In cooperation with a partner company, our office can provide the geophysical instruments, the auxiliary equipment and the corresponding software for processing and interpreting geophysical measurements, so that it can apply (depending on the objective, the desired investigation depth, and the natural and technical particularities of the survey area) any combination from a series of geophysical methods.
The geophysical methods that the office is able to perform in combination cover a very wide range of applications in geological research, environmental investigation and geotechnical engineering, the main ones of which are:
- Research and location of underground aquifers. Management of water potential (mapping of subsurface flows and spring recharge zones). Studies of groundwater aquifer recharge.
- Research and prospecting for deposits.
- Location and spatial assessment of ore-bearing zones.
- Research of geothermal fields.
- Design of drilling research programmes.
- Geological – tectonic – seismotectonic mapping.
- Mapping and determination of stratigraphy, rock quality, hydrogeological conditions and subsurface morphology.
- Study of ground instabilities, subsidence, landslides and soil creep.
- Location, mapping and study of the geometric characteristics of geological faults.
- Research and location of caves, galleries, cavities, conduits, underground tanks and karstic structures in general.
- Research and determination of leaks in dams, reservoirs, sewers and underground conduits and tanks of any kind.
- Assessment of the suitability of waste disposal sites, sanitary landfills (ΧΥΤΥ and ΧΥΤΑ)
Geophysical methods
Electromagnetic sounding methods: transient-field TEM and NANOTEM
The office has the following geophysical instruments: GDP-32 receiver (6 channels), ZT 30 Transmitter (max output current 30A), NT 20 Transmitter (max output current 20A), NANOTEM receiver, XMT-32 Controller and TEM-3 Magnetic sensors, by the American company ZONGE ENGINEERING.
For the processing and interpretation of the measurements we use the DATPRO and STEMINV software.
For taking the measurements, the following TEM configurations are applied: In Loop, Moving Loop and Fix Loop.
The depth of the geophysical investigation, depending on the conductivity of the subsurface, the configuration and the dimensions of the loops, can exceed 1200m.
Electromagnetic sounding methods: CSAMT, MT and AMT
Controlled Source Audio-frequency Magneto Tellurics (CSAMT)
Natural source magnetotellurics (MT) and audio-frequency magnetotellurics (AMT)
The office has the following geophysical instruments: GDP-32 receiver (6 channels), ZT 30 Transmitter (max output current 30A), XMT-32 Controller and ANT-3 and ANT-4 Magnetic sensors, by the American company ZONGE ENGINEERING.
For the processing and interpretation of the measurements, the DATPRO, CSAMT, EM2D and SCS2D software is used.
The depth of the geophysical investigation, depending on the frequency used to take the measurements (0.125 to 8,000 Hz), the dimensions of the dipole (transmitter - receiver) and the conductivity of the subsurface, can exceed 1500m.
Electromagnetic method of Ground Penetrating Radar (GPR)
We have four Ground Penetrating Radar systems, three by the Swedish company MALA and one by the Norwegian company 3d-Radar. All are capable of producing two-dimensional and three-dimensional imaging of the targets under geophysical investigation. The systems are:
- The 3D-Radar GPR system. It is a pioneering new-generation construction of three-dimensional ground penetrating radar (3D GPR) using step-frequency radar technology and an innovative multi-channel antenna design. The following antennas are used: Model B1847, with continuous frequency coverage from 200MHz to 2.0GHz, 1.8 meter array length and 47 antennas elements; Model B1823, with continuous frequency coverage from 100MHz to 2.0GHz, 1.8 meter array length and 23 antennas elements. For the processing and interpretation of the GPR measurements, the following software programs are used: Slice v.7, Examiner, Reflex and Reflex3D.
- The Mala ProEx (Professional Explorer) system with shielded antennas of: 250MHz, 500MHz, 1000MHz, 1600MHz, 2300MHz and the unshielded RTA antennas of 25-30MHz, 50MHz and 100MHz.
- The GX HDR (Ground Explorer High Dynamic Range) system with shielded antennas of: 80MHz, 160MHz, 450MHz and 750MHz. For the processing and interpretation of the GPR measurements, the following software programs are used: Slice v.7, Objectmapper, Geovision and RADExplorer
- The Mala GPR (Professional Explorer borehole logging system), with two pairs of optical (four-strand) cables 800m long each and the unshielded borehole antennas: 100MHz and 250MHz. Measurement configurations: Downhole and Crosshole. For the processing and interpretation of the GPR measurements, the following software programs are used: Radinter and Wintomo.
The depth of the geophysical investigation, depending on the antenna used and the conductivity of the subsurface, ranges from 0.30cm to 50m.
EMI electromagnetic method (Time Domain)
The office has two survey systems by the Canadian company GEONICS, capable of producing two-dimensional and three-dimensional imaging of the targets under geophysical investigation. The first system is the Geonics EM61 MK2 High Power detector, which is the most widely used for UXO surveys and archaeometric research. Its position is determined using the RTK GPS global positioning system.
The system can detect metallic or non-metallic targets at a depth of up to 8m, depending on their size.
The second system is the Geonics EM63 detector, which is used mainly for the classification and orientation of UXOs (unexploded ordnance) or, more generally, buried metallic objects.
SLINGRAM electromagnetic method
The office has two geophysical systems (EMAC 36 and HF EMAC 180) and the Slingram measurement interpretation software by the Swedish company MALA.
The transmission frequencies of the two systems are 3.6 and 18.1 kHz respectively.
VLF electromagnetic method
The office has the WADI geophysical instrument and the SECTOR and RAMAC measurement interpretation software by the Swedish company ABEM.
Magnetic method
The office has the base station, the Magnetometer – Gradiometer G856 and the MAGMAP and MAGPLOT measurement interpretation software by the American company GEOMETRICS.
Seismic methods: reflection, refraction, Crosshole and Downhole
The office has the BISON 9048 - 48 channel seismograph and TERRALOC MARK 6 - 24 channel seismograph seismic recording machines by the Swedish company ABEM. The auxiliary equipment includes the necessary cables, seismic sources and 150 horizontal/vertical geophones of various frequencies (6Hz to 14 Hz). The interpretation of the measurements is carried out with the help of specialised software (WINSISM, SEISIMAGER, etc.)
The seismic profiles can be developed to a length of up to 480 metres.
Electrical methods: electrical resistivity tomography, Complex resistivity and geoelectrical soundings (RES, SP, IP)
Our office has the following four electrical tomography systems, capable of producing two-dimensional and three-dimensional imaging of the subsurface:
- LUND Imaging system (TERRAMETER SAS 1000 (1 channel, max output current 1A & max output power 100W) plus electrode selector ES464 (4 channel & 64 electrodes)) by the Swedish company ABEM.
- LUND Imaging system (TERRAMETER SAS 4000 (4 channel, max output current 1A & max output power 100W) plus electrode selector ES464 (4 channel & 64 electrodes)) by the Swedish company ABEM.
- TERRAMETER LS (4 channel, 64 electrodes max output current 2.5A & max output power 250W) by the Swedish company ABEM.
- MX-30 Multiplex Switch (30 channels, 30 electrodes max output current 5A & max output power 2500W), GDP-32 receiver (6 channels) and ZT 30 Transmitter (max output current 30A), by the American company ZONGE ENGINEERING.
The auxiliary equipment includes electrodes (takeout and non-takeout) and cables for the electrical tomography of 81 electrodes, at spacings of 2m, 5m, 10m, 25m and 50m, providing the possibility for the length of the tomography to be configured from the outset from 160m to 4000m. At the same time, these cables give us the possibility of applying the Roll along procedure, on the basis of which a much larger number of electrodes can be used and at the same time the profiles of the electrical tomography can be developed to whatever length is required to achieve the objectives of the geophysical survey. For the interpretation and presentation of the results, the RES2DINV and RES3DINV software programs by the company GEOTOMO are used.
For carrying out the geoelectrical soundings of electrical resistivity (RES), self potential (SP), induced polarisation (IP) and electrical conductivity, and depending on the desired depth of the geophysical investigation, the following machines are used: Terrameter Sas 1000, Terrameter Sas 4000, Terrameter LS and the MX-30 Multiplex Switch-GDP-32 receiver-ZT 30 Transmitter system. We have electrodes (takeout and non-takeout) and cables up to 5km long for the Wenner and Schlumberger arrays. For the interpretation of the results, the IPI2WIN and RESIX PLUS software programs are used.
The depth of the geophysical survey using electrical tomography can be extended up to 700 metres.
