Near-source erosion or rockfall during a climactic caldera-forming phase of the eruption caused large influxes of lithic blocks into the pyroclastic density cur rents, recorded as widespread lithic breccias.
Conditions were appalling: thick dust, dirt, noise, heat, gas and roof rockfalls with sweating, half-naked bodies covered in coal dust.
Much of the destruction was caused by the numerous landslides and rockfalls which came tumbling down from high above.
The canyon itself still shows activity in the form of rockfalls and landslides.
Engel notes that the party were all nearly obliterated by rockfall while they were crossing the bergschrund.
Power for the colony is supplied by hydroelectric generators, but when a rockfall blocks the underground river, all power is lost.
Landslips and rockfalls are a continuing feature of the evolution of this coast.
However, the route up to the pass had become narrowed and dangerous due to rockfall.
