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Home > Weather and Earthquakes > Tsunami Warnings/Advisories, Tsunami Information

Tsunami Information (Tsunami Observation)

Tsunami Information
This Tsunami Information was issued in the past
Occurred at 14:46 JST 11 Mar 2011
Region name Sanriku Oki
Depth about 10 km
Magnitude 7.9
Initial Tsunami Observation
Click the map to zoom in

Maximum Tsunami Observation

Tsunami Information NUMBER 5
(Tsunami Observations)

Issued at 15:10 JST 11 Mar 2011

Tsunami Observations
As of 15:10 JST
In some coastal regions, it is inferred that tsunamis higher than those recorded at observation sites have arrived.
Tsunamis may be higher than those recorded at observation sites.

HachinoheInitial Tsunami  14:47 JST 11 Mar    (+)    Slight  
Maximum Tsunami  14:49 JST 11 Mar    Slight  
Mutsu-shi SekinehamaInitial Tsunami  14:48 JST 11 Mar    (+)    Slight  
Maximum Tsunami  14:54 JST 11 Mar    Slight  
MiyakoInitial Tsunami  14:48 JST 11 Mar    (+)    0.2 m  
Maximum Tsunami  14:54 JST 11 Mar    0.2 m  
OfunatoInitial Tsunami  14:46 JST 11 Mar    (-)    0.2 m  
Maximum Tsunami  14:54 JST 11 Mar    0.2 m  
KamaishiInitial Tsunami  14:45 JST 11 Mar    (-)    0.1 m  
Maximum Tsunami  14:56 JST 11 Mar    0.2 m  
Iwate Kamaishi-oki*Initial Tsunami  14:50 JST 11 Mar    Unknown
Iwate Miyako-oki*Initial Tsunami  14:50 JST 11 Mar    Unknown
Iwate Kuji-oki*Initial Tsunami  14:56 JST 11 Mar    Unknown
Ishinomaki-shi AyukawaInitial Tsunami  14:46 JST 11 Mar    (+)    0.1 m  
Maximum Tsunami  14:52 JST 11 Mar    0.5 m  
Fukushima Onahama-oki*Initial Tsunami  14:52 JST 11 Mar    Unknown

Tsunami Warnings and/or Advisories are in currently effect for the following coastal regions of Japan:
<Tsunami Warning (Major Tsunami)>
  IWATE PREF.
  MIYAGI PREF.
  FUKUSHIMA PREF.
<Tsunami Warning (Tsunami)>
  CENTRAL PART OF PACIFIC COAST OF HOKKAIDO
  PACIFIC COAST OF AOMORI PREF.
  IBARAKI PREF.
  KUJUKURI AND SOTOBO AREA, CHIBA PREF.
  IZU ISLANDS
<Tsunami Advisory>
  EASTERN PART OF PACIFIC COAST OF HOKKAIDO
  WESTERN PART OF PACIFIC COAST OF HOKKAIDO
  JAPAN SEA COAST OF AOMORI PREF.
  UCHIBO AREA, CHIBA PREF.
  OGASAWARA ISLANDS
  SAGAMI BAY AND MIURA PENINSULA
  SHIZUOKA PREF.
  PACIFIC COAST OF AICHI PREF.
  SOUTHERN PART OF MIE PREF.
  WAKAYAMA PREF.
  TOKUSHIMA PREF.
  KOCHI PREF.
  MIYAZAKI PREF.
  TANEGASHIMA AND YAKUSHIMA AREA
  AMAMI ISLANDS AND TOKARA ISLANDS
Although there may be slight sea-level changes in coastal regions other than the above, no tsunami damage is expected in those coastal regions.

Earthquake Information
 Occurred at 14:46 JST 11 Mar 2011
 Region name SANRIKU OKI
 Latitude38.0N
 Longitude142.9E
 Depth about 10 km
 Magnitude 7.9

*** [Tsunami Observed by offshore GPS buoys(marked with *)] ***

Please note that heights of all tsunamis observed by offshore GPS buoys are described as Unknown in the above text in order to avoid confusion with those observed by tidal stations in coastal areas.
Below are the details of tsunamis observed by offshore GPS buoys.

Iwate Kamaishi-oki*Initial Tsunami  14:50 JST 11 Mar    (-)    0.3 m  
Maximum Tsunami      Arrival of maximum tsunami expected.  
Iwate Miyako-oki*Initial Tsunami  14:50 JST 11 Mar    (-)    0.4 m  
Maximum Tsunami      Arrival of maximum tsunami expected.  
Iwate Kuji-oki*Initial Tsunami  14:56 JST 11 Mar    (-)    0.1 m  
Maximum Tsunami      Arrival of maximum tsunami expected.  
Fukushima Onahama-oki*Initial Tsunami  14:52 JST 11 Mar    (+)    1.0 m  
Maximum Tsunami  15:04 JST 11 Mar    1.0 m  

All tsunamis described here were observed offshore, and are therefore expected to increase in size by the time they reach coastal areas.

** [Estimated tsunami heights and arrivals times at coastal areas near offshore GPS buoys] **
Below are the estimated tsunami heights and arrival times at coastal areas near offshore GPS buoys.

Estimated Tsunami Arrival TimeEstimated Tsunami Height
Iwate Kamaishi  14:55 - 15:10 JST 10 Mar    0.5 m  
Iwate Miyako  14:55 - 15:10 JST 10 Mar    1 m - 2 m  
Iwate Kuji  15:01 - 15:16 JST 11 Mar    0.5 m  
Fukushima Onahama  14:57 - 15:12 JST 10 Mar    1 m - 4 m  

Tsunamis may have already arrived in some areas.