In 1965 the activity on the main island diminished, but at the end of May that year an eruption began at a vent 0.6 km (0.37 mi) off the northern shore. By 28 May an island had appeared, and was named Syrtlingur (Little Surtsey).The new island was washed away during early June, but reappeared on 14 June.ffusive eruptions continued until 1965, by which time the island had a surface area of 2.5 km 2 (0.97 sq mi). On 28 December 1963 submarine activity 2.5 km (1.5 mi) to the north-east of Surtsey caused the formation of a ridge 100 m (328 ft) high on the sea floor.