2007 Chūetsu offshore earthquake

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Landslide in Omigawa

The Niigata - Chuetsu - coast earthquake 2007 (Japanese新泻 県 中 越 冲 地震, Niigata-ken Chuetsu oki jishin; literally " prefecture Niigata - Chuetsu - coast earthquake ", English " Niigata - Chuetsu Oki Earthquake " ) was a strong earthquake with the moments magnitude Mw = 6.6 and occurred on 16 July 2007 at 10:13 local time clock in the northwest of Niigata Prefecture, off the west coast of Japan. The quake shook Niigata and neighboring prefectures. Kashiwazaki, Iizuna and Kariwa registered the highest seismic intensity on the Japanese Shindo scale, but the quake was also felt in Tokyo. Eleven people were killed and nearly two thousand injured.

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Through the quake were mostly existing buildings destroyed wooden structures. Tore up roads and landslides made ​​some roads and railways impassable. These landslides were mainly concentrated on the area about 10 km northeast of Kashiwazaki and about 7 km east of the nuclear power plant. The slide around geratenen strata were powerful in general between half a meter and five meters. Among the most important infrastructure elements that were affected include the coastal road north of the Kashiwazaki - Kariwa nuclear power plant, the railroad south of Kashiwazaki and the Omigawa station on the Shin'etsu line. The National Highway 8 was destroyed north of the intersection with the national road 252, at a location which is about 10 km from the coastline. In this landslide in about 150,000 cubic meters of material were moved, the earth masses were slipping down to a depth of between six and eleven meters. Roads were displaced by the quake between ten centimeters and one meter in height and thereby partially impassable. The tremor eleven people were killed and 1957 injured. 1096 buildings collapsed completely in 2679 and a partial, more 27 807 buildings were damaged. Chance came damage to port facilities and buildings on coastal protection.

Reactions and Help

Japanese Prime Minister Shinzo Abe interrupted a campaign trip in southern Japan to visit Kashiwazaki and promised " to make every effort in the rescue and restore the gas and electricity supply ."

The earthquake occurred at a Japanese holiday. The earthquake was quickly declared a " major disaster ", whereby 80 % of the cost of rescue and restoration of the infrastructure of the affected regional government will be replaced by the nationwide state budget by the Prime Minister. Since this disaster occurred just two weeks before the 2007 election Sangiin, the Cabinet showed a lively presence on the ground. Immediately after the quake, middle schools had been provided to 11,000 evacuees shelter in ground and the power supply was largely restored within three days, so many evacuees could return to their undamaged homes. They were, however, rely on the guarantee of food and drinking water, as the supply network for water and gas in many places was out of service. Until 30 July 2007, the water supply for 95 % of households could be put back into operation in Kashiwazaki and the surrounding area, but only for 15% of households could up to this point, the gas supply will be restored.

By experts, the houses were in the first week after the earthquake in the affected area examined to see whether their statics residents allowed a safe return. With this review, an assessment of the damage caused by the earthquake was connected. On July 23, the Prefect of Niigata states that the total damage of the earthquake amounts to around 3 trillion yen, with about 880 billion yen accounting for indirect costs associated with production losses in nuclear power plant Kashiwazaki, the decline in tourism and other economic consequences related.

Tectonic review

The earthquake with a magnitude of 6.6 had its epicenter west of the coast of Honshu, Japan, in a compression zone, which is located in the border area of ​​Amurplatte and the Okhotsk plate. ( It is debatable whether these two microplates are independent or part of the Eurasian plate or the Pacific. ) In this area, the Okhotsk plate moves at a speed of nine millimeters annually in west-north- westerly direction towards the Amur plate. The two plates have relatively small-scale expansions and lie between the Eurasian plate and the Pacific plate. The Pacific plate pushes with more than 90 mm annually against the Eurasian plate. This relative movement takes place mainly about 400km east-southeast of the epicenter of the earthquake on where the Pacific plate dives under the Okhotsk plate ( subduction ).

The flat Erdkrustenbeben followed 13 hours later in depth located quake. This earthquake with a moment magnitude of MW = 6.8 to 330 km further west occurred, in 350 km depth beneath the Sea of ​​Japan. The two earthquakes were triggered by two different mechanisms. The first earthquake was caused by a deformation of the earth's crust in the area of the Okhotsk plate, while the second was probably caused by kinking of the subducting Pacific plate. Due to the different mechanisms and the spatial distance, it can be assumed that this is not an aftershock.

Shallow earthquakes often cause more damage than those that occur at great depths, because the energy of the shallow earthquakes occur at a shorter distance to the surface. This stronger surface waves are excited, which are ultimately responsible for the damage of earthquakes.

Two days after the initial earthquake stronger aftershock was registered, which reached a value of 4 on the Shindo scale in Izumozaki, Niigata Prefecture

Impact on the production of motor vehicles

Toyota had to stop production at all of its factories to stop because a work for items in Kashiwazaki of the earthquake had been damaged. Also, Nissan has had to shut down two factories.

Production started in the works of Toyota, Mazda and Honda on July 25, again after damaged facilities, as well as the water and gas supply had been repaired in the region. It is estimated that the loss of production at Toyota amounted to 46000-55000 vehicles at Nissan it was 12,000 cars. Extra shifts were planned to compensate for the loss.

Incidents in the Kashiwazaki - Kariwa nuclear power plant

In a transformer station of the Kashiwazaki - Kariwa nuclear power plant broke through in the quake from a fire that was deleted after two hours. The quake also caused a leak in a water cycle and therefore joined a small amount of radioactive material into the sea, but according to the authorities thus there was no danger to the environment. The power plant, one of the most powerful in the world, was still off on the instructions of the Japanese government until the safety studies have been completed. The International Atomic Energy Agency ( IAEA) experts offered, which was first described by the Japanese government as required. Later, however, the government agreed to the request of the Niigata Prefecture, as this will clear up doubts in the public about the safety of the nuclear reactor thereby.

The acceleration during the quake on the foundations of the seven reactors that are spread over a distance of 1,700 meters, amounted to 0.69 g were acceleration values ​​388-867 cm / s ² measured. The foundations of the reactors range from 45 to 26 meters below the ground surface.