Over the past 1,100 years, Eyjafjallajökull has erupted four times: in 920, 1612, between 1821–1823, and in 2010. Each of the first three of these incidents directly preceded a major eruption in the nearby subglacial volcano, Katla.[7] There is so far no evidence that Katla will erupt because of its vicinity to the current eruption in Eyjafjallajökull. Katla, which is a much more active volcano, known for its powerful subglacial eruptions and its large magma chamber, much larger than that of the Eyjafjallajökull volcano system, has still not shown any unusual activity, like expansion of the crust or seismic activity. However, one cannot rule out that possibility, since history has shown that Eyjafjallajökull can be a precursor to additional Katla activity.[8] Some geophysicists in Iceland support the notion that the recent volcanic eruption at Eyjafjallajökull may trigger a second eruption at Katla, which would cause a major flooding event due to melting of glacial ice.