04:14 GMT +323 October 2018
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    Tidal wave may hit Russia's Far East

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    MOSCOW. (RIA Novosti commentator Tatyana Sinitsyna) - On December 26, 2004, an undersea earthquake with an epicenter off the west coast of Sumatra, Indonesia, triggered a series of tidal waves in the Indian Ocean.

    With a power of 100 Hiroshima bombs, it killed more than 225,000 people in 11 countries, including Indonesia, India, Sri Lanka and Thailand, as well as tourists from the Untied States and Europe, 10 Russians among them.

    Scientists have recently analyzed new earthquake data and warn that the Kuril Islands, Sakhalin and Kamchatka can become new tsunami targets.

    The Sumatran tidal wave rolled around the globe, with quakes registered in the Atlantic and Pacific oceans, and as far away from the epicenter as Obninsk near Moscow, where an earthquake monitoring station is located. Unfortunately, there is no global tsunami warning center, and the victims of the 2004 tidal wave could not be warned.

    There have been 1,050 tidal waves in the recorded history of the world, including 100 described as catastrophic. The 2004 tsunami was one of the three biggest. It was triggered off by an earthquake on the bottom of the Indian Ocean, 10 km (6 miles) under the surface and 42 km (26 miles) north of Simeulue Island.

    Tsunami is the ultimate result of earthquakes, the ocean's response to processes underway in the earth's core, mantle and crust.

    "A tidal wave sets nearly the whole of the ocean in motion, as its average depth is 4 km (2 miles). This is the main feature distinguishing a tidal wave from a storm or cyclone, which affect only the upper layer of the ocean," said Professor Yevgeny Kulikov, head of the tidal waves laboratory at the Oceanology Institute of the Russian Academy of Sciences.

    According to him, the traditional assessment of tsunamis has until recently been based on the statistical analysis of historical and instrumental data of the strongest earthquakes, with a magnitude of 8 and higher, registered every 150-200 years. The tragedy in the Indian Ocean showed that such monitoring is not enough to make statistical conclusions and predict the probability of such disasters. This encouraged scientists to make computer models of physical processes for assessing their danger.

    Ocean plateaus move away from the ridge between them towards nearby continents at a pace of several centimeters a year. Contact with continental plateaus pushes the relatively thin ocean plateaus down into the earth's crust. When enough energy is accumulated, it is released in the form of a major earthquake, pushing one part of the plateau up and the other down. Such sudden shifts on the ocean's bed form tidal waves.

    The Sumatran disaster forced scientists to change their views of the immediate danger of tidal waves. Before that, they used the relevant data for the past 100-150 years to calculate the possible height of the wave. This encouraged them to rank the Indian Ocean, where the tragedy occurred, as a moderate risk zone. But we know now that a lengthy "seismic silence" is suspicious.

    Russia has a suspicious "seismic silence" zone in the middle of the Kuril Islands. It has been very quiet there for more than 100 years, which worries scientists because the Sumatran zone had kept silence for 200 years. During that period, a huge amount of energy accumulated in the earth's crust, which resulted in the devastating earthquake and tidal wave.

    Scientists warn that the consequences of a potentially powerful earthquake in the Kurils could be extremely destructive for the Kurils and also for Kamchatka and Sakhalin.

    There are deep straits near the mid-Kurils through which the energy of a tsunami originating in the Pacific can easily reach into the Sea of Okhotsk and Sakhalin. Computer modeling indicates the potential danger of a tidal wave there. The most important result of the study is the height of the wave on the eastern coast of Sakhalin, where the oil and gas producing infrastructure is located.

    "When project operator Sakhalin Energy launched its oil projects there, scientists had a different attitude to tsunamis," Kulikov said. "We thought that the wave would not rise higher than half a meter on the eastern coast of Sakhalin. But new data shows that if a powerful earthquake happens in the mid-Kurils, the wave would rise to 4-5 meters, and some scientists predict a 10-meter wave."

    Such a wave will destroy the entire oil infrastructure in the zone, including drilling rigs, pipelines and buildings. Scientists have concluded that oil and gas pipelines run too close to low waterline, barely 100-150 meters, and must be shifted further inland.

    Man cannot defeat a tidal wave, but he can at least find ways to predict them. Satellite monitoring offers the best way to register tsunamis. It can show the wave before it hits and warn the people about the danger. Today it takes several days to process satellite images, and catching a tsunami in mid-path is impossible, because everything happens in a matter of seconds. In other words, we need regular monitoring of the world's oceans.

    This program could be best implemented with the assistance of deepwater tsunami gauges. They can be placed along the entire coastline, protecting Russia from surprise tsunamis near the Kurils and Kamchatka. This is the goal of the federal target program of tsunami warning.

    "We have devised an original technology of early tsunami warning, which offers a new way to register tidal waves at underwater stations," said Professor Mikhail Gokhberg, director for physical fields at the Schmidt Institute of Earth Physics of the Russian Academy of Sciences. "We take electromagnetic measurements from gauges placed on the bottom of the ocean. The underwater electromagnetic station can not only warn about a tsunami, but also show the direction of its movement."

    According to the scientist, the current gauges of underwater pressure are not effective, because a tsunami signal differs radically from the earth's magnetic field signals and magnetic storms. The electromagnetic method allows distinguishing the voice of the tsunami from the interference noise.

    "We have devised an algorithm that uses electromagnetic variations to compile the image of a tsunami in real time," Gokhberg said. "This allows us to register the wave 10 to 15 minutes before it hits the coast. Electromagnetic gauges start registering information when a tidal wave passes overhead, so that the people have 15 minutes to run from it before it hits."

    The opinions expressed in this article are the author's and do not necessarily represent those of RIA Novosti.

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