Figure 4.23 High-resolution black and white Digital Globe™ satellite imagery (WorldView-1) showing the presence of an 8-m high pingo-like mound on 9 June 2013 (left) and the same location on 15 June 2014 revealing the recently discovered Siberian crater (right). The height of the mound prior to crater formation was estimated using shadow length and sun angle at the time the image was acquired. The red line shows the outline of the surrounding ‘parapet’. The yellow line delimits the area where the chunks of soil ejected from the crater were found (Kizyakov et al., 2015).