Fig. 1

Map of the Big Island of Hawaii and the sample location (white star; 19° 30.43′ N, 154° 50.46′ W). Mauna Loa, located on the southern part of the island, is the largest active volcano on Earth (the summit of Mauna Loa is indicated by the lower left red triangle). The highest volcano on the island is Mauna Kea (the summit of Mauna Kea is indicated by the upper red triangle). The lower right red triangle indicates the summit caldera of Kilauea