Indonesia Anak Krakatau Erupts: Tsunami Kills 222
Mount Anak Krakatau located in Sunda Strait, South Lampung, erupted for 156 times since Tuesday, October 2 until early Wednesday. The eruption followed by incandescent lava and thunder sounds, and a tsunami wave.
At least 222 people are dead, over 800 injured, and many more are missing, after a tsunami struck Indonesia late Saturday night local time. Officials there are blaming the tsunami on underwater landslides caused by volcanic activity on the island of Anak Krakatau, which erupted just after 9 p.m.
Stop Purwo Nugroho from Indonesia’s disaster management agency said that 556 houses , nine hotels, 60 culinary stalls and 350 boats were known to have been damaged.
Indonesian rock band Seventeen were midway through their performance in a tent at Tanjung Lesung beach resort in west Have when the wave hit the stage, dragging the musicians and audience members with it. The band’s bassist and road manager both died. Four other band members are missing.
Sutopo Purwo Nugroho, Head of the Information Data Center and Public Relations of the National Disaster Management Agency (BNPB) said that on Sunday the volcano located in the Sunda Strait, Lampung Province, had been erupted almost every day.
Mount Anak Krakatau’s Observation Post, Volcanology Center and Geological Disaster Mitigation (PVMBG) reported that there were 576 eruptions during the day on Saturday, August 18. The eruption height varies, 100 meters to 500 meters from the top of the crater.
On Saturday at 6:09 pm, an eruption occurred with an ash column, about 500 m above the peak (about 805 m above sea level). The black ash column with thick intensity was inclined towards the north. The eruption was recorded on a seismogram with a maximum amplitude of 42 mm and a duration of 2 minutes 33 seconds.
This is the second largest eruption since 18 June 2018. The most eruption had 745 eruptions on 30 June 2018. The eruption that occurred this time was small but successive, had no effect on the flight route and shipping lanes in the Sunda Strait.
The followings are five facts of Mount Anak Krakatau.
1. Brief History
Mount Anak Krakatau emerged from the sea on June 11, 1930, due to magmatic activity inside the caldera of Mount Krakatoa enormous eruption in 1883. In 2000, the volcanic mountain grew up to 300 meters above the sea level, and in October 2018, the height reached 338 meters.
2. Warning Status
The PVMBG issued the warning status (Alert Level 2) on Mount Anak Krakatau since 2012. “[Which means] the mountain activity may increase; it may erupt or not, or eruption may occur in the crater area,” said Devy Kamil Syahbana, the PVMBG official, in June 2018.
3. The color of column ash always changes
A vulcanologist from Bandung Institute of Technology, Mirzam Abdurrachman, explained the color of the volcanic ash of Mount Anak Krakatau varies, for example in August, the dark column ash changed into light color.
Meanwhile, based on observation conducted by PVMBG officers as noted in Magma Indonesia website, the column ash was in light color with thin intensity and as high as 50 meters from the mountain crater. In the night, the column ash showed firelights.
Mirzam explained the color changes–called as ultravulcanian in vulcanology term– described the mountain process.
4. Variety of lava colors
The color of the lava flown from the mountain crater also diverse, such as red, yellowish red, yellow, and white. The bright orange lava means its temperature was at 1,000-1,050 degree Celsius, red at 800-1,000 degree Celsius, dark red at 650-800 degree Celsius, and brownish red at 500-650 degree Celsius.
5. The mountain keeps growing
The PVMBG official Wawan Irawan explained the eruption of Mount Anak Krakatau marked it was in a growing phase.
According to Wawan, Mount Anak Krakatau grew by around 4 meters per year. “But, it does not erupt every year,” he said Monday, August 20. As of August 2018, the island diameter of Mount Krakatau reached 2 kilometers. The eruption that often occurs is strombolian eruptions which eject materials from the mountain (such as incandescent cinder, lapilli, and lava bombs).
The material ejection due to Mount Anak Krakatau eruption was usually found outside the coastal border of the volcanic mountain island. Therefore, the safety zone set at 2 kilometers away from the mountain, from previously at 1 kilometer.