Why do volcanic eruptions happen in Hawaii?
The Kilauea eruption
On May 3rd, 2018, around 4:30 pm the Leilani Estates subdivision on The Big Island of Hawaii developed fissures in the ground around 2.5 mile long and plumes of smoke started coming out. The next day witnessed a 6.9 magnitude earthquake followed by the Kilauea volcano spewing out molten lava covering 116 acres and destroying over 36 structures. Since then, the island has been witnessing regular eruptions of lava and toxic sulfur dioxide gas reaching up to 125 feet in the air.
The residents of the island have been forced to evacuate the southern side as molten lava began to flow through the residential areas. Lava has been steadily flowing out and spreading out towards the Pacific Ocean where the molten rock flow has been entering the water.
The Island’s big worries
Volcanic activity results in hot lava flowing out where temperatures can easily touch 2,000 degrees Fahrenheit (1,093 degrees Celsius). Besides the heat generated, acid rain, sulfur dioxide gases are major threats to human life and the environment.
Vog is formed when sulfur dioxide and other gases released mix with oxygen and moisture in the air during the daytime. The resulting sulfuric acid and sulfates produced are hazardous to human life.
The Kilauea volcano is the most active volcano in Hawaii and has been continuously spewing lava since 1983. Vog has been a natural outcome with each eruption. The Kilauea has been releasing vog from three outlets; PuuŌō vent, Halemumau crater, and along the coastline of the East Rift Zone where the lava enters the seawaters.
But the latest worry is the ‘laze,’ the toxic mixture of lava and haze combines to produce hydrochloric acid fumes, steam, and fine volcanic glass specks as the lava enters sea waters.
The current eruptions have resulted in laze extending over 16 miles along the coast and offshore. Warnings have been given out to stay away from the rising plumes of toxic laze, which have a PH level between 1.5 and 3.5. The damage caused is similar to what dilute battery acid can cause.
Volcanic activity around the world
The planet has over 1,500 active volcanoes, and about 500 have been erupting since human life inhabited the earth. North America is home to 169 active volcanoes spread across Hawaii, California, Washington, Wyoming, and Alaska.
The deep crust of the earth contains hot molten rocks called magma. The movement of tectonic plates often collides with one another and sometimes climbs over the other at the edges with one plate rising from one end and the other pressing lower in a process is called subduction.
Subduction results in fissures called Hot Spots from where molten lava flows out in the form of a volcano. Earthquakes can precede or accompany a volcanic eruption. As the plate moves away, the easing pressure closes existing fissures and opens up new channels for lava to flow out.
The perimeter of the Pacific Tectonic Plate known as the ‘Ring of Fire’ extends 25,000 miles running from Southeast Asia towards Russia, Alaska and then onto South America. Over ninety percent of all earthquakes and seventy-five percent of volcanoes have occurred along the Ring of Fire.
Why do volcanic eruptions occur in Hawaii?
Hawaii lies on the Pacific Plate and part of the Ring of Fire. It is the largest single tectonic plate covering the Pacific Ocean surface. The moving plate lies over the earth layer called Asthenosphere and has been moving northwestwards at the rate of 5 to 10 cm/year.
The Hawaiian Island were formed out of basalt rock (tholeiite) that comes out of volcanic activity as molten lava. As the rock dries out life occurs on the land, a process that can take several thousands of years. In fact, 80 percent of the earth’s surface has been formed out of volcanic eruptions.
The Big Island is made up of five volcanoes – Mauna Loa, the world’s largest active volcano, last erupted in 1984; Kilauea, the current and most active volcano on earth erupting since 1983; Hualalai, last erupted in 1801; Mauna Kea, last erupted around 4,000 years ago; and Kohala.
Hawaiian volcanoes are shield volcanoes – molten lava flows out of gentle slopes rather than exploding eruptions as seen in Iceland in 2010. Shield volcanoes spewing out molten basalt rock have formed all of Hawaii. The more explosive volcanoes in other parts of the planet flow out of steeper slopes resembling conical volcanoes.
The Hawaiian Archipelago chain of volcanoes extends from the youngest ones concentrated at Loihi in the southeastern end of the volcanic chain extending to Kure, which represent the oldest volcanoes.
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