By INGRID JOHANSON Hawaiian Volcano Observatory
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Although Mauna Loa is Earth’s largest active volcano, it has lived in the shadow of Kilauea since it last erupted in 1984. The geologic record shows that Mauna Loa erupts every seven years on average; however, 37 years have passed since lava flows from the volcano’s Northeast Rift Zone came within 7 km (4 miles) of Hilo.