(KMSP) - The Hawaiian Islands have formed over millions of years of almost continuous eruptions. They formed because there is a small hole in the Pacific Plate. These plates cover the continents of the earth and generally “float” on top of the liquid rock, or magma, that encompasses the core of our planet. These plates are constantly moving, but at exceedingly slow rates, which why we don’t feel them move. Some travel just a couple millimeters a year, others travel a foot or two a year. But every time they move, we get an earthquake.
Where these plates come together however is where we have volcanoes. These are locations where the liquid hot magma can seep through cracks and rise up to the surface. But, the Hawaiian islands are different. While most volcanoes live on the edge of these plates, there is a hole, what is called a “hot spot”, in the very center of the Pacific Plate. This is how the Hawaiian Islands have formed.
The Pacific Plate slowly travels to the northwest, so if you look at the seafloor, you can see that movement based on where current and former islands are laid out across the ocean.
To complicate things a little further, every volcano isn’t the same. There are actually three types of volcanoes. The first is considered to be the classic style of volcano, or “Hollywood” volcano. These volcanoes are the ones you see in the movies that have huge eruptions that destroy everything around them in one massive explosion. A real-life version of this is Mount St. Helens. But, Kilauea is a completely different type of volcano known as a shield volcano. These eruptions have far less power to them. They typically just ooze out lava with very little steam or ash cloud associated with them. Kilauea has been erupting like this for over three decades. But, why are scientists suddenly expecting explosive eruptions? It all has to do with blockages.
Shield volcanoes are usually less explosive because the magma chamber, the vent that the lava moves up through, is free of rock and other debris. This allows the lava to flow out easily and allows the gases created by the lava to escape without trouble. But when debris gets in the way, suddenly the gases and lava get stuck. Well with lava continuing to pour up from the center of the Earth, immense pressure begins to build up until the blockage is released in a massive explosion. Think of it like a freeway. Normally traffic flows freely, but when there is an accident of some kind, traffic comes to a halt and then begins to build up over time. Eventually the crash is cleared and then those cars stuck for a while surge ahead in one massive group. This is essentially what happens with volcanoes.
At the moment, the lake of lava in the current erupting crater is falling because this lava is seeping out through cracks, called vents, on other parts of the island. Because of this, the now cooled sides of the tube are now starting to fall into the lava lake down below, instantly pulverizing this rock and sending clouds of smoke and ash into the sky. IF the lake continues to fall, it becomes increasingly likely that the sides of this lake will collapsed inward which would likely cause a large explosion to envelope much of Volcanoes National Park on the eastern side of the island. While the whole island will likely not be affected, parts of the eastern side could see some devastating results if this were to happen. Unfortunately, all we can do as wait and see.