this subaerial stage, the flanks of the growing volcanoes are unstable and as a result, large landslides may occur. At least 17 major landslides have occurred around the major Hawaiian islands. This stage is arguably the most well-studied, as all eruptions that occurred in the 20th century on the island of Hawaii were produced by volcanoes in this phase. Mauna Loa and Kīlauea volcanoes are in this phase of activity. Postshield stage As the volcano reaches the end of the shield stage, the volcano goes through another series of changes as it enters the postshield stage. The type of lava erupted changes from tholeiitic basalt back to alkalic basalt and eruptions become slightly more explosive. Eruptions in the postshield stage cap the volcano with a carapace of lava, containing low silica and high alkali contents, the reverse of the stage before it. Some Hawaiian volcanoes diverge from this, however. Lava is erupted as stocky, pasty aā flows along with a lot of cinder. Caldera development stops, and the rift zones become less active. The new lava flows increase the slope grade, as the aā never reaches the base of the volcano. These lavas commonly fill and overflow the caldera. Eruption rate gradually decreases over a period of about 250,000 years, eventually stopping altogether as the volcano becomes dormant. Mauna Kea, Hualālai, and Haleakalā volcanoes are in this stage of activity. Erosional stage After the volcano becomes dormant, the forces of erosion gain control of the mountain. The volcano subsides into the oceanic crust due to its immense weight and loses elevation. Meanwhile, rain also erodes the volcano, creating deeply incised valleys. Coral reefs grow along the shoreline. The volcano becomes a skeleton of its former self. Kohala, Māhukona, Lānaʻi, and Waiʻanae volcanoes are examples of volcanoes in this stage of development. Rejuvenated stage After a long period of dormancy and erosion of the surface, the volcano may become active again, entering a final stage of activity called the rejuvenated stage. During this stage, the volcano erupts small volumes of lava very infrequently. These eruptions are often spread out over several millions of years. The composition of the lavas erupted in this stage is usually alkalic. The stage commonly occurs between 0.6 and 2 million years after it has entered the weathering cycle. Koʻolau Range, West Maui, and Kahoʻolawe volcanoes are examples of volcanoes in this stage of development. Note, however,