There remains but a third of the Anak Krakatau volcano in Indonesia, after a series of eruptions and a collapsed sidewall, a deadly tsunami it caused.
The height of the volcano is, according to the Volcanology and Geological Hazard Mitigation centre with 200 metres decreased. Before the eruption, he was 338 meters high, now the volcano is just 110 metres high. The eruptions also made the mass of the volcano decreased from 180 million cubic metres to 40 to 70 million cubic metres.
The contraction reduces the risk of a new landslide that a tsunami can cause, said Antonius Ratdomopurbo, secretary of the department of geology of the Indonesian ministry of energy. The Indonesian authorities have the no-go zone around the volcano, however, expanded by five kilometres.
The Anak Krakatau had the past months been incessantly ash and lava into the air, spitting. Last weekend, broke a 64 acre portion of the southwest vulkaanwand that then into the sea collapsed. “That caused a landslide on the seabed, that led to a tsunami,” says Dwikorita Karnawati, head of the meteorological service of Indonesia. “That tsunami reached 24 minutes later, the coast.’
There was no tsunamialarm, because the existing equipment was not able the signals to measure. There was no earthquake or the existence of a retreating sea. As a result, the beachgoers surprised by the rising water. There were more than 400 people dead and thousands injured.
The 17,000 islands of Indonesia are situated on the so-called ‘Ring of Fire’, the geologically most active zone in the world. It is a horseshoe-shaped strip of about 40,000 kilometers along New Zealand, Papua New Guinea, Indonesia, the Philippines, Japan, Alaska, Canada, the United States, Mexico, and South America. The vast majority of the world’s earthquakes, almost all of the largest earthquakes and approximately 75 percent of the volcanic eruptions – hence the name Ring of Fire – find place.