The Dallol Volcano

In Ethiopia, there is an eruption of blue...

Sulfur dust gives the Dallol volcano in Ethiopia's Afar region its stunning blue glow. Earth's lowest land volcano at 157 feet (48 m) below sea level, Dallol is part of the Danakil Depression, where superheated high-pressure gases are released to Earth's surface through vents. When they hit air, the gases ignite the sulfur and fan it into soaring blue flames. If the sulfur reaches its relatively low melting point of 239°F (115°C), it condenses into liquid and flows like electric blue lava.

From National Geographic's "Hidden Earth" which you can purchase here.