A submarine eruption was reported in 1372 near the Kolbeinsey Ridge NW of Grimsey Island.  Kolbeinsey Island, the only subaerial expression of this portion of the Mid-Atlantic Ridge, is a small, rapidly eroding island that formed during the late-Pleistocene or Holocene.  Dredged glass shards indicate submarine eruptive activity during the late-Pleistocene until at least 11,800 radiocarbon years ago.  The island was 700 m long in 1616 AD, but had shrunk to 42 m long and 5 m high by 1985 and could be eroded below sea level in the early part of the 21st century.  The Kolbeinsey Hydrothermal Field lies south of the island.  Thorarinsson (1965) roughly plotted the location of the 1372 eruption at about 66 degrees 40 minutes North.  Reidel et al. (2003) note that the location is uncertain, but could lie between the Kolbeinsey Ridge and Hóll Seamount.  Other reports of submarine eruptions north of Iceland have an even more uncertain location (1755) or have been discredited (1783 and 1838).