© Hollyn Johnson/Tribune-HeraldMauna Loa is seen Saturday morning from West Hawaii. -
As Kilauea continues to threaten lower Puna, geologists are also keeping their eyes on the volcano's much larger cousin - Mauna Loa. According to the U.S. Geological Survey Hawaiian Volcano Observatory, Mauna Loa, the largest active volcano on the planet, has been rumbling and showing signs of awakening for more than a year.
An eruption isn't imminent, and no warnings are being issued, but the towering 13,678-foot mountain is going through the same motions that it did before its 1984 and 1975 eruptions, said Wes Thelen, HVO seismologist. The activity includes faint, shallow earthquakes to the west of the summit and "deep long period" temblors 28 to 31 miles below the surface, both of which point to the intrusion of magma.
"All the signs are there that tells us that magma is moving into the shallow system," Thelen said. He said monitoring equipment, much more sophisticated than what was in place in the 1980s, is continually detecting magnitude 0.5 quakes about 4 miles below the surface in the same areas where activity was detected in the years leading up to the last eruptions. Thelen noted he is confident the small earthquakes are a recent development.
