How a tsunami hit Indonesia again, could surprise

d45e9d42b43d75e33cff9a1079c5bf26 - How a tsunami hit Indonesia again, could surprise

The tsunami in the weekend at least 281 Indonesians killed, was indeed caused by a volcanic eruption, so confirm scientists Monday. And just as a result, there is no alarm.

The dozens of people who eventually the victim would be out of the tsunami that Saturday the coasts of the islands of Java and Sumatra, and found, to the Straits of Sunda, had not the slightest idea that …

The dozens of people who eventually the victim would be out of the tsunami that Saturday the coasts of the islands of Java and Sumatra, and found, to the Straits of Sunda, had not the slightest idea that there are huge waves on them did not sink. Waves that were caused by the eruption of Anak Krakatoa, the ‘child’ of the Krakatoa volcano, so it is now confirmed.

The Anak Krakatau had the past months been incessantly ash and lava into the air, spitting. Last weekend, however, broke a 64 acre portion of the southwest vulkaanwand that then into the sea collapsed.

“That caused a landslide on the seabed, which then led to a tsunami,” says Dwikorita Karnawati, head of the meteorological service of Indonesia. “That tsunami reached 24 minutes later, the coast.’ With the catastrophic consequences.

No tsunamialarm

Satellite images taken by the Sentinel-1 satellite of the European space agency (ESA) confirm the reading of the Indonesian authorities. That is to see that a large part of the southern vulkaanwand indeed in the sea is deposited.

‘A landmass of that size to move the surface of the ocean, and causes the vertical movement of a tsunami in my part, ” says the New Zealand seismoloog Sam Taylor-Offord against news agency Reuters.

But had Indonesia after the december 2004 tsunami, which spread across fourteen countries less than 226.000 lives, not invested in an ‘early warning’ system for tsunamis? Yes, but that warning system gave Saturday is not at home. “The initial volcanic eruption and all the natural disasters that accompanied it, ensured that the subsequent landslide not struck on the measuring equipment that the tectonic activity in the keep an eye on’ suspects Taylor-Offord. ‘There was no earthquake. That has all led to the fact that there is no tsunamialarm is promulgated.’

Waves up to three metres

Also residents of the affected coastal plain to say that shortly before the tsunami, no signal saw that pointed to the rising waves of up to three metres high. So had no earthquake or receding water on the beaches are seen.

“The knowledge about tsunamis that follow an earthquake is much limited than that about tsunamis after an earthquake,” says kustingenieur Jose Borrero, specializing in the study of tsunamis. “There are so many different variables that determine whether a landslide on the seabed, then a tsunami caused. The land area must, for example, are just big enough and at the right speed, the sea collapse, a wave can arise.’

Thousands of sensors are needed

It is not the first time that the Indonesian tsunamialarm fails to appear. In a flood a few months ago on Sulawesi failed the alarm even though. That was caused by an earthquake, a 7.9 on the Richter scale. More than 2,000 people perished. There were also 170 aftershocks, that the reddingswerken hampered. Volunteers on site were forced to bodies in mass graves to bury.

“Even when there was outrage about the lack of an early warning system,” says professor Simon Boxall of the National Oceanography Centre in Southampton to The Guardian. “But a lot of tsunami’s store very locally. To the Indian Ocean to map with sufficient sensors would you many thousands of buoys with sensors are needed.”

Nevertheless, the Indonesian president Either Widodo Monday, the national geological institute dedicated to better equipment to purchase for the existing warning system. “The tsunami that our Saturday has struck, we were able to with our current equipment cannot measure. Normally there is first a earthquake. That was not the case now, making the victims on many of the beaches are aware of no evil’, says the head of state.

Ring of Fire

The geological institute release to news channel CNN to know that it is now to think about the placement of special cantilevered flood walls. That need to the formation of high waves off the coast can detect, even if there is not first an earthquake took place.

The question remains whether that will be sufficient. Indonesia is 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 – finding there place.

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