![]() atolls or shoals (Midway Atoll is a great example, famous for its role during WWII). Some volcanoes have gone extinct, eroded over time, and now sit barely above sea level, forming low islands, i.e. Landforms borne of active or recently-active volcanoes usually rise well above the water, forming high islands (e.g. If the volcano goes extinct, the corresponding seamount is resigned to a destiny of slow erosion. Eventually, enough material is deposited to for the volcano to rise above water, at which point it is considered a volcanic island. While underwater, oceanic volcanoes form seamounts, but new material is deposited as magma erupts and cools, resulting in growth. Įach oceanic volcano creates some kind of landform, and they are classified based on their height above or below sea level. Note how peak elevation decreases to the left. Elevation of Hawaiian Archipelago above sea level. The islands progressively decrease in elevation to the northwest, until they are near-equal with sea level, and the trend continues underwater as the Emperor seamount chain (Figure 3). Of all the landforms (above & below water) in the Hawaii-Emperor chain, the Big Island is the highest, rising 4481 meters above sea level. In total, the Hawaiian-Emperor chain system stretches over 6,000 km away from the Big Island, with the northernmost seamount Meiji coming within 240 km of mainland Russia. The Emperor seamount chain (named for Japanese emperors) continues as a series of seamounts for another 2,500 km northwest (Figure 2). The Hawaiian archipelago is a group of above-water landforms stretching 3,500 km west from the Big Island-a distance comparable to that between NYC and Salt Lake City. Satellite image of the Pacific Ocean, highlighting some volcanoes of the Hawaii-Emperor Seamount chain. ![]()
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