Originally posted by BO XIAN
reply to post by TrueAmerican
I don't recall . . . is the plate Tokyo is on subducting under the plates South and East of it?
Or vice versa?
And what is the rate of subduction?
30+ million people is a lot of looming suffering.
Underscoring the risks facing Japan, a new research institute investigation has determined there is a 70% chance of a magnitude-7 earthquake striking the Tokyo metropolitan area within the next four years, and 98% over 30 years. The March 2011 earthquake was a magnitude-9.
The latest prediction surprised residents, and grabbed headlines in the local media. The government's forecast, using a different methodology, has been that there is a 70% chance of a magnitude-7 quake hitting Tokyo over the next 30 years.
The term "within four years" began trending on Twitter early in the day, with users saying that while the threat of the big one hovered in the back of their minds, the new calculation has made them more aware of the need to make emergency preparations
Originally posted by Human0815
since a few days our media is freaking out
and it seams like the big one is coming soon,
before the preparations are finished
and before Fukushima is cleaned of the sfp!
They expect the epicenter in the north of kantoplain!
Hmmm, not good at all, may the Gods have mercy!
If the fault on the Nankai Trough moves, it could trigger a magnitude 8.0 earthquake, the researchers said, adding they have found a seabed cliff several hundred meters high that was created by the fault's past movements. "There is a high probability that fault shifts have caused great tsunami," said Park Jin Oh, associate professor of marine geology.
"We need to reformulate disaster countermeasures by taking into account an active fault on the seabed 200 km or longer." Park analyzed sonar data on the seabed collected by the Japan Agency for Marine-Earth Science and Technology and found a fault branching off from a boundary between two tectonic plates in an area west of the southern tip of the Kii Peninsula in Wakayama Prefecture.
Originally posted by Human0815
... they have found a seabed cliff several hundred meters high that was created by the fault's past movements. "There is a high probability that fault shifts have caused great tsunami," said Park Jin Oh, associate professor of marine geology.
But it is generally accepted that the Pacific Plate is subducting under the "finger slice" part of the North American Plate that Tokyo is on. And this is what makes it so dangerous, as Tokyo sits on the upper lip of that subduction. In northern Japan near the Kurils, the rate is near 7 to 8 METERS per year. The rate is considerably less in the southern part of Japan, but still high. This makes northern Japan the most active seismic area, and at the most risk, of any other place on the planet.
Originally posted by BO XIAN
There looks to be a kind of angular part of a plate pointing West just South of Tokyo . . . is that point going over or under the plate it's pointing at?
Originally posted by TrueAmerican
Way down the road in the future, that plate may react to the 9.1 too. The Koreas, for example, could potentially get a triggered quake form this activity in Japan.
The 340-kilometer Sagami Trough, also known as Sagami Trench or Sagami Megathrust, originates in the Japan Trench, which runs north to south about 200 kilometers off the coast of eastern Japan. Four or more tectonic plates are presumed to meet at the Sagami Trough and to have triggered massive earthquakes, including the 1923 Great Kanto Earthquake.
Stretching to Sagami Bay, Kanagawa Prefecture, by way of waters between the Izu Islands chain, Tokyo, and the Boso Peninsula, Chiba Prefecture, the Sagami Trough is believed to have caused magnitude-8-class earthquakes every 200 to 400 years.
A Sagami Trough-generated earthquake is expected to be markedly stronger than an earthquake focused just below the metropolitan area, which is expected to be no stronger than magnitude 7.
By many measures, the magnitude 9.0 earthquake that shook Japan a year ago was a record-breaker. It was the largest quake in the country’s written history, the trigger for the worst nuclear accident in 25 years and the costliest natural disaster ever.
Amid such superlatives, it’s easy to forget one more: During the Tohoku-oki quake, the seafloor off Japan’s coast wrenched itself farther apart than scientists had ever measured along any seafloor. In places, chunks of ground slipped horizontally past their neighbors by more than 50 meters and vertically by 10 meters. “The earthquake was a scofflaw,” says Emile Okal, a geophysicist at Northwestern University in Evanston, Ill. “It violated the scaling laws we’re used to.”
That deviant behavior is what made the quake so deadly, by producing a monster tsunami.
When the seafloor moves by half the length of a football field, it displaces an awful lot of water. Of the approximately 20,000 people who died on March 11, 2011, more than 90 percent drowned, were washed away or were otherwise killed by water.
So researchers have been studying what happened off Japan’s coast, seeking ways to better detect a lawless quake, track the resulting tsunami and ultimately save lives. Some of the work, based on survivor videos, reveals how quickly the deadly water surged into and then drained from coastal villages. Other research, looking at ancient sand deposits and boulders tossed like pebbles, suggests that Pacific-wide tsunamis like Tohoku-oki may be more common than once thought.
There’s some good news among the bad. The Japan tsunami was the earliest and best-detected monster wave ever, thanks to warning buoys set up globally after the 2004 Indian Ocean tsunami killed a quarter of a million people. With new findings from the Japan disaster and data from the global buoys, scientists in the United States are working to develop a forecast system that will in principle give people a better warning by predicting areas most likely to flood rather than the heights of incoming waves.
Date-Time Friday, February 24, 2012 at 04:10:35 UTC Friday, February24,2012at 01:10:35PM at epicenter Time of Earthquakein otherTimeZones
Location 35.870°N, 139.874°E
Depth 75.8 km (47.1 miles)
Region NEAR THE SOUTHCOAST OF HONSHU,JAPAN
Distances 23 km (14 miles) NNE of TOKYO, Japan 51 km (31 miles) NNE of Yokohama, Honshu, Japan 76 km (47 miles) S of Utsunomiya, Honshu, Japan 78 km (48 miles) SW of Mito, Honshu, Japan
Location Uncertainty horizontal+/- 17km (10.6 miles);depth +/- 7.1km (4.4miles)
Parameters NST= 43, Nph= 45, Dmin=168.1 km, Rmss=0.93 sec, Gp=115°, M-type=body wave magnitude (Mb), Version=4
Source Magnitude: USGSNEIC (WDCS-D) Location: USGSNEIC (WDCS-D)
Event ID usb000857r