Science says: volcanoes explained
Hawaii's Kilauea is not your typical blow-the-top-off kind of volcano.
It's been simmering and bubbling for about 35 years. It has been sending super hot lava spewing up through cracks in the ground. This month's eruptions are more of the same. Except now the lava is destroying houses. The houses are miles from the summit.
Scientists on Monday said there's been a slight decrease in the pressure that forces lava to the surface. But it's likely a temporary lull. Erik Klemetti is a volcanologist. He works at Denison University. He said similar eruptions at Kilauea have simmered for years.
"It's going to take some time before you can say for sure whether things are winding down," he said.
Kilauea is the youngest volcano. It is also the most active of the five volcanoes. These are on the Big Island. It's been erupting continuously since 1983. But not the way most people think. It’s not like Mount St. Helens in 1980. That volcano spewed straight up and everywhere.
A couple of miles below Kilauea is a constantly fed "hot spot.” It has super hot molten rock. It is deep inside Earth. It needs to find a way out.
And rather than exploding, at Kilauea "you get an oozing of lava at the surface." That's according to Charles Mandeville. He is U.S. Geological Survey volcano hazards coordinator.
The molten rock is called magma when it is underground. When it reaches the surface, it is called lava. The lava flows out through cracks in the ground. Usually it flows within the confines at the national park that surrounds Kilauea (kill-ah-WAY'-ah). But this time the eruptions are destroying homes.
"This kind of eruption that is occurring now is very normal for this volcano." That's according to volcanologist Janine Krippner. She works at Concord University. It is in West Virginia. "It's really that it's just impacting people."
WHAT HAPPENED THIS TIME
The past week or so has seen "a major readjustment with the volcano's plumbing system," Mandeville said.
On April 30, scientists got their first sign something was up. The floor of the summit's lava pool had a "catastrophic failure." This forced the magma east. It was looking for ways out, Mandeville said. That created a series of small earthquakes.
The magma escaped in "fire fountains.” Lava shot as high as 230 feet (70 meters) out of cracks, Mandeville said. The first one of those happened last Thursday. It was followed by at least nine more since then.
"You don't know where the next fissure is going to open up," he said.
There's been a slight decrease in pressure. But scientists won't know for certain if Kilauea has calmed down for at least two months. That’s according to Mandeville. He said it could be much longer before conditions are safe for people to be in the area east of the volcano's summit. Officials have told some 1,700 residents to leave their homes.
The lava is 2,200 degrees (1,200 degrees Celsius), Mandeville said.
"It literally incinerates anything it touches," he said.
It's not just the molten rock. The spewed gases can be dangerous too, Klemetti said. That includes sulfur dioxide. It reacts with water in your lungs and can form acid, he said.
Mandeville said scientists want at least two months of calm before declaring the situation better.
In the meantime, "there's not much we can do other than get people out of the way," he said.
VOLCANOES MAKE HAWAII
The Hawaiian Islands only exist because of volcanoes. These volcanoes were created from "hot spots" of underground magma. They are mostly underwater. But not always. The molten rock erupts on the sea floor. It cools and forms a volcano. With each eruption, the volcano grows until it is big enough to push out of the water and form islands.
There are about 13 hot spots like this around the globe. The islands of Hawaii are one of the most active of the bunch
Nine-tenths of Kilauea's surface is less than 1,000 years old. This is quite young in geology, Krippner said.
Mandeville said there are 169 active volcanoes in the United States. This includes underneath Yellowstone. There are 1,550 in the world that are above sea level, he said.
We wouldn't exist without volcanoes, scientists said. Volcanic eruptions provide nutrients. They provide nitrogen for soil. Their gases, especially water vapor, helped form the atmosphere we now have.
"It provides so much good," Krippner said, "we just have to get out of their way while they do their thing."