Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Fukushima at increased earthquake risk

14.02.2012
Seismic risk at the Fukushima nuclear plant increased after the magnitude 9 earthquake that hit Japan last March, scientists report.
The new study, which uses data from over 6,000 earthquakes, shows the 11 March tremor caused a seismic fault close to the nuclear plant to reactivate. The results are now published in Solid Earth, an open-access journal of the European Geosciences Union (EGU).

The research suggests authorities should strengthen the security of the Fukushima Daiichi nuclear power plant to withstand large earthquakes that are likely to directly disturb the region. The power plant witnessed one of the worst nuclear disasters in history after it was damaged by the 11 March 2011 magnitude 9 earthquake and tsunami. But this tremor occurred about 160 km from the site, and a much closer one could occur in the future at Fukushima.

(From the paper.) Map of Japan’s islands indicating the area of study (black box). The purple star marks the epicentre of the 11 March earthquake and the red star the Iwaki epicentre. Fukushima Daiichi is highlighted by a red square. Black triangles indicate active volcanoes. Numbers on the side of the image represent latitude and longitude. Credit: Ping Tong, Dapeng Zhao and Dinghui Yang

¡°There are a few active faults in the nuclear power plant area, and our results show the existence of similar structural anomalies under both the Iwaki and the Fukushima Daiichi areas. Given that a large earthquake occurred in Iwaki not long ago, we think it is possible for a similarly strong earthquake to happen in Fukushima,¡± says team-leader Dapeng Zhao, geophysics professor at Japan¡¯s Tohoku University.

The 11 April 2011 magnitude 7 Iwaki earthquake was the strongest aftershock of the 11 March earthquake with an inland epicentre. It occurred 60 km southwest of the Fukushima nuclear power plant, or 200 km from the 11 March epicentre.

The research now published in EGU¡¯s Solid Earth shows that the Iwaki earthquake was triggered by fluids moving upwards from the subducting Pacific plate to the crust. The Pacific plate is moving beneath northeast Japan, which increases the temperature and pressure of the minerals in it. This leads to the removal of water from minerals, generating fluids that are less dense than the surrounding rock. These fluids move up to the upper crust and may alter seismic faults.

¡°Ascending fluids can reduce the friction of part of an active fault and so trigger it to cause a large earthquake. This, together with the stress variations caused by the 11 March event, is what set off the Iwaki tremor,¡± says Ping Tong, lead author of the paper.

The number of earthquakes in Iwaki increased greatly after the March earthquake. The movements in the Earth¡¯s crust induced by the event caused variations in the seismic pressure or stress of nearby faults. Around Iwaki, Japan¡¯s seismic network recorded over 24,000 tremors from 11 March 2011 to 27 October 2011, up from under 1,300 detected quakes in the nine years before, the scientists report.

The 6,000 of these earthquakes selected for the study were recorded by 132 seismographic stations in Japan from June 2002 to October 2011. The researchers analysed these data to take pictures of the Earth¡¯s interior, using a technique called seismic tomography.

¡°The method is a powerful tool to map out structural anomalies, such as ascending fluids, in the Earth¡¯s crust and upper mantle using seismic waves. It can be compared to a CT or CAT scan, which relies on X-rays to detect tumours or fractures inside the human body,¡± explains Zhao.

While the scientists can¡¯t predict when an earthquake in Fukushima Daiichi will occur, they state that the ascending fluids observed in the area indicate that such an event is likely to occur in the near future. They warn that more attention should be paid to the site¡¯s ability to withstand strong earthquakes, and reduce the risk of another nuclear disaster.

The scientists also note that the results may be useful for reviewing seismic safety in other nuclear facilities in Japan, such as nearby Fukushima Daini, Onagawa to the north of Fukushima, and T¨­kai to the south.

Information for editors
This research is presented in the paper ¡®Tomography of the 2011 Iwaki earthquake (M 7.0) and Fukushima nuclear power plant area¡¯ to appear in the EGU open-access journal Solid Earth on 14 February 2012.

The scientific article is available online, from the publication date onwards, at http://www.solid-earth.net/recent_papers.html.

The discussion paper (not peer-reviewed) and reviewers comments is available at http://www.solid-earth-discuss.net/3/1021/2011/sed-3-1021-2011.html.

The team is composed of Ping Tong (Tohoku University, Sendai, Japan [Tohoku] and Tsinghua University, Beijing, China [Tsinghua]), Dapeng Zhao (Tohoku), Dinghui Yang (Tsinghua).

The European Geosciences Union (EGU, www.egu.eu) is Europe¡¯s premier geosciences union, dedicated to the pursuit of excellence in the Earth, planetary, and space sciences for the benefit of humanity, worldwide. It is a non-profit interdisciplinary learned association of scientists founded in 2002. The EGU has a current portfolio of 14 diverse scientific journals, which use an innovative open-access format, and organises a number of topical meetings, and education and outreach activities. Its annual General Assembly is the largest and most prominent European geosciences event, attracting over 10,000 scientists from all over the world. The meeting¡¯s sessions cover a wide range of topics, including volcanology, planetary exploration, the Earth¡¯s internal structure and atmosphere, climate change, and renewable energies.

The 2012 EGU General Assembly is taking place is Vienna, Austria from 22-27 April. For information regarding the press centre at the meeting and media registration, please check http://media.egu2012.eu/.

Contacts
Prof Dapeng Zhao
Department of Geophysics, Tohoku University
Sendai, Japan
Tel: +81-22-225-1950 or +81-22-795-6780
Email: zhao@aob.gp.tohoku.ac.jp
B¨¢rbara T. Ferreira
EGU Media and Communications Officer
Munich, Germany
Tel: +49-89-2180-6703
Email: media@egu.eu

Dr. B¡§¢rbara T. Ferreira | idw
Further information:
http://media.egu2012.eu
http://www.egu.eu/

More articles from Earth Sciences:

nachricht Water - as the underlying driver of the Earth’s carbon cycle
17.01.2017 | Max-Planck-Institut für Biogeochemie

nachricht Modeling magma to find copper
13.01.2017 | Université de Genève

All articles from Earth Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: How gut bacteria can make us ill

HZI researchers decipher infection mechanisms of Yersinia and immune responses of the host

Yersiniae cause severe intestinal infections. Studies using Yersinia pseudotuberculosis as a model organism aim to elucidate the infection mechanisms of these...

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.

As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).

Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

127 at one blow...

18.01.2017 | Life Sciences

Brain-Computer Interface: What if computers could intuitively understand us

18.01.2017 | Information Technology

How gut bacteria can make us ill

18.01.2017 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>