Scientists use tiltmeters to track long-term changes in the tilting of the ground, helping them identify when the ground is swelling or deflating. The Hawaiian Volcano Observatory has more than 60 GPS stations on Mauna Loa taking measurements to estimate the location and the amount of magma accumulating beneath the surface. Japan’s Mount Fuji is another example of a composite volcano. Their steep, conical slopes are built by the eruption of viscous lava flows and rock, ash and gas. Helens are called composite or stratovolcanoes. Elias National Park has eight shield volcanoes including Mount Wrangell. Shield volcanos are also found in California and Idaho as well as Iceland and the Galapagos Islands. 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. 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. An eruption from the northeast rift zone could send lava toward the county seat of Hilo or other towns in East Hawaii. 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. The west side’s most populous town would be protected from any Mauna Loa eruption by the presence of another active volcano. Lava could reach homes in just hours or days. An eruption from vents on the southwest rift zone could hit residential communities, coffee farms or coastal villages on the west side of the island. That’s where the mountain is splitting apart, the rock is cracked and relatively weak and it’s easier for magma to emerge. Vents generally form along the volcano’s rift zone. Scientists can’t tell far in advance when and where Mauna Loa will open new vents and erupt. The other half of the time it only erupted in the summit caldera. Half the time, the volcano later also began erupting from vents at lower elevations. Each eruption since 1843 started at the summit. Scientists won’t know until the eruption begins. Geological Survey, said data indicates that 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. Frank Trusdell, research geologist at the Hawaiian Volcano Observatory, which is part of the U.S. Its enormous size may allow it to store more magma, leading to larger lava flows when an eruption occurs. Its greater height gives it steeper slopes, which allow lava to rush down its hillsides faster than Kilauea’s. Mauna Loa’s eruptions differ from Kilauea’s in part because it is taller.
0 Comments
Leave a Reply. |
Details
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |