Assertion: volcano | /r/HasProperty | put under observation
Facets:
Source sentences:
text: The earliest reliable written records of historical activity date back to about 1820, and the first well-documented eruption occurred in 1823, when the volcano was first put under observation; although Native Hawaiians are thought to have first settled on the island around 1,500 years ago, oral records predating European arrival on the island are few and difficult to interpret.