Because the Carlsberg Ridge is one of the slowest-spreading, and so supposedly less active oceanic ridges, many had thought it unlikely to be the location of a major volcanic eruption.. At ridges such as this, heat is thought to be released more slowly from the underlying magma. However, we may have to rethink that previous assessment. The Carlsberg Ridge region is currently being shaken by a major seismic swarm, which could very well be volcanic in nature. The strongest tremor in the current swarm is a magnitude 5.0. Nature journal said in previous eruption, "A huge plume of hydrothermal chemicals, drifted up to 1.4 kilometers above the vent site and 70 kilometers along the underwater ridge was seen some years ago. It's by far the biggest vent plume ever seen, and confirms that such plumes form following volcanic eruptions at the sea floor, even at slow-spreading oceanic ridges." 1
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The Carlsberg Ridge is the northern section of the Central Indian Ridge, a divergent tectonic plate boundary between the African Plate and the Indo-Australian Plate, traversing the western regions of the Indian Ocean. The ridge of which the Carlsberg Ridge is a part extends northward from a triple point junction near the island of Rodrigues (the Rodrigues Triple Point) to a junction with the Owen Fracture Zone. The ridge started its northwards propagation in the late Maastrichtian and reached the incipient Arabian Sea in the Eocene. Then it continued to accrete basalt but did not propagate for nearly 30 Ma. Then, in the early Miocene it started to propagate westwards towards the Afar hot spot, opening the Gulf of Aden. The Carlsberg Ridge is seismically active, with a major earthquake being recorded by the U.S. Geological Survey at 7.6 on the moment magnitude scale on July 15, 2003. - Wikipedia, The Extinction Protocol