Active seismic is routinely employed by oil and gas exploration firms to gain understanding of subsurface geology. This involves measuring the way in which acoustic waves travel through the Earth’s crust. Much like the way light refracts as it passes through water; acoustic waves alter their speed and direction as they pass through a boundary between different materials. A network of sensors on the surface measure these vibrations and complex software analyses the data to create a map of subsurface geology. This method is ‘active’ because the acoustic waves are produced mechanically either with hydraulic rams on a ‘thumper truck’ to send vibrations through the ground, or for larger areas – dynamite. These vibrations are created on a grid pattern across the area to be surveyed, sometimes as close as 25m apart. This is the reason for the considerable expense associated with active seismic surveying.
ANE intends to use passive seismic tomography to survey the Namibian concession, at a projected cost* of $200 per km² in comparison with $200,000 typical of active seismic. Similarly to active seismic, around 1000 geophones will be installed across the area to monitor vibrations in the earth. However, they will be listening out for naturally occurring vibrations caused by micro-seismic activity, drastically reducing the cost.
The geophone sensing devices will need to connect to the internet and communicate with a central server in order to store the data. However, no communication system currently exists in this remote and sparsely populated region. This has presented an opportunity for ANE to provide a low cost communications network across the region which can be utilized and maintained by local people. This will produce social benefits, as traditional service providers have shunned this area due to the low population and high capital costs involved. Providing internet access to the people living on the concession could facilitate substantial development opportunities.
*Based on: 5000km² surveyed with 1000 x $500 geophones, $100 each to install, $150k for communications system and $250k for analysis of the data