Why earthquake in japan

A false alarm could occur, for example, if waves from a different earthquake bounced off Earth's internal structures and then were picked up by the seismic array, the team notes in the study. But John Vidale , a seismologist at the University of Southern California, says that the seismic signals appear to come from a true quake at least as deep as the study authors suggest.

Additional confirmation of the event could come from searching for another type of earthquake wave , known as a shear or S-wave. The new study identifies the quakes using pressure waves, or P-waves, which rapidly travel through the ground like a slinky pulled forward and back. S-waves travel slower and rock the ground side to side or up and down.

If the S and P waves arrive at the expected time based on the position where the team believes this ultradeep quake occurred, Vidale says, "that kind of nails it. However, Vidale points out that even if the depth can be confirmed, the boundary of the lower mantle at this location is still an open question.

Seismic imaging hints that as the slab sinks into the dense rocks of the lower mantle, it starts folding back and forth "like a wet noodle," Houston says.

The accumulation of cold seafloor rocks could cool the surrounding rocks, pushing the lower mantle boundary to greater depths, and making the system much more complex to interpret, she says.

Studying the Earth's interior is never easy. Editor's note: T he scientific journal where the new study was published has been corrected to Geophysical Research Letters. All rights reserved. Share Tweet Email. Read This Next Wild parakeets have taken a liking to London. Animals Wild Cities Wild parakeets have taken a liking to London Love them or hate them, there's no denying their growing numbers have added an explosion of color to the city's streets. India bets its energy future on solar—in ways both small and big.

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Animals Wild Cities Wild parakeets have taken a liking to London. Animals Wild Cities Morocco has 3 million stray dogs. Here, the plates slide over liquid rock and cause tension, which is eventually released and expressed as earthquakes. The Japan Trench is an meter-long deep oceanic trench in the northwestern part of the Pacific, with a depth of 8, meters. In , seismically active volcanoes with a height of 50 meters were discovered 5, meters within the trench and believed to be responsible for the Tohoku Earthquake in March If you are indoors , seek shelter under a stable table or door frame and stay away from anything that could fall on you.

If you are outside , find an open area away from trees, machines, buildings. For specific details on where to get information in English, find help, and what to do during an emergency, see our guide to getting help in Japan during disasters, medical problems, or crimes. Also, pay attention to announcements or warnings made from loudspeakers in most cities and towns in Japan.

If you have a phone with a Japanese phone number, you will receive a notification to your smartphone. This extends to users with data-only sim cards as well. For more information about apps or websites with English disaster information, please check our guide to getting help in Japan.

Some of the most destructive earthquakes occurred almost a century ago, while others happened in the recent past. On September 1st, , an earthquake with a magnitude of 7. The aftermath also triggered a massive city fire, and casualties rose to over , The earthquake not only led to major fires in the metropolitan region but also resulted in a meter-high tsunami wave that hit Sagami Bay. The bay, located in the south of Kanagawa Prefecture, was also the hypocenter of the earthquake, and the landmasses of the bay shifted two meters upwards during the quake.

On January 17th, , an earthquake with a magnitude of 7. On March 11, , the strongest ever recorded earthquake in Japan triggered a massive tsunami along the Pacific Coast of northeastern Japan.

Known as the Great East Japan Earthquake , the earthquake and particularly the ensuing tsunami killed nearly 20, people and caused a nuclear accident at a power plant in Fukushima Prefecture. The Japanese shindo scale is most commonly used in Japan to describe earthquakes. Shindo refers to the intensity of an earthquake at a given location, i. The shindo scale ranges from shindo one, a slight earthquake felt only by people who are not moving, to shindo seven, a severe earthquake. Shindo two to four are still minor earthquakes that do not cause damage, while objects start to fall at shindo five, and heavier damage occurs at shindo six and seven.

Every household should keep a survival kit with a flashlight, a radio, a first aid kit and enough food and water to last for a few days. Avoid placing heavy objects in places where they could easily fall during an earthquake and cause injury or block exits. Have a fire extinguisher. Familiarize yourself with the designated evacuation area in your neighborhood. Falling objects, toppling furniture and panic present the greatest dangers during an earthquake.

The Pacific plate reportedly tends to transmit seismic waves without weakening them. Although jolts spread right above the epicenter for regular earthquakes, no noticeable quakes were recorded in the recent one along the Sea of Japan. Furumura said, "The recent earthquake's size and seismic intensity are not especially noteworthy.

But in zones with anomalous seismic intensity, the relationship between the epicenter and areas with great jolts differs from regular cases, so it's necessary to take heed of this.