Occurrence of Attributes in Original Text

The text related to the cultural heritage 'Ngorongoro Conservation Area' has mentioned 'Volcano' in the following places:
Occurrence Sentence Text Source
Ngorongoro Volcano (2.5xe2x80x931.9 Ma) is primarily basaltic trachyandesite.
[18] The crater, which formed when a large volcano exploded and collapsed on itself two to three million years ago, is 610 metres (2,000 feet) deep and its floor covers 260 square kilometres (100 square miles).
[11][19] Estimates of the height of the original volcano range from 4,500 to 5,800 metres (14,800 to 19,000 feet) high.
[21] The Ngorongoro volcano was active from about 2.45 to 2 million years ago.