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Threat of powerful eruption at Kuchinoerabu volcano prompts evacuations, Japan
The Japan Meteorological Agency raised the alert level for the Kuchinoerabu volcano in Kagoshima Prefecture from 2 to second highest level of 4 at 01:30 UTC (10:30 JST) on Wednesday, August 15, 2018. This volcano is located on the Kuchinoerabu Island in southwestern Japan, some 1 000 km (620 miles) SW of Tokyo. Its last eruption took place in 2015. The decision to raise the alert was made due to 26 volcanic earthquakes detected within just a few hours. The largest was M1.9 at a depth of 5 km (3.1 miles) in almost the same location as a similar pre-eruption quake that struck 3 years ago. JMA warned that eruption could be powerful enough to cause serious damage to the island's residential area. Level 4 alert means that elderly and disabled people should be evacuated and everyone else should prepare to evacuate. This is the first such warning for this volcano since May 2015 when a powerful eruption forced …

1.7-billion-year-old chunk of North America found sticking to Australia

This diagram shows the Georgetown terrane, in green, joining Australia around 1.6 billion years ago during the formation of the supercontinent Nuna. (Credit: Geology, https://doi.org/10.1130/G39980.1)

Geologists matching rocks from opposite sides of the globe have found that part of Australia was once attached to North America 1.7 billion years ago.
Researchers from Curtin University in Australia examined rocks from the Georgetown region of northern Queensland. The rocks — sandstone sedimentary rocks that formed in a shallow sea — had signatures that were unknown in Australia but strongly resembled rocks that can be seen in present-day Canada.
The researchers, who described their findings online Jan. 17 in the journal Geology, concluded that the Georgetown area broke away from North America 1.7 billion years ago. Then, 100 million years later, this landmass collided with what is now northern Australia, at the Mount Isa region. [Photo Timeline: How the Earth Formed]
"This was a critical part of global continental reorganization when almost all continents on Earth assembled to form the supercontinent called Nuna," Adam Nordsvan, Curtin University doctoral student and lead author of the study, said in a statement.
Nordsvan added that Nuna then broke apart some 300 million years later, with the Georgetown area stuck to Australia as the North American landmass drifted away.
The continents as we know them today have shifted places throughout Earth's 4-billion-year history. Most recently, these landmasses came together to form the supercontinent known as Pangaea about 300 million years ago. Geologists are still trying to reconstruct how even earlier supercontinents assembled and broke apart before Pangaea. Scientists first proposed the existence of Nuna, Earth's first supercontinent, in 2002. Nuna is sometimes called Columbia.
Previous research suggested that northeast Australia was near North America, Siberia or North China when the continents came together to form Nuna, Nordsvan and colleagues noted, but scientists had yet to find solid evidence of this relationship.
Colliding landmasses can form mountain ranges. For example, the clash of the continental plates of India and Asia about 55 million years ago created the Himalayas. The researchers of the new study say they found evidence of mountains forming when Georgetown rammed into the rest of Australia.
"Ongoing research by our team shows that this mountain belt, in contrast to the Himalayas, would not have been very high, suggesting the final continental assembling process that led to the formation of the supercontinent Nuna was not a hard collision like India's recent collision with Asia,"Zheng-Xiang Li, a co-author of the study and a professor of Earth science at Curtin University, said in the statement.

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