June 12, 1978 Tsunami: Sanriku, Japan

Name: June 12, 1978 Tsunami: Sanriku, Japan
Start: 1978-06-12
Location: Sanriku, Japan

June 12, 1978 · 0.6 m · 28 deaths · $865 million · Definite tsunami

A tsunami caused by a magnitude 7.7 earthquake began at Sanriku, Japan on June 12, 1978 at 08:14:26 UTC. The water rose as high as 0.6 meters. Its effects were recorded at 31 places. It killed 28 people, counting the earthquake or eruption that caused it.

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

Tsunami warnings in force

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: June 12, 1978, 08:14:26 UTC
Source: Sanriku, Japan
Cause: Earthquake
Earthquake: Magnitude 7.7, 44 km deep
Maximum water height: 0.6 m (2.0 ft)
Runups recorded: 31
Tsunami intensity (Soloviev-Imamura): 0.5
Waters: Ocean
How certain: Definite tsunami
Source location: 38.190° N, 142.030° E

The toll

Deaths: 28 with the earthquake or eruption that caused it
Injuries: 1,000 with the earthquake or eruption that caused it
Damage: $865 million with the earthquake or eruption that caused it
Houses destroyed: Very many (over 1,000) 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.

On June 12, 1978, at 17:14 [local time] a strong earthquake of 7.4 magnitude caused extensive destruction in the northeastern part of Honshu. Its epicenter was located in Miyagi Prefecture. Particularly severe destruction was observed in Sendai. As a result of the earthquake 28 people died and nearly 10,000 were injured. Moreover, a tsunami generated by the earthquake caused panic among the people for some time. However, in Onagawa, close to the source, the height of the wave did not exceed 1 m and the tsunami warning was soon withdrawn. Damage caused by the tsunami was not observed. A tsunami generated by the earthquake was recorded by many tide gauges in Japan . All tsunami records from all tide gauges show the tsunami began with a rise in water level. (reference #417)

Reference #150 lists the Onagawa tsunami wave height as 112 cm [amplitude 56 cm].

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	Measured by	First wave, UTC
Enoshima	Japan	44	0.22	Tide gauge (half the maximum wave height)
Ayukawa	Japan	48	0.2	Tide gauge (half the maximum wave height)
Onagawa	Japan	57	0.58	Tide gauge (half the maximum wave height)
Shirahama	Japan	65	0.3	Tide gauge (half the maximum wave height)
Tsukihama	Japan	66	0.35	Tide gauge (half the maximum wave height)
Ishinomaki	Japan	71	0.24	Tide gauge (half the maximum wave height)
Miyato	Japan	77	0.18	Tide gauge (half the maximum wave height)
Kesennumagyoko	Japan	87	0.6	Tide gauge (half the maximum wave height)
Sendaishinko	Japan	88	0.3	Tide gauge (half the maximum wave height)
Shiogama	Japan	88	0.21	Tide gauge (half the maximum wave height)
Ofunato	Japan	95	0.24	Tide gauge (half the maximum wave height)
Matsukawaura	Japan	101	0.1		day 12, 08:54
Somako	Japan	103	0.1	Tide gauge (half the maximum wave height)
Kamaishi	Japan	120	0.24	Tide gauge (half the maximum wave height)
Miyako	Japan	162	0.14	Tide gauge (half the maximum wave height)
Onahama	Japan	172	0.15	Tide gauge (half the maximum wave height)	day 12, 09:21
Hitachiko	Japan	225	0.18	Tide gauge (half the maximum wave height)
Oaraiko	Japan	243	0.17	Tide gauge (half the maximum wave height)
Hachinohe (Kensetsukyoku)	Japan	262	0.26	Tide gauge (half the maximum wave height)
Hachinohe	Japan	264	0.22	Tide gauge (half the maximum wave height)
Kashima	Japan	277	0.16	Tide gauge (half the maximum wave height)
Hakodate	Japan	407	0.1	Tide gauge (half the maximum wave height)
Ooarai-Mera	Japan	412	0.16	Tide gauge (half the maximum wave height)	day 12, 09:14
Mera	Japan	413	0.11	Tide gauge (half the maximum wave height)
Urakawa	Japan	446	0.12	Tide gauge (half the maximum wave height)
Hiroo	Japan	468	0.13	Tide gauge (half the maximum wave height)
Tokachiko	Japan	470	0.17	Tide gauge (half the maximum wave height)
Muroran	Japan	471	0.14	Tide gauge (half the maximum wave height)
Tomakomainishiko	Japan	495	0.12	Tide gauge (half the maximum wave height)
Kushiro	Japan	567	0.17	Tide gauge (half the maximum wave height)
Hanasaki	Japan	639	0.11	Tide gauge (half the maximum wave height)

Every tsunami in 1978 The 1900s Tsunamis of Japan The earthquake This day in weather history Alerts 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 2105.