Short-lived submarine activity was discovered by a fishing vessel on 26 May, about north-east of Heimaey and off the coast of the mainland. The eruption finally came to an end in early July, when flowing lava was no longer visible, although subsurface flows may have continued for a few days longer. Shortly before the end of the eruption, a tiltmeter 1150 metres (3750 ft) from the crater which had been measuring ground deformation throughout the eruption detected subsidence towards the crater, implying that the shallow magma chamber which had fed the eruption was emptying out.