A bog burst (if that's the correct term for what's seen here), occurs when the pressure of water within soil or peat exerts sufficient force to rupture the surface. The resulting release of water tears away vegetation and the material below it creating the damage seen here. The river in the valley below is New Water.
Uploaded to Geograph by Trevor Littlewood on 13 August 2009
Photo © Trevor Littlewood, 13 August 2009. Licensed for reuse under this Creative Commons licence