https://phys.org/news/2018-06-volcano-hawaii.html

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 erupts from Kilauea's flanks too.

The current activity is based along the east rift zone. According to the US Geological Survey, 23 separate new fractures there became volcanic fissures from which lava was erupted. By the end of May, "fissure 8" (the eighth new fissure to have announced itself) had become dominant – with activity at the others ceasing or subsiding. This was the source of the lava that by June 4 was flowing into the sea several miles away near the Vacationland resort, where it completely filled what had previously been Kapoho Bay.