natural disaster
After volcanic eruption off Tonga: What is the situation?
After the volcanic eruption. Photo: Consulate Of The Kingdom Of Tong/ZUMA Press Wire/dpa
© dpa-infocom GmbH
Destructive eruptions from undersea volcanoes like the one off Tonga are rare. The eruption in the Pacific not only caught people on the islands unprepared – experts are also baffled.
About a week ago, the submarine volcano Hunga-Tonga-Hunga-Ha’apai shook the Pacific with a deafening bang and an ash cloud 20 kilometers high.
According to the government of Tonga, the eruption triggered a tsunami up to 15 meters high, which caused severe destruction in the South Pacific state and killed at least three people. Communication with the islands broke down as a result of the volcanic eruption. Questions and answers on the situation in the region.
How big is the damage?
An estimated 84 percent of the approximately 105,000 residents on all islands were affected by the ash rain and the tsunami, the government said recently.
Especially near the coast, the destruction is enormous. Videos shot on land were released on Friday, showing the extent of the disaster. The tsunami leveled numerous houses, uprooted trees and devastated entire regions. The west coast of the main island of Tongatapu, where there are many hotels, has also been badly affected, as the New Zealand High Commissioner in the archipelago, Peter Lund, said recently.
The normally colorful South Seas islands are covered in a pale layer of ash. Observers speak of a “lunar landscape”. Footage released on Saturday showed residents amidst rubble and fallen trees on Mango Island, home to around 36 residents, where all the houses have been destroyed.
Is communication possible again?
Only partially. According to the government, communication between the islands remains “an acute challenge”. At least some of the international telephone lines have been restored. Relatives abroad who had had no information from their families in Tonga for days were finally able to reach their loved ones.
However, a vital undersea cable that carries almost all digital information, including Internet and telephone communications, has broken in two places. According to US cable company SubCom, it will take at least four weeks to repair the cable connection. According to Tonga’s government, a ship is due to arrive in Tonga in the coming days to begin repair work. A relief flight from New Zealand brought much-needed telecommunications equipment to restore limited internet connectivity.
The international mobile phone provider Digicel has set up a bridging system via satellite on the main island of Tongatapu. However, the connections are “limited and patchy,” it said.
Even volcanologists cannot predict whether the Hunga-Tonga-Hunga-Ha’apai will now rest. “The only thing we can say for sure is that the volcano has now erupted. So the probability is low that there is much more magma underneath, »said geochemist Oliver Nebel from the renowned Monash University in Melbourne. However, that is not a guarantee: in the past, volcanoes have erupted violently several times in a row. Experts are also wondering what is left of the previously 1,800 meter high and 20 kilometer wide submarine fire mountain. An island that was only created in 2015 during a months-long eruption of the volcano has disappeared completely, as satellite images show.
How common are such violent eruptions from undersea volcanoes?
According to experts, such a gigantic eruption of the Hunga-Tonga-Hunga-Ha’apai only occurs about every 1000 years. It was also the world’s most violent volcanic eruption since the eruption of Pinatubo in the Philippines 30 years ago, which happened on land at the time. There are numerous undersea volcanoes along the Pacific Ring of Fire, but most of them are at great depths. When they break out, it is usually hardly noticed. The caldera (cauldron) of the Hunga-Tonga-Hunga-Ha’apai, on the other hand, was just below the surface of the water.
Tsunamis are usually triggered by seaquakes – only rarely by submarine volcanoes. According to New Zealand researcher Emily Lane, it was the first volcanic-triggered Pacific-wide tsunami since Indonesia’s devastating 1883 eruption of Krakatoa, which killed 36,000 people.
What is most urgently needed in Tonga?
Drinking water is the most urgent need right now, as the ash has polluted Tonga’s rainwater and boreholes from which people get their drinking water. According to the government, almost 60,000 liters of water have been distributed as part of the relief measures. The New Zealand government ship HMNZS Aotearoa, which can transport 250,000 liters and produce 70,000 liters per day through a desalination plant, arrived on Friday.
Food, temporary accommodation, medical equipment and hygiene items are also needed. The first aid deliveries from New Zealand and Australia have now arrived in Tonga. Although there has been no further volcanic activity to date, sea transport remains difficult as ash on the sea surface damages ships. The EU and Great Britain also want to send aid to Tonga.