New research suggests that some of the largest volcanoes on our planet form significantly faster than previously thought. Researchers from the United States, have been investigating the crystallisation of quartz in the magma body that caused that massive Bishop eruption ~760,00 years ago at Long Valley, California. Previous research had focussed on the radiometric dating of whole rock, glass, zircon and feldspar, which suggested that the magma body evolved slowly over as long as 100,000 years.
This new research has examined the processes which impacted upon quartz crystallisation, which begins when a body of magma forms and stops when it erupts. These techniques, including the examination of growth rates and fluid inclusions, led the team to conclude that most of the magma bodies form over a period of between 500 and 3000 years, followed by the eruption of the caldera. Calderas are the most explosive of all volcanic eruptions and are responsible for historical eruptions such as Tambora (1815) and Krakatoa (1883).
Another interesting (and important) factor about this research is that it was published in PLoS ONE, which an open access journal, meaning that anyone who wants to can access it. The BBC also has a good article about the research.