SAND Geophysics resurveys the River Thames for unexploded bombs

Port of London

Flowing through central London, the River Thames is a potentially dangerous confluence of human activity and unexploded ordnance (UXO) leftover from WWII.

So when workers found a 50 kilogram German bomb in the riverbed near the Houses of Parliament during civil engineering work earlier this year, bridges were closed, roads cordoned off, and the Royal Navy and police called in to remove and safely detonate the device.

As a further precaution, the site developer hired SAND Geophysics to work alongside the Port of London Authority Hydrographic Service to resurvey the area. SAND, a geophysical consultancy formed in 2014, uses a combination of multibeam and sidescan imagery, magnetic gradiometry and GeoChirp 3D surveys to identify UXO buried below sea and river beds.

A key component of SAND’s approach was the integration of all of its datasets to provide a higher level of confidence in the results, reducing both the number of necessary diver investigations and the safety buffers required around the targets.

Well suited to this task, Geosoft’s Oasis montaj and UXO software proved to be particularly effective in the Thames project, where vessel traffic and ferrous structures create false anomalies and changing tides play havoc with buoyed sensors.

Read the full story, and interview with SAND’s founder Richard Hamilton, on Earth Explorer.  

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