Then and now: The photographs of the Japanese satellite ALOS-2 on August 20 (left) and December 24 show how the volcano Anak Krakatau has changed. (Photo by Japan Aerospace Exploration Agency on EPA-EFE)
JAKARTA: The volcanic island of Anak Krakatau, which broke and collapsed a week ago, triggering a deadly tsunami, is now less than a third of its size before the eruption. Scientists say.
The Indonesian Center for Volcanology and Geological Disaster Reduction says that Anak Krakatau now has a volume of 40 to 70 million cubic meters, compared with about 1
The analysis shows the scale The collapse of the island sheds light on the power of the tsunami, which affected more than 300 kilometers of coast in Sumatra and Java. More than 420 people died.
According to the center, the crater was 110 meters high on Friday, compared to 338 meters in September.
The volcano's shrinkage in height and size reduces the risk of another landslide leading to a landslide Tsunami, Antonius Ratdomopurbo, secretary of the Department of Energy's Department of Energy, told reporters in Jakarta on Saturday.
The current eruptions of Mount Anak Krakatau are described as Surtseyan, as the lava from the crater contacts seawater, he said. The word comes from Surtsey, a volcanic island that formed in 1963 off Iceland in the sea.
"Given the low volume of Anak Krakatau, it is unlikely that we will see a large landslide triggering a tsunami." Ratdomopurbo said. "A tsunami could only happen if a fault reactivation takes place in the Sunda Strait."
The Indonesian authorities have extended a no-go zone around the volcano to five kilometers, and have ordered airlines to avoid the airspace over Anak Krakatau from ash clouds, were seen up to 24,000 feet above sea level this week ,
The deadly tsunami on Sunda Street on December 22 killed at least 426 people and injured more than 7,000 residents and vacationers in the provinces of Lampung and Banten.
The killer wave was probably triggered by a flank collapse followed by a section of the volcano on the south and southwest sides of Mount Anak Krakatau, according to Indonesian geologists. The volcano will grow because the crater still contains magma that can trigger volcanic activity, said Ratdomopurbo.
"I would expect the shape of the island to change dramatically over the next few days, weeks and even months," said Thomas Giachetti, a volcanologist at the University of Oregon, in an email. "It will enter a phase of construction and destruction until the cone is again high enough to prevent significant mixing of the magma with external water and the eruptions, to return to a more Strombolian type."
"It is possible that the new form of The volcano also allows a slow movement of volcanic material into the sea and into the caldera formed by the eruption of 1883. "
Indonesia's 17,000 islands are prone to earthquakes as the country spans the Pacific Ring of Fire – an arc of fault lines and volcanoes that cause frequent seismic upheavals. Two of the biggest eruptions of the last 200 years took place in Indonesia on Mount Tambora in 1815 and in Krakatau in 1883. An eruption of Mount Kelud in 1919 killed more than 5,000 people.
In September of this year, more than 2,000 people were killed in Central Sulawesi after a devastating earthquake and tsunami on the island and displaced about 80,000 people. This was preceded by a series of deadly earthquakes in early 2018 that shook the popular tourist destination of Lombok east of Bali.