1999 eruption

A small phreatic eruption occurred at Kudriavy volcano on 7 October 1999. It created a new crater 35 m deep and 30–40 m wide and destroyed parts of the summit lava dome. The eruption consisted in several explosions at intervals of 1-2 minutes and produced periodic ash emissions reaching up to ca. 100 m height. Blocks of 20-30 cm diameter were ejected up to 30-40 m. The new crater with vertical walls exposed incandescent hot areas of the interior of the lava dome.
The eruption was preceded by an unusually long dry period during which a large part of the Hot Lake (a rain-water fed lake near the lava dome) had almost dried out. An increase of ground temperature and increased seismic activity caused by changes in the hydrothermal system preceded the eruption and had been monitored since September.
Source: GVP / Smithsonian monthly reports

1992 intense fumarolic activity

Intense fumarolic activity was detected during fieldwork in late 1992. The maximum temperature at fumaroles at the lava dome of Kudriavy volcano was 910°C and rocks at 20-30 cm depth glowed red.

1883 eruption

The last magmatic eruption of Kudriavy volcano was in 1883 and erupted basaltic andesite lava flows in the western crater. Even more than 116 years after the eruption, the temperatures of fumarolic gases exceeded 900 deg C.
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Source:
Korzhinsky et al (2002), "Decade-long study of degassing at Kudriavy volcano, Iturup, Kurile Islands (1990–1999): Gas temperature and composition variations, and occurrence of 1999 phreatic eruption", Earth Planets Space, 54, pp 337–347