Stage 1 Stage 1 is sometimes referred to in more detail as the pre-shield alkalic stage. It is unknown whether east Maui or other volcanoes of the chain must go through a pre-shield alkalic stage. The lava of stage 1, if present, was subsequently buried by products of succeeding eruptive stages. Stage 2 Stage 2 is the shield-building stage. Over 95 percent of a Hawaiian volcano's volume is emplaced during shield building, during a period that typically spans about 600,000 years.
Early eruptions are entirely underwater, but the rate of upbuilding exceeds the rate of subsidence.
The volcano grows to reach the ocean surface and becomes an island about midway through its shield-building years, after about 300,000 years. At East Maui volcano we see the final lava flows of the shield-building stage in exposures along the north shore of the island from Honomanu Stream eastward to Nahiku. That's because East Maui's Honomanu shield is obscured by younger rocks. The third volcanic stage is the capping or post-shield alkalic stage. East Maui entered its capping stage about 900,000 years ago.