National Tsunami Warning Center, NOAA/NWS

Tsunami of 1 May, 2017 (Elfin Cove, Alaska)

A strong earthquake with a moment magnitude of 6.2 (USGS magnitude) occurred at 12:31:55 UTC 1 May, 2017 (day 121) and was located 34 m/55 km NNW of Mosquito Lake, Alaska (59.844N, 136.695W, 2.0 km/ 1.3 mi depth -- USGS location).

This earthquake produced a tsunami that was recorded at a single tide gage monitored by the National Tsunami Warning Center (NTWC). Many observatories provide data to the centers; such as the NOAA National Ocean Service, the U. of Hawaii Sea Level Center, the Chilean Navy, the Japan Meteorological Agency 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 wave arrival computed at the NTWC based on the earthquake origin time and location. The Sample Interval column shows the time between data samples.


Location of Earthquake
(Click to enlarge)

Distance to recording gauge
(Click to enlarge)


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)]

Model Forecast Amplitude
(above sea level in cm)

Initial motion

Sample Interval

Data File
(Julian Day Starts
at 0000 UTC)

Elfin Cove, Ak

Enlarged view

1730 (125)

1237 (121)


1315 (121)




121, 122

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