Pit - John Seach
Summit pit craters
are found in many types of volcanoes and are generally thought to be the
collapse into an underpressured reservoir caused by magma withdrawal.
collapse mechanisms are dependant on the roof aspect ratio (roof thickness/roof
at low aspect ratios (<1)
mechanism occurs at aspect ratios of 1.1-1.2.
A third mechanism
occurs at ratios >1.2
of Pit Craters
(Tanzania), San Cristobal, Telica and Masaya (Nicaragua), and Ubinas (Peru).
Copyright John Seach