September 11, 1921 Tsunami: Java, Indonesia
A tsunami caused by a magnitude 7.5 earthquake began at Java, Indonesia on September 11, 1921 at 04:01:38 UTC. The water rose as high as 0.1 meters. Its effects were recorded at 3 places in at least 2 countries.
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
The tsunami
- Date
- September 11, 1921, 04:01:38 UTC
- Source
- Java, Indonesia
- Cause
- Earthquake
- Earthquake
- Magnitude 7.5
- Maximum water height
- 0.1 m (0.3 ft)
- Runups recorded
- 3
- Tsunami intensity (Soloviev-Imamura)
- -2
- Tsunami magnitude (Iida)
- -2.3
- Waters
- Ocean
- How certain
- Definite tsunami
- Source location
- 11.000° S, 111.000° E
The toll
The record gives no deaths, injuries or damage for this tsunami.
What the record says
NCEI’s account, from the sources it cites.
September 11, 1921, 11:00 [local time]. There was a strong earthquake with source south of Java Island. A small tsunami arose. It was noted at Parang Tritis and was registered by the tide gauge at Tjilatjap, beginning at 12:15 with a maximal amplitude of 10 cm. (reference #414)
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 |
|---|---|---|---|---|---|---|---|
| Parang Tritis | Indonesia | 338 | Eyewitness observation of water height | ||||
| Tjilatjap, Sumatra | Indonesia | 422 | 0.1 | Tide gauge (half the maximum wave height) | |||
| Spratly Islands | Vietnam | 2,180 | Eyewitness observation of water height |
More
Every tsunami in 1921The 1900sTsunamis of IndonesiaThe 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 1490.