Mauna Kea
Mauna Kea ( or , ) is a dormant volcano on the island of Hawaii. Its peak is above sea level, making it the highest point in the state of Hawaii. Most of the mountain is under water, and when measured from its oceanic base, Mauna Kea is the tallest mountain in the world measuring over . Mauna Kea is about a million years old, and has thus passed the most active shield stage of life hundreds of thousands of years ago. In its current post-shield state, its lava is more viscous, resulting in a steeper profile. Late volcanism has also given it a much rougher appearance than its neighboring volcanoes due to construction of cinder cones, decentralization of its rift zones, glaciation on its peak, and weathering by the prevailing trade winds. Mauna Kea last erupted 6,000 to 4,000 years ago and is now considered dormant. The peak is only about higher than its more massive neighbor, Mauna Loa.
Kīlauea
Together with the outbreak of lava in lower Puna, a lava lake at Halemaumau Crater at Kilauea's summit began to drop on May 2, 2018. The Hawaiian Volcano Observatory warned that the lowering of the lava lake increased the potential for phreatic (steam) explosions at the summit caused by interaction of magma with the underground water table, similar to the explosions that occurred at Halemaumau in 1924. These concerns prompted the closure of Hawaii Volcanoes National Park. On May 17, at approximately 4:15 a.m., an explosive eruption occurred at Halemaumau, creating a plume of ash 30,000 feet into the air. This marked the beginning of a series of vigorous explosions that have produced significant ash plumes from Halemaumau. These explosions, accompanied by large earthquakes and inward slumping and collapse within and around Halemaumau Crater, continued until early August.