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Anak Krakatoa: The dark history of volcano emerging from the sea | Indonesia News

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It was just after 9pm on Saturday when Anak Krakatoa, a volcano located in the Sunda Strait between the Indonesian islands of Java and Sumatra, erupted.

Twenty-four minutes later, a devastating tsunami struck the nearby rim of the strait, killing hundreds of unsuspected people and causing widespread destruction.

It was just the latest eruption of Anak Krakatoa, which has been active sporadically since emerging from the sea in the 1920s – more recently, it has been spewing ash and lava since June.

Experts say the tsunami, or seismic sea wave, was likely caused by the collapse of a big portion of Anak Krakatoa’s southern flank. They believe this triggered underwater landslides which displaced water to create the large killer waves.

“Underwater landside is the leading theory,” Sam Taylor-Offord, a seismologist at GNS Science in Wellington, said on Monday.

“So when that land pushes into the ocean … it displaces the ocean surface causing the vertical displacement that causes the tsunami,” he added, noting however that the lack of data and access made it impossible to ascertain this theory.

Ben van der Pluijm, an earthquake geologist and professor at the University of Michigan, also said the tsunami may have been caused by Anak Krakatoa’s partial collapse.

“Instability of the slope of an active volcano can create a rock slide that moves a large volume of water, creating local tsunami waves that can be very powerful. This is like suddenly dropping a bag of sand in a tub filled with water,” he said.





 

‘1883 explosion heard around the world’

Anak Krakatoa formed over years after the explosive eruption of the Krakatoa volcano in 1883, one of the largest and most catastrophic in recorded history.

Before 1883, the only confirmed eruption on the Krakatoa island group was a moderate one some two centuries before, in 1680.

But at 1pm on August 26, 1883, the first in a series of increasingly violent explosions sent a black cloud of ash 27km above Krakatoa.

The climax was reached at 10am the following day, with tremendous blasts that were heard some 3,500km away in Australia, ash that reached a height of 80km and a series of powerful, far-reaching tsunamis – the event was described as “the explosion heard around the world”.

Some 36,000 people were killed in Java and Sumatra in the tsunamis that followed the volcano’s collapse, with the greatest wave reaching a height of 37 metres.

‘Child of Krakatoa’

Krakatoa’s discharge sent nearly 21 cubic km of rock fragments into the air, while big large quantities of ash fell over an area of some 800,000 square km – as a result, the region surrounding the volcano was plunged into darkness for more than two days.

The dust drifted several times around the globe, creating dramatic red and orange sunsets throughout the following year. A global temperature drop was also recorded. 

A thick layer of sterile ash meanwhile covered everything on Krakatoa, and plant and animal life did not begin to reestablish itself for five years.

Krakatoa remained quiet until December 1927, when a new eruption started on the seafloor along the same line as the previous cones. In early 1928, a rising cone reached sea level, and by 1930 it had become a small island – Anak Krakatoa, or “child of Krakatoa”.

Anak Krakatoa’s cone has continuing to grow ever since, and it’s currently standing at an elevation of about 300 metres above the sea.

With the exact cause of the disaster still unknown, and Anak Krakotoa still rumbling, authorities and scientists are wary of the risk of a tsunami recurrence.

“The likelihood of further tsunamis in the Sunda Strait will remain high while Anak Krakatoa volcano is going through its current active phase because that might trigger further submarine landslides,” Richard Teeuw, of the University of Portsmouth in England, said.

Teeuw said that sonar surveys would now be needed to map the seafloor around the volcano, but “unfortunately submarine surveys typically take many months to organise and carry out,” he added.

But “devastating tsunami caused by volcanic eruptions are rare; one of the most famous (and deadly) was caused by the eruption of Krakatoa in 1883”.

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Ottawa families give mixed reviews for online schooling

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So, how’s it going with online school? Families reached by CBC Ottawa seem to have mixed reviews. 

Masuma Khan is a mother of two. Her seven-year-old, Hana Wyndham in Grade 2, is attending French immersion virtual school. Masuma is grateful it’s an option, but can’t help notice a lot of down time.

“There’s a lot of, ‘are you on mute?’ In terms of the amount of learning that’s actually happening, it does seem to be not that high,” said Masuma.

Parents who kept their children at home this fall are in the minority, but they still form a significant chunk of families in Ottawa.

In the city’s largest school board, the Ottawa-Carleton District School Board (OCDSB), about 27 per cent of elementary students and 22 per cent of high school students chose online learning. The Ottawa Catholic School Board says roughly a quarter of its students are online.

For Masuma, the decision to keep her daughter home was complex: extended family members are immunocompromised and she worried the in-person learning environment would be unpleasant because of precautions. She also felt her daughter might benefit from being supported at home.

“She doesn’t necessarily enjoy school. I also found out during the pandemic that she was being bullied [last year],” said Masuma. “So I thought, why not try from home?”

To help her daughter socialize face-to-face with other kids, Masuma enrolled Hana in Baxter Forest School, an alternative education program where kids spend most of their time outside, one day a week. Hana also attends virtual Arabic classes two days a week after school. 

Masuma’s husband and Hana share the living room work space, and Masuma admits he does the lion’s share of helping their daughter stay on task. There is a possibility that he’ll be required to return to his office in the new year.

“When he goes back to work … it’s probably going to be a little bit more difficult.”

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No school closures after Christmas holiday break, says Ontario education minister

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Ontario elementary and secondary schools will not close for an extended winter break, says Education Minister Stephen Lecce.

Closures aren’t needed given Ontario’s “strong safety protocols, low levels of (COVID-19) transmission and safety within our schools,” Lecce announced Wednesday afternoon. He said he had consulted with Chief Medical Officer of Health Dr. David Williams and the province’s public health measures advisory table.

That ended speculation about school buildings remaining closed in January for a period of time after the Christmas break.

Earlier in the week, Lecce told reporters the government was considering having students spend “some period out of class” in January, perhaps switching to online learning.

In a statement, Lecce said that even though rates of community transmission of COVID-19 are increasing, “schools have been remarkably successful at minimizing outbreaks to ensure that our kids stay safe and learning in their classrooms.”

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Windy start to the week in Ottawa

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OTTAWA — It’s a blustery Monday in the capital with wind gusts of up to 50 km/hour expected throughout the day.

Environment Canada is forecasting a high of 4 C with a 60 per cent chance of showers or flurries before the wind dies down later this evening.

There’s a chance of flurries on Tuesday as well with a high of -1 C. The overnight low will dip to an unseasonal -9 C.  

Wednesday’s high will be just -5 C with lots of sunshine.

Seasonal temperatures return for the rest of the week..

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