© US Geological SurveyThe lava lake in Kilauea’s summit crater (Halemaumau) as it appeared on March 19 2018.
Kilauea, the most active volcano on Hawaii, has been in continual eruption since 1983. It entered a new phase in early May when fractures along a rift on the eastern side of the volcano opened during a series of earthquakes - some of which became volcanic fissures from which lava was erupted.
These fissures allowed magma that had been ponded in a lava summit lake to drain onto the ground surface as lava flows lower down the mountain. This was close to a residential subdivision known as Leilani Estates, where a new volcanic cone has since developed.
Kilauea is buttressed on its north-west side by the enormous mass of Mauna Loa volcano, but its south-east slopes face the ocean and are unsupported. The magma from beneath the volcano usually erupts from the summit of the volcano, and there was a spectacular lava lake there in March. However two rift zones (areas where the volcano is splitting apart), extending east and south-west from the summit, can make it possible for lava to erupt from Kilauea's flanks too.
Comment: More on this spectacular and destructive phenomenon: