Tsunami expected over 20 meters over a wide area in Hokkaido Kuril-Nippon Trench Earthquake April 21 12:34
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What kind of tsunami will come when a huge earthquake occurs in the "Kishima Trench" and "Japan Trench" off Hokkaido to off Iwate Prefecture? The National Review Board has compiled new assumptions. The height of the tsunami exceeds 20 meters in a wide area of Hokkaido, and it is assumed that there are areas in Tohoku that exceed the Great East Japan Earthquake in Aomori and Iwate prefectures.
In response to the Great East Japan Earthquake that occurred nine years ago, the national study group was in the area from the Kurile Islands to the offshore of Hokkaido along the Kurile Trench, and from the Japan Trench to the south of Hokkaido to the offshore of Iwate Prefecture. Regarding the earthquake that will occur in Japan, we have been considering the assumption of the largest earthquake and the largest tsunami.
Along the Kuril Trench
According to the published assumption, the magnitude of the giant earthquake along the Kuril Trench is magnitude 9.3,
with a seismic intensity of 7 at ▽ Akkeshi and Hamanaka in Hokkaido, and
a severe tremor with a seismic intensity of 6 at the eastern coast of Erimo. I'm supposed to be attacked.
The height of the tsunami exceeded 20 meters in a wide range from Nemuro City to the vicinity of
Erimo Town, and was said to be up to 27.9 meters in Erimo Town and
up to 20.7 meters in Kushiro City.
Along the Japan Trench
On the other hand, a huge earthquake that occurs in the region from the south of Hokkaido to the offshore of Iwate prefecture in the "Japan Trench" has a magnitude of 9.1, and a part of Aomori prefecture and the southern part of Iwate prefecture will be hit by a violent shaking with a seismic intensity of 6+ It has been.
The height of the tsunami exceeds 10 meters in each region of Tohoku
▽ Hachinohe City, Aomori Prefecture, up to 26.1 meters,
▽ Miyako City, Iwate Prefecture, up to 29.7 meters,
some areas even surpass the Great East Japan Earthquake.
Huge earthquake and tsunami "imminent"
It is said that large earthquakes have repeatedly occurred in the past in the area where the new assumptions have been summarized, and the study group states that the "largest class tsunami is" imminent ". The Cabinet Office, is this a result of the original to consider the specific damage estimation and disaster prevention measures, and summarize policy in prospect in the current fiscal year.
Significance and history of new assumptions
The new assumptions are based on the lessons learned from the Great East Japan Earthquake that occurred 9 years ago.
Since the huge earthquake that caused the earthquake was much larger than the conventional assumption, the country needs to consider the largest scientifically considered earthquake and tsunami. We have reviewed the assumptions of the "Tokyo Metropolitan Earthquake".
The assumptions that followed this time were the following:
▽ The area of "Kishima Trench" from off Tokachi to Nemuro of Hokkaido, and
▽ Of the "Japan Trench", from off Hidaka of Hokkaido to Sanriku of Iwate Prefecture. The offshore area.
The largest tsunami was assumed based on a survey of tsunami deposits over the past 6000 years found in the coastal areas of Hokkaido to Iwate Prefecture.
According to the study group, it seems that huge tsunamis occurred in every region with a period of about 300 to 400 years, causing a large tsunami.
The last major tsunami in any area seems to have occurred around the 17th century, and it has already been about 400 years. For this reason, the study group of the country says that “the occurrence of the largest tsunami is imminent” in two areas, and “it is necessary to immediately implement disaster prevention measures”.
Tsunami height and depth of inundation
Details of the height of the tsunami and the depth of inundation expected from the giant earthquake off the coast of Hidaka in Hokkaido to off the coast of Sanriku in Iwate Prefecture, out of the Kuril Trench and the Japan Trench.
Kuril Trench / Hokkaido
In the event of a huge earthquake of the largest class along the Kuril Trench, a tsunami of more than 20 meters is expected over a wide area in Hokkaido, centering on the eastern coast of Erimo.
▽ Erimo was the highest with a maximum of 27.9 meters,
▽ Kushiro was a maximum of 27.3 meters,
▽ Hiroo was a maximum of 26.1 meters, and
▽ Nemuro was a maximum of 22 meters.
The depth of the inundation
was 8.4 meters after the earthquake at Akkeshi Town Hall, 8.1 meters after the earthquake, 6.7 meters at
Shiranuka Town Hall after 6.3
minutes, and 5.9 meters after Kushiro City Hall after 34 minutes.
Japan Trench / Hokkaido
This is the height of the tsunami and the depth of inundation in each area when a huge earthquake occurs in the region from Hidaka off Hokkaido to Sanriku off Iwate Prefecture in the "Japan Trench."
In Hokkaido, a tsunami of about 10 meters was hit in the west of Erimo town
▽ Kawamachi was up to 14.5 meters,
▽ Tomakomai city was up to 9.9 meters,
▽ Hakodate city was up to 9.5 meters.
The depth of inundation
was 10.6 meters after 1 hour and 10 minutes from the earthquake at Samani Town Hall,
6.8 meters after 1 hour 19 minutes at Hidaka Town Hall,
and 4.5 meters after 2 hours and 12 minutes at Muroran City Hall. It was
Japan Trench / Aomori Prefecture
The height of the tsunami on the Pacific coast of Aomori Prefecture is expected to be 10 to 20 meters, which exceeds the Great East Japan Earthquake.
▽ Hachinohe City is the highest with a maximum of 26.1 meters,
▽ Misawa City is a maximum of 15.9 meters,
▽ Rokkasho Village is a maximum of 10.7 meters.
The depth of inundation was
▽ at Kazamaura Village
Office , 6.2 meters 34 minutes after the earthquake, and ▽ Aomori Prefectural Office was 1.7 meters 1 hour and 41 minutes later.
Japan Trench / Miyagi prefecture, Fukushima prefecture
The tsunami hits a wide area in Miyagi and Fukushima prefectures, and depending on the location, a tsunami that exceeds 10 meters is expected.
In Miyagi Prefecture,
Kesennuma City was the highest with a maximum of 15.3 meters,
▽ Minamisanriku Town with a maximum of 12.6 meters, and
▽ Miyagino Ward in Sendai City with a maximum of 8.5 meters.
The depth of inundation was
▽ Ishimaki City Hall 2.1 meters 4 hours and 12 minutes after the earthquake.
In Fukushima Prefecture, ▽ Minamisoma City was the highest with a maximum of 19 meters,
▽ Namie Town with a maximum of 18.9 meters,
▽ Soma City with a maximum of 16.1 meters,
▽ Okuma Town with a maximum of 14.1 meters.
Japan Trench / Ibaraki prefecture, Chiba prefecture
The tsunami reached the Kanto coast, and in
Ibaraki prefecture,
▽ Kitaibaraki city had the highest 6.5 meters,
▽ Hitachi city had 4.9 meters,
▽ Tokai village had 5 meters, and
▽ Kamisu city had 5.7 meters.
In Chiba prefecture,
▽ Asahi was the highest with a maximum of 6.6 meters,
▽ Choshi was a maximum of 5.4 meters,
▽ Kujuri was a maximum of 3.5 meters, and
▽ Tateyama was a maximum of 2.8 meters.
The Japan Trench and Iwate will be announced in the future
On the other hand, in Iwate prefecture, it is expected that a tsunami of 10 to 20 meters will hit each area and reach 29.7 meters in the high areas of Miyako City. Is not published.
The Iwate Prefecture has yet to make adjustments with the locals, so the study group wants to announce it as soon as the adjustments are complete.
Expert “The measures so far are effective”
Hiroaki Takahashi, a professor at the Graduate School of Hokkaido University who is familiar with disaster prevention of tsunami, said about the new assumptions announced this time, "The contents are almost the same as the one originally announced by Michi in 2012, in a sense, it has a national approval. I think we have come up with a new assumption. ”He acknowledged that the measures that have been implemented so far are effective.
On that basis, “Based on this flood inundation, the country will begin to consider damage estimation and disaster prevention measures in the future, but we do not know when the tsunami will occur. Instead of waiting for the country's measures to proceed, I would like you to think about what kind of measures you need to take in your area. "It is important for each local government and residents to further strengthen the measures.
Also, this time, the country's study group said that "the largest class tsunami is imminent", saying "Because the country demands a fairly strong response based on the evidence of scientific data, , "I want you to think that it's not strange when a tsunami will occur."