Witnessing the birth of volcanic islands is incredibly rare. Locations are often remote, and watery surroundings can snuff out an eruption before magma builds up to the surface. But in 2011, researchers got a bird's eye view of such an event when an underwater volcano began erupting in the Red Sea.
After less than a month, the hot magma had created a new island in the Zubair archipelago near Yemen. A similar eruption gave rise to another island in the same area in 2013. The video above and satellite imagery of the two islands forming were published yesterday in Nature Communications.
Using satellite and video data, researchers at King Abdullah University of Science and Technology in Saudi Arabia were able to map and track the eruptions that created these new islands in the Red Sea. Two cracks in the Earth's crust (called dykes) filled with magma and fueled these eruptions that quickly formed the islands. These troughs are each about six miles long and a little over half a mile wide. After explosive beginnings that produced a lot of land mass, steady magma flow fed the islands' growth.
The newly named Sholan Island and Jadid Island formed on a divergent plate boundary where two tectonic plates are moving away from each other, growing new ocean floor and building a small underwater mountain range. That ocean floor is growing at a quarter of an inch per year, reports Dave McGarvie for The Conversation. "The birth of a volcanic island is a potent and beautiful reminder of our dynamic planet’s ability to make new land," writes McGarvie.
Not only are such eruptions rarely caught on tape, they're also rarely seen in a location like this one. The Red Sea isn't exactly known for its seismic activity. However, around the same time that magma vents in these dykes began erupting, the area experienced a swarm of small Earthquakes. Similar swarms have popped up over the years, and the researchers think the area could be more volcanically active than its reputation suggests.
The islands' lifespan may be fleeting by geologic time standards. Erosion by the Red Sea's waves may be slowly driving them back to the depths. Sholan Island lost 30 percent of its land mass soon after its formation, but erosion rates have dropped. According to Hannah Osborne of IBTimes, the researchers project that the islands will be around for at least a few centuries.
In the 1960s, an underwater volcano produced Surtsey Island off the coast of Iceland, and more recently Japan's Nishinoshima Island experienced a huge growth spurt from volcanic activity in 2013. With little opportunity to observe eruptions, scientists don't actually know that much about the intricacies of how volcanic islands form — let alone how life colonizes such extreme environments.