Historical eruptions have occurred at Sinarka during 1825–1750, 1846, 1855, and the last and largest from 1872 to 1878.

Recent activity is hydrothermal, from a solfatara field with more than 100 fumaroles and several hot, geyser-like springs which erupt water up to 1.5 m (5 ft) high.

A major eruption would not affect large populations; only three people are located within 10 km (6 mi).

The larger sub-peak could be considered its own peak, due to its 540 feet (160 m) of prominence.

This Sakhalin Oblast location article is a stub.