That proved that long periods of time are not essential for fine layers to form.
Radioactive dating of rock that formed since the 1980 eruption gave ‘ages’ of hundreds of thousands, even millions of years, showing that the fundamental assumptions behind radioactive-dating were wrong.
Water often fills the depression to form a lake, as with beautiful Lake Rotorua in New Zealand, created by a volcanic explosion after Noah’s Flood.
During Noah’s Flood some volcanic eruptions covered enormous areas, such as the Columbia River Basalt Group in north-western USA.
After its collapse, more lava is often forced up through cracks around the rim.
Calderas can range in diameter from a few kilometres to more than 50 kilometres.