Tsunami of April 7, 2011

West Coast/Alaska Tsunami Warning Center, NOAA/NWS

TSUNAMI of 7 April 2011 (Near East Coast of Honshu, Japan)

A major earthquake with a moment magnitude of 7.1 (USGS magnitude) occurred at 14:32:41 UTC 7 April 2011 (day 097) and was located 41 miles/66 km E of Sendai, Honshu, Japan (38.253N, 141.64E, 30.4 mi/49 km depth--USGS location).

This earthquake produced a small tsunami that was recorded at the Ofunato, Japan tide gage operated by the Japanese Meteorological Agency which is monitored at the Tsunami Warning Centers. Many observatories provide data to the centers; such as the NOAA National Ocean Service, the University of Hawaii Sea Level Center, the Chilean Navy, and the National Tidal Facility in Australia among others. Click on the site name to see a graph of the tsunami, when available. Listed wave heights are maximum amplitude in cm (above sea level). Observed Arrival time is the actual tsunami arrival time in UTC on gages where it could be determined. The Computed Arrival time is the estimated time of arrival computed at the National Tsunami Warning Center (NTWC) based on the origin time and location. The Sample Interval column shows the time between samples.

For additional information about this tsunami event see the Pacific Tsunami Warning Center's homepage.

Tide gage/
Measurement Location

Estimated Arrival Time
[UTC (J.Day)]

Observed Arrival time
[UTC (J.Day)]

Peak amplitude
(above sea level in cm)

Time of Peak Amplitude Measurement
[UTC (J.Day)]

Initial motion

Sample Interval

Data File

Data File

Graphic of
Filtered data


1505 (097)

1453 (097)


1457 (097)