Second Galapagos Eruption in June, This Time at Sierra Negra

By Erik Klemetti | June 27, 2018 9:38 am
Lava flows from the June 26, 2018 eruption of Sierra Negra in Ecuador. IG Ecuador.

Lava flows from the June 26, 2018 eruption of Sierra Negra in Ecuador. IG Ecuador.

A little less than two weeks ago, La Cumbre on Fernandina in the Galapagos erupted for the first time last September. That is no shock as the volcano has erupted 3 times since the start of the 21st century. What is surprising is that Sierra Negra on the neighboring island on Isabela erupted yesterday for the first time in 13 years. Two separate eruptions in the Galapagos in June!

The eruption at Sierra Negra so far is what we expect from shield volcanoes formed at ocean hot spots like the Galapagos: fissures and lava flows. The lava flows have quickly reached the ocean where video shows the rivers of lava created laze plumes and volcanic lightning! Pictures of the eruption (above) show some impression lava fountains coming from the fissures that opened on the flanks of the volcano. Unlike the eruption of La Cumbre, where the island is uninhabited, people live on Isabela. So far, local officials have closed the schools and shut down tourist activity on the island, as well as evacuated ~50 people. The eruption started after a brief earthquake swarm that started a few days ago.

Now, these two volcanoes are only about 65 kilometers (40 miles) apart, so it is interesting to speculate how connected these volcanoes might be. If they are anything like the volcanoes on Hawai’i, both island chains being the products of a hot spot, then they likely aren’t directly connected. Remember, in Hawai’i, Kīlauea and Mauna Loa are on top of each other, but we don’t think the two volcanoes are connected near the surface. Ultimately, they have the same deep source 100 kilometers (62 miles) down, but one volcano does not appear to trigger the other.

In other volcano news:

  • The eruption on Kīlauea keeps on going. However, the explosions at the summit appear to be weakening. The steam-and-ash plumes produced from the periodic explosions now reach in the hundreds of meters. For this reason, the aviation alert for the volcano was dropped to “orange” from “red”. This doesn’t mean that the eruption is ending, just that the threat of tall ash plumes from the summit caldera seems to be diminishing.
  • Meanwhile, a lava dome was spotting at Cleveland in Alaska. This can lead to explosive eruptions that reach tens of kilometers into the atmosphere, so the alert level there was raised to “orange” from “yellow”. These lava domes can plug the vent, building pressure until the volcano pops like champagne. Cleveland tends to see multiple explosive eruptions like this each year.
CATEGORIZED UNDER: Rocky Planet, Science, Science Blogs

Rocky Planet

Rocky Planet covers all the geologic events that made and will continue to shape our planet. From volcanoes to earthquakes to gold to oceans to other solar systems, I discuss what is intriguing and illuminating about the rocks beneath our feet and above our heads. Ever wonder what volcanoes are erupting? How tsunamis form and where? What rocks can tell us about ancient environments? How the Earth might change in the future? You'll find these answers and more on Rocky Planet.

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