique is valuable especially for mapping steeply dipping structures such as faults, fracture zones and areas of mineralization.

Multiple Frequencies Electromagnetic Profiler

Applications:

This instrument has transmitting and receiving coils in the same unit. The instrument is designed to simultaneously measure the electrical conductivity at six frequency values ranging from 330 Hz to 20 KHz with fixed inter-coil separation.

Geothermal activity meter

Applications:        

It’s used for measuring the geothermal gradient through pore whole and thermal conductivity of rocks to calculating the heat flow values to elucidate the geothermal areas. It’s useful in many economical purposes (renewable energy).

STRATAGEM

Applications:

The Stratagem is a unique Magnetotelluric (MT) system used for measuring the electrical resistivity of the earth over depth ranges of a few meters to greater than one kilometer. This system uses both natural and man-made electromagnetic signals to obtain a continuous electrical sounding of the earth beneath the measurement site. It is used for ground water investigations.