August 5, 1927 Tsunami: Sanriku, Japan
A tsunami caused by a magnitude 6.9 earthquake began at Sanriku, Japan on August 5, 1927 at 21:13:01 UTC. The water rose as high as 0.1 meters. Its effects were recorded at 5 places.
Where the waves reached
The source (white) and every runup with a place, colored by the water height recorded there. A ring is a runup NCEI marks doubtful.
- Under 1 m
- 1 to 3 m
- 3 to 10 m
- 10 to 30 m
- 30 m and more
- Height not recorded
Travel times
How long the first wave took to reach each part of the ocean, one line for each hour up to 24, estimated from the source and the depth of the sea.
The travel times are computed in your browser, which needs JavaScript.
- 1 to 4 hours
- 5 to 6 hours
- 7 to 14 hours
- 15 hours and more
Computed in your browser the way NOAA’s own travel time maps are: the wave travels at the square root of gravity times the depth, over NOAA’s ETOPO1 depths averaged to a 10 arc-minute grid. Checked against NOAA NCEI’s maps for 21 tsunamis over the first 24 hours, these lines fall within 10 minutes of NCEI’s at half the points compared and within 52 minutes at 9 in 10. They give when the first wave could arrive, not how high it is; bays, harbors and island chains finer than the grid can see it later. Not for use in a warning: see tsunami.gov.
The tsunami
- Date
- August 5, 1927, 21:13:01 UTC
- Source
- Sanriku, Japan
- Cause
- Earthquake
- Earthquake
- Magnitude 6.9, 10 km deep
- Maximum water height
- 0.1 m (0.3 ft)
- Runups recorded
- 5
- Tsunami magnitude (Iida)
- -3.3
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 37.900° N, 142.000° E
The toll
- Damage
- Limited (under about $1 million) with the earthquake or eruption that caused it
Where the literature gives no number, NCEI records a description on a scale of 1 to 4, printed here in its words. Damage is in millions of US dollars of the year of the event, not adjusted for inflation.
What the record says
NCEI’s account, from the sources it cites.
Reference #150:
Hanabuchi 15 cm, Ishinomaki 5 cm, Tsukihama 5 cm. Some damage in Fukushim and Miyagi by shock.
Reference #414:
1927, August 6, 6:14 local time. There was a strong earthquake with source at sea off the coast of Miyagi Prefecture. It was accompanied by a series of aftershocks. It caused a weak tsunami, which was registered only by tide gauges.
Every runup
Nearest the source first. Heights are above sea level at the time; a tide gauge reads half the wave’s full height.
| Where | Country | Km from source | Water height, m | Inland, m | Measured by | First wave, UTC | Deaths |
|---|---|---|---|---|---|---|---|
| Ayukawa | Japan | 62 | Tide gauge (half the maximum wave height) | ||||
| Ishinomaki | Japan | 86 | 0.03 | Tide gauge (half the maximum wave height) | day 5, 21:54 | ||
| Tsukihama | Japan | 88 | 0.03 | Tide gauge (half the maximum wave height) | day 5, 21:46 | ||
| Hanabuchi | Japan | 94 | 0.08 | Tide gauge (half the maximum wave height) | |||
| Miyako | Japan | 194 | Tide gauge (half the maximum wave height) | day 6, 21:52 |
More
Every tsunami in 1927The 1900sTsunamis of JapanThe earthquakeThis day in weather historyAlerts in force
Sources
Tsunami events and runups from NOAA’s National Centers for Environmental Information, Global Historical Hazard Database, cited as NCEI/WDS, doi:10.7289/V5PN93H7. Public domain. Read 2026-09-24. NCEI tsunami event 1578.