Jul 9, 2011
About three weeks ago, the Nabro volcano in the East African nation of Eritrea began erupting for the first time in recorded human history. The initial eruption was a violent explosion, pumping vast quanitities of ash and sulfur dioxide into the air above North Africa and the Middle East. Aviation in the region was briefly suspended. Nabro's dark, dense plume of ash and gases shrouded the mountaintop for two weeks, concealing the eruption from view until June 29, when this satellite image was captured.
The image shows that the eruption has transitioned to a quieter, oozing sort of phase. Hot lava glows orange, fading to black as it cools. The lobes at the end of the long lava flow are dark, suggesting that the top of the flow may have crusted over. As the long westward flow cools, hotter, fresher lava appears to be spilling out of the vent toward the south and east.
Nabro is in very arid, dusty country; the green patches in the landscape around the volcano are actually only sparsely vegetated. The image was captured using a combination of infrared and visible light, which misrepresents the degree of vegetation in the landscape.
Although the eruption is a first for the record books, Nabro is in the East African rift valley, where volcanic activity in one form or another is nearly constant. Three tectonic plates are pulling apart from one another in this region, stretching the earth's crust so thin that hot magma from deep below finds numerous weak spots through which to erupt.