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The ground is shaking and swelling at Mauna Loa volcano, the largest active volcano in the world, indicating that it could erupt.
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Scientists say they don’t expect that to happen right away but officials on the Big Island of Hawaii are telling residents to be prepared in case it does erupt soon. Here are some things to know about the volcano.
Where is Mauna Loa Volcano?
- Mauna Loa is one of five volcanoes that together make up the Big Island of Hawaii, which is the southernmost island in the Hawaiian archipelago.
- It’s not the tallest (that title goes to Mauna Kea) but it’s the largest and makes up about half of the island’s land mass.
- It sits immediately north of Kilauea volcano, which is currently erupting from its summit crater.
- Kilauea is well-known for a 2018 eruption that destroyed 700 homes and sent rivers of lava spreading across farms and into the ocean. Mauna Loa last erupted 38 years ago.
- In written history, dating to 1843, it’s erupted 33 times.
- The Big Island is mostly rural and is home to cattle ranches, coffee farms and beach resorts.
- It’s about 200 miles (320 kilometers) south of Hawaii’s most populous island, Oahu, where the state capital Honolulu and beach resort Waikiki are both located.
Will Mauna Loa erupt like Kilauea?
- Mauna Loa’s eruptions differ from Kilauea’s in part because it is taller.
- Its greater height gives it steeper slopes, which allow lava to rush down its hillsides faster than Kilauea’s.
- Its enormous size may allow it to store more magma, leading to larger lava flows when an eruption occurs.
- Mauna Loa has a much larger magma reservoir than Kilauea, which may allow it to hold more lava and rest longer between eruptions than Kilauea.
- The broad flanks of that volcano, Hualalai, sit between Mauna Loa’s southwest rift zone and Kailua-Kona and would block any lava heading toward the coastal community. An eruption from the northeast rift zone could send lava toward the county seat of Hilo or other towns in East Hawaii.
Will Mauna Loa explode like Mount St. Helens?
- Washington state’s Mount St. Helens erupted in 1980 and blasted more than 1,300 feet (400 meters) off the top of the mountain. Steam, rocks and volcanic gas burst upward and outward.
- Hawaii volcanoes like Mauna Loa tend not to have explosion eruptions like this.
- That’s because their magma is hotter, drier and more fluid, said Hannah Dietterich, a research geophysicist at the U.S. Geological Survey’s Alaska Volcano Observatory.
- The magma in Mount St. Helens tends to be stickier and traps more gas, making it much more likely to explode when it rises.
- The gas in the magma of Hawaii’s volcanoes tends to escape, and so lava flows down the side of their mountains when they erupt.
Shield volcanoes and composite volcano
- Hawaii’s volcanoes are called shield volcanoes because successive lava flows over hundreds of thousands of years build broad mountains that resemble the shape of a warrior’s shield.
- Shield volcanos are also found in California and Idaho as well as Iceland and the Galapagos Islands. Alaska’s Wrangell-St. Elias National Park has eight shield volcanoes including Mount Wrangell.
- Volcanoes like Mount St. Helens are called composite or stratovolcanoes.
- Their steep, conical slopes are built by the eruption of viscous lava flows and rock, ash and gas.
- Japan’s Mount Fuji is another example of a composite volcano.
Reference: IE
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