Kawah Ijen, Indonesia

  It's not actually blue lava it's sulfuric gas igniting at 600°C as it hits oxygen. 

  And certainly if you look at its videos , there is lava too mostly  "underground" and Just not much flowing outwards and the flowing things  are usually liquid sulphur . At 115ºC 

용암이 아니라 sulfuric gas 랍니다.