Lvinaya Past (Russian: Львиная Пасть, literally "Lion's Maw", after a rock that emerges from the sea and resembles a sleeping lion), also known as Moekeshiwan (Japanese: 萌消湾), is a volcano in the southern part of Iturup in the Kuril Islands, administered by Russia and claimed by Japan.

Iturup island contains about nine stratovolcanoes, some pyroclastic cones, one somma volcano and several geothermal fields.

[8]: 64 Ice cores taken in the Siberian Altai Mountains demonstrate increased sulfate concentrations at the time, possibly stemming from large sulfate release by the eruptions of Lvinaya Past and contemporaneous large scale activity at Caldera Fisher in Alaska and Pinatubo in the Philippines[5]: 419  and may relate to the Younger Dryas event.

[11]: 148  The development of alder-containing birch forests in the region may have been favoured by the ash fall from the eruption, which would have killed more susceptible conifers.

[8]: 73 Other volcanoes on Iturup include Astonupuri, Baransky, Berutarube, Bogatyr Ridge, Chirip, Demon, Golets-Tornyi, Grozny Group, Medvezhy and Past.