Arising approximately NUMBER@1 million years ago , the LOCATION@1 , LOCATION@2 's only shield volcano , is also LOCATION@3 's largest basalt formation , consisting of a multitude of layers which , having flowed over each other , fall downward from their peak in ring-shaped terraces to the base .

The LOCATION@1 is about NUMBER@1 million years old and is LOCATION@2 's only shield volcano and the largest basalt formation of LOCATION@3 . It consists of many layers which fall downward from their peak in ring-shaped terraces to the base .
