the caldera of mendeleyeva stratovolcano kunashir island, russia

activity additional along andesitic autumn avalanche breached caldera calderas central coast considered dacitic dake debris diameter dome domes dominantly eruption fields flank flanks formed geothermal goriachy grew high historical hydrogen inside island japan kunashir kuril lava lie mendeleyeva northern older only outside part phreatic point rausu represent russia scarp smaller solfatara sulfate sulfide unambiguous volcano younger