Anak Krakatau, Indonesia - December 2018

Background Information

• Population approx 238 million (2018)

• Capital city Jakarta (not affected by the earthquake)

• Archipelago of volcanic islands located in the Pacific Ocean in east Asia

• One of the MINT countries with a rapidly expanding economy (and population)

• High degree of vulnerability despite awareness of tectonic risk

• Emotional attachment to their country - belief that volcanoes and earthquakes are retribution for behaviour of people

• 23rd December 2018 - 21:00 (tsunami) - eruption continued for approx 1 week

Cause

• Located on Pacific Ring of Fire

• Constant risk of natural disasters - tsunamic, volcanic eruptions, earthquakes

• Volcano lies in the Sunda Strait - site of Kratatoa (erupted in 1883 - most destructive volcano ever - power of 4 nuclear bombs - causing volcanic winter)

• Between Java and Sumatra - linking Indian Ocean and the Java Sea on subduction plate boundary

• Tsunami - triggered by eruption of Anak Krakatoa (child of Krakatoa, formed 44 years after original eruption) - set off undersea landslide - 64 cubic hectare side (flank) of volcano collapsed into sea

Effects

• Large tsunami swept into coastal towns on Indonesian islands of Sumatra and Java

• Approx 429 people died - many deaths at a rock concert held on Tanjung Lesung beach

• 150 still missing

• Approx 1,400 injured

• Approx 556 houses, 9 hotels, 60 food stalls, and 350 boats known to have been damaged

• 16,000 people displaced

• Thousands of people living in temporary shelters - e.g., mosques or schools - dozens sleeping on floor

• Volcanic cone (340m high) - now only 110m tall

• 150-170 million cubic meters of material gone - 40-70 million cubic meters still in place

• Torrential rain followed eruption - slowed down emergency aid and rescue operations

Mitigation

• Volcanic tsunamis may not trigger warning systems

• Took 23 minutes for tsunami to reach land after volcano erupted

• Warning times would have been minimal given high speeds tsunami waves travel

Responses

• Aid agencies (NGO’s) supported evacuation of injured - provided clean water, shelter, and tarpaulins

• Volunteer groups cooked meals for people who were displaced/emergency camps

Wider Reading

• Tsunami crashed into more than 300km of coastline in Sumatra and Java

• 23 people missing in waves that were 2 meters or higher

• Experts largely relied on satellite radar images to work out what happened to the volcano due to cloud cover + continuing eruptions

• High seas have hampered inspections

• Residents warned to stay away from coastline of Sundra Strait because of the risk of another tsunami

• Another potential tsunami triggered by volcano collapsing again would be less severe due to its reduced mass

• Torrential rain complicated recovery aid efforts, muddying roads and holding up convoys delivering heavy machinery and food to remote areas

• Third major natural disaster in just a few months