a Little time? At the end of text there is a summary.
The people in the early evening of the 28. September on the Parking deck of the Grand Mall of Palu, you have fear. A first shaft is rolled already. And now, a white-gray wall of water. Approaching over the Bay, is incredibly fast larger. One pulls out his cell phone and filmed.
It will only take moments until the coast is buried under meters high water. Hundreds of people will die, including on the nearby beach, Talise, where a music festival is celebrated. The people on the Parking deck to get panic, you race. It’s too late – but after all, they are increased. This can save your life.
Detik-detik saat tsunami menerjang Pantai Palu pada 28/9/2018 sore pascagempa 7,7 SR mengguncang Dong gala. Tinggi tsunami sekitar 3 meters. Permukiman di sekitar pantai hancur disapu tsunami. pic.twitter.com/GnxecozDKk
Sutopo Purwo Nugroho (@Sutopo_PN) 28. September 2018
“The waves come up with seven meters per second. Who wants to run away from it, must have been hot, Usain Bolt,” says Hermann Fritz from the Georgia Institute of Technology in Atlanta – seven meters per second, the equivalent of more than 25 km/h. Fritz shows the mobile phone film from Palu at the annual meeting of the American Geophysical Union (AGU) in Washington. Together with colleagues, he reported the Attempt to understand the devastating tidal wave better, the on 28. September has devastated the capital of the Indonesian province of Central sulavesi. There had been an earthquake.
“Due to the seismic survey could not accept that there is such a high Tsunami,” explains Fritz the puzzle. That is to say: Actually, the tremors were not supposed to produce really a powerful tidal wave. The quake had a Magnitude of 7.5, the center was located only ten kilometers depth. However, it was a so-called sheet shift within a single continental plate, the Molukkensee-micro-plate.
a Devastating tsunami – like the one in Indonesia in 2004, or in Japan, seven years later – often in a specific geological situation In the area of a so-called subduction zone, a continental plate is pushed under the other and melted. The resulting voltage discharges on a regular basis in the Form of earthquakes, in which large areas on the sea floor moved vertically.
That devastating waves to occur, you can imagine just. Think of a glass of water placed on a table before you with great force to the bottom of the table.
In Palu was the mechanism, but in a different way. Here there was the so-called Palu-Koro fault almost only horizontal displacements of the soil. The table with the glass of water on it, to stay in the picture, was initiated only from the side. Not a classic Tsunami mechanism. Wherein, it has been in Haiti in the year 2010 in such an environment, however, a tidal wave.
at the Time, undersea slip were to blame. And perhaps this is what happened in Palu. Clearly this is not so far.
At the AGU-Meeting of the Indonesian researchers Udrekh Al Hanif of surveys of the seabed have been reported. The Bay of Palu is about as big as the Bodensee, but up to 700 meters deep. Under it is the fault of the two clods constraints in the underground pass each other. The comparison of measurements from the time before the earthquake show large differences to those of then, says Al-Hanif. The meter was moved to the floor. But exact details are not be difficult, because the current measurement data, the old were good, however.
What the researchers say, but A single large event such as a landslide under water, it was not, which led to the flood wave. The underwater data is no evidence. “It must have been a concatenation of numerous circumstances acted,” concludes Hermann Fritz. For this, also speak, says the Geoforscher that the shaft in eye-witness reports from many Parts of the Bay as the same has been described. There is only a single trigger, that would be different.
A large number of smaller landslides under water could have played a role. Soil liquefaction due to the earthquake, which may also have been under the water took place. In addition, the waves are likely to have in the Interior of the Bay, reinforcing each other. Nevertheless, Geoforscher probably still in years of the enigmatic Tsunami, will have to do from Palu.
as good as no time for warnings
One has shown the quake, but A Tsunami warning system is the people in the Region in front of such a flood. “The waves came three minutes after the earthquake,” describes Fritz and displays the document video from surveillance cameras from Palu.
In Japan, one could hope for in a tsunami in the Pacific on 30 minutes ‘ warning time before a Tsunami, also in other Parts of Indonesia to almost as much – and on Chile’s coast, at least 10. The “Golden minutes”, because during this time people could bring. In the case of Palu, it will not have given this period: “The event was unfortunate for the warning centers, because it has shown that you have to be in focus, despite all the progress made on Surprises.”
could you Tsunamis also credits interest to the Swiss large-scale project: How big is the danger of the Alpine lake?
Immediately after the earthquake and tsunami, there had been a discussion about whether the German support installed Indonesian early warning system had failed in the case of Palu. The German research centre for Geosciences in Potsdam, Germany had declared the System to have spent five minutes after the earthquake a warning of a Tsunami with heights of between 0.5 and 3 meters.
Regardless of whether or not this warning poles that result from loss of sirens and Phone someone reached, were as the waves of a long time in the country.
in Total, more than died of 2200 people in the Wake of the earthquake and Tsunami.
In the future, the people of Palu is an important Council, says researcher Fritz: as soon As you felt a long tremor, you would have to run inland. A few hundred meters would be completely rich. Far the waves would not.
However, this few hundred meters of the race, as they still had time – a lot of people in Palu is not done. In the past century, there have been several flood waves in the city, says researcher Fritz. Because no one have thought of in everyday life but apparently. “The historical records were probably not so present.”
Summarized: To date, researchers have difficulties, the backgrounds of the deadly Tsunamis in Indonesia, on 28. To explain September. He had been devastated by a severe earthquake, the area around the city of Palu. But actually, the quake should not have been, because of the geological conditions in the area, even so a strong shaft. Perhaps, among other things, a number of smaller submarine landslides have triggered the deadly waves.