Born from volcanoes, Hawaii is a place where spectacular beauty stems from intense geophysical forces that have operated over millions of years.
What’s Behind Kilauea Volcano’s Eruption This Spring?
The outer envelope of the Earth is made up of various rigid and constantly moving “plates”.
Plate movement results in earthquakes and volcanoes – mostly near boundaries where plates push and rub against each other.
Volcanoes and earthquakes often create new landforms, such as mountains and ocean trenches.
If you imagined the Earth as an orange, the crust is like a very thin part of the skin.
Beneath the hard layer of rock is a layer called the mantle. This is the area of earth just above the core. The mantle is made of minerals, denser than what’s in the crust, said Erik Klemetti, volcanologist, blogger and associate professor at Denison University in Ohio.
A hotspot is the point where a plume of magma – molten rock – protrudes from upper levels of the crust. The plate sits on the outermost layer of the crust and moves over the hot spot. And then what happens?
The hotspot – essentially, a pressure button in Earth’s mantle – erupts and produces magma, which rises and crosses the surface to form volcanoes.
Once the resulting lava cools, it is essentially new land.
It can be quite fertile and make great agricultural land.
But it can have an unfortunate impact on people who live in the shadow of a volcano. As of Tuesday, 35 structures – including at least 26 homes – had been destroyed in Kilauea’s eruption.
“It’s potentially one of those disasters that’s been going on for a long time,” Klemetti said.
For the Western Hawaiian Islands, the action took place millions of years ago. Their volcanoes are asleep.
And while they’re still incredibly beautiful, there’s just a little less to enjoy.
This is because waves, winds, landslides and erosion have since taken their toll.
Because the Big Island is younger and growing, these forces haven’t reduced much of it.
The Big Island has at least four active volcanoes, Kilauea in the lead.
“Mauna Loa has erupted 33 times since 1843, with the most recent eruption in 1984,” reports the US Geological Survey. “Loihi, the underwater volcano located off the south coast of Kilauea, most recently erupted in 1996.”
Hualalai has erupted three times in 1000 years.
Kilauea, the youngest and busiest on the island, likes to make the news.
It has been erupting almost continuously along its east rift zone since 1983, according to the US Geological Survey.
The result was a whole pile of lava that poured into the Pacific Ocean.
Klemetti, who visited the island in 2013, said it might take some time for the flow from this eruption to reach the water. For now, “It only makes the island higher.”