April 7, 1970 Tsunami: Philippine Sea, Philippines
A tsunami caused by a magnitude 7.3 earthquake began at Philippine Sea, Philippines on April 7, 1970 at 05:34:05 UTC. The water rose as high as 4.27 meters. Its effects were recorded at 3 places. It killed 15 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
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
- April 7, 1970, 05:34:05 UTC
- Source
- Philippine Sea, Philippines
- Cause
- Earthquake
- Earthquake
- Magnitude 7.3, 40 km deep
- Maximum water height
- 4.27 m (14.0 ft)
- Runups recorded
- 3
- Tsunami intensity (Soloviev-Imamura)
- 1
- Tsunami magnitude (Iida)
- 1
- Waters
- Ocean
- How certain
- Probable tsunami
- Source location
- 15.780° N, 121.710° E
The toll
- Deaths
- 15 with the earthquake or eruption that caused it
- Injuries
- 200 with the earthquake or eruption that caused it
- Damage
- Limited (under about $1 million); Moderate (about $1 to $5 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.
On April 7, 1970 at 05:34:05.6 UTC there was a strong earthquake on Luzon, Philippine Islands. The people of the shore towns "saw the sea pushed back saw the water stripped off like a carpet from the shoreline and folded up into the horizon. But the next moment the folded sea unrolled and came rushing back as a wall of water, a sort of tide, a mile-wide torrent that flooded and crashed past the shoreline engulfing trees, boats, huts and beach". Roads split as wide as two feet, water fountained from the deep chasms created, bridges, collapsed. (reference #1187)
The April 9, 1970 issue of the Manila Times Newspaper quoted observers near Dingalan Bay thus: "Then the bay water line receded as far as 70 meters out into the ocean." ..."And then the sea came surging inland, swamping huts built on the shore. He described the incoming waves as taller than a man." (reference #3149)
People along the Baler shore described the tsunami as the sea being pushed back and its water being stripped off like a carpet from the shoreline and folded up in into the horizon. The next moment, the “folded sea unrolled and came rushing back as a wall of water, a sort of tide, a mile-high torrent that flooded and crashed past the shoreline, engulfing trees, boats, huts and beach” (SEASEE, 1985). (reference #10958)
Reference #417 describes the earthquake and lists the tsunami intensity as 1, but does not list any tsunami runup locations.
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 |
|---|---|---|---|---|---|---|---|
| Baler, Luzon Island | Philippines | 16 | 3 | Eyewitness observation of water height | |||
| San Luis, Luzon Island | Philippines | 29 | 4.27 | Eyewitness observation of water height | |||
| Dingalan Bay | Philippines | 55 | Eyewitness observation of water height |
More
Every tsunami in 1970The 1900sTsunamis of PhilippinesThe 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 2020.