Almost everyone has heard of the term volcano but only a few people have heard of supervolcanoes. According to the beliefs of scientists, supervolcanoes are spread just the same as normal volcanoes. Several supervolcanoes have been found until now. Caldera and supervolcano in America’s Yellowstone national park prove the above fact. Super volcanoes are the supervillains in the whole volcanic world. There are several common misconceptions about these supervolcanoes. No matter how many volcanoes are out there only a few volcanoes are super volcanoes out of them.
According to the Volcanic Explosivity index, explosions that happen in the range of 8 magnitudes can be called supervolcanoes.8 magnitudes means the highest value in VEI. The meaning of this is in such type of eruption, material is exploded and released for more than 1000 cubic kilometers (240 cubic miles). Volcano Explosivity Index (VEI) is an index created by scientists to measure the explosiveness of volcanic eruptions. This is an approximate measurement unit. The word “Supervolcano” first came into use in the 1940s but by 2000 the word was quite popular. Even though this word is not a scientific term, currently, scientific communities have accepted this term. In a super volcanic eruption, a certain amount of magma comes out and forms a circular-shaped collapse feature above the magma storage area. this can be called a collapsed volcano.
Just like the term super volcanoes there’s a term called super eruptions. Caldera is created from some of those eruptions only. In such cases, a large area is covered with lava and volcanic ash, and this could result in a long-term weather change in and around that area. Magma is a molten or semi-molten liquid inside the earth’s crust. This is a natural fluid. All igneous rocks are created by this magma. From the last, 2 million years caldera has been created in several volcanoes. Some examples of such volcanoes are Long Valley in eastern California, Toba in Indonesia, Valles caldera in New Mexico & Taupo in New Zealand.
Eruption in supervolcanoes is much larger than normal volcanic eruptions. And the scale of those eruptions is larger. These are not like cone-shaped composite volcanoes. It’s because they don’t have a huge slope like them. therefore, observing this is done from the upper sky (space). Because Caldera is large in scale a good observation can be done from space.L
Yellowstone national park which spans to Montana, Idaho, and Wyoming states is a large volcano. This can be also called a Yellowstone supervolcano. This hasn’t been activated from 70,000 years. This is right under Yellowstone national park while Yellowstone caldera is located northwestern in Wyoming. Yellowstone caldera has been formed by three super-eruptions that occurred in the last 2.1 million years.
This caldera is under the Yellowstone plateau, A super eruption occurred approximately 640,000 years ago. Anaheim hotspot under the North American tectonic plate is an example of a volcanic hotspot. Even though these surfaces seem flat, they are deeper than the hotspot’s surrounding area. And the north American tectonic plate movement doesn’t affect this. Scientists predict that in the last 16.5 million years 15-20 eruptions have occurred in the Yellowstone hotspot. According to them, the molten rocks, lava and ash amount produced and created from the super-eruption which succeed in creating a caldera was enough to fill the Grand Canyon.
The current activities in Yellowstone supervolcano are only limited to hot springs and geysers. Geysers are like tubes that travel water beneath the earth’s surface. The end of these tubes has molten rocks which are known as magma. Hence the water inside this tube gets warm. The heated warm water is then periodically stirred up under high pressure. This is a simple process in geysers.
The 30-meter-high geyser in Yellowstone national park is called old faithful Geyser. This releases about 3700 gallons of water into the upper air every single 91-minute period. These activities in Yellowstone Yosemite are caused by the plume of magma below the Yellowstone caldera. It is believed that the last time when lava flowed after a magmatic eruption in Yellowstone supervolcano was 70,000 years ago.
The most recent three eruptions occurred around 700,000 years ago. These are based on the durations of two eruptions, and this is not a correct method of predicting future eruptions. Supervolcano at Yellowstone is not a single volcano it is a volcanic system. super-eruptions do not occur in a specific period of time and cannot be predicted. Simply there’s a possibility of a super eruption occurring in Yellowstone supervolcano, but we cannot exactly say when from the column, 6-8 % contains magma, and the rest column around 92-94 % is hardened but still warm. According to the belief of the scientists the percentage of magma beneath the volcanic caldera is not strong enough to make a super eruption.
But it remains unclear and doubtful whether there’s that much magma beneath the caldera. In order to observe the changes, Yellowstone volcano observatory (YVO) was established. YVO scientists have placed 26 seismic stations, 16 GPS receivers, 11 gauging stations around Yellowstone volcano. Any volcano that erupts gives signs. Either it’s weeks or months before the eruption. All volcanoes give off signals weeks or months before they are about to erupt. A Yellowstone supervolcano takes longer than a normal volcano to do so. This dormant Yellowstone supervolcano does not have a wake eruption in a day. It will take a lot of time. But we are slowly approaching the time when the Yellowstone supervolcano will have a super-eruption. It is not possible to specify exactly when and how much damage those super-eruptions will cause.
Even though the super-eruptions in super volcanoes are devastating this could not lead to the world’s end. The hot ashes and gas emitted from this kind of eruption could spread to miles and miles in the atmosphere and this could lead to various weather conditions. The storms which are known as pyroclastic flows occur as a result of such weather conditions. Because of the hot ashes and gas in the atmosphere, the sky around that area gets dark and as a result, till several years pass summertime doesn’t arrive in the erupted areas.
A recent example of such a situation occurred in 1816. North America and Europe had to face “A year without a summer”. The mega eruption occurred in 1815 in Indonesia, Tambora is the reason for this. The dirt particles and ash particles could cause breathing issues to people and even cause death, and this could spread over 100s of kilometers. This kind of super eruption results both locally and globally.
Yellowstone is not the only supervolcano in the world in fact there are several other volcanoes, but the most known super volcano is this.
Last approximate time this volcano got erupted was 1800 years ago. But the first eruption has taken place 300,000 years ago. At present these volcanic areas are covered with Taupo Lake in New Zealand. Taupo is not a large volcano, but several super-eruptions and eruptions occurred in the area resulting in the creation of a caldera. For a small time period, this caldera is filled with water. Taupo super eruption is one of the most disastrous eruptions in recent history. It is spread over more than 20.000kms areas.
This is a giant super volcano located in eastern California near mammoth mountain. This is one of the largest calderas in earth. It is 29km(20mile) long and 18 km (11 miles) wide and the depth has extended up to 910km (310ft). This long valley caldera was created as a result of an eruption occurred 760,000 years ago. Long valley super volcano is a bit special than normal super volcanoes. That is because this consist of both basaltic and silicic lava.
Even though this is a supervolcano this is currently a lake in Sumatra, Indonesia. This Toba Lake is 100km (62 miles) long and 30 km wide (19 miles). And the depth of this lake is about 505 meters (1057 ft). Toba lake is the largest lake in Indonesia and the largest volcanic lake in the world. In 2020, Toba caldera was accepted as a UNESCO Global Geopark. A super eruption of 8 magnitudes in the VEI index occurred in this lake before 74,000 years. This is the largest known explosive eruption in the past 25 million years. After the explosion world’s temperature dropped and a winter season of to Celcius started.
The Toba super-eruption occurred 74,000 years ago in this same Toba Lake. The last super eruption estimated 8 magnitudes in VEI resulted in a 6-inch ash layer covering the whole of Asia because of the subsequent collapse this area was covered by water and it was believed that this lake was formed gradually after that.