Unusual lava type in Hawaii

Latest Eruption had Unusual Features

This Article tells of the detailed work done on the lava flows which destroyed much property in the South East corner of the Big Island of Hawaii.

This involved retrieving lava samples from "live" flows. In Hawaii one expects that the lava will be basalt. Mostly it was, but some of the early lava was richer in silica - it was andesite. This would indicate that the original basalt had evolved (something had happened to it) before it reached the surface.

In this 2015 photo, a scientist from the Hawaiian Volcano Observatory collects a molten lava sample from Kīlauea using a rock hammer. Volcanologists in Hawaii and elsewhere often brave blistering heat and other hazards to gather fresh lava samples for research and to monitor lava properties that can foretell how hot and fluid subsequent flows may be. This monitoring helps authorities plan emergency responses. Credit: U.S. Geological Survey

Is there some unknown magma chamber between the magma source at Kilauea and where it reached the surface?

The article is well worth reading.