August 12, 1870 Tsunami: Sydney Harbor, Australia
A tsunami of unknown cause began at Sydney Harbor, Australia on August 12, 1870.
Where the waves reached
The source of the tsunami. No runup with a place is recorded for it.
- 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
- August 12, 1870
- Source
- Sydney Harbor, Australia
- Cause
- Unknown
- Runups recorded
- 0
- Tsunami intensity (Soloviev-Imamura)
- -1
- Waters
- Ocean
- How certain
- Very doubtful tsunami
- Source location
- 33.800° S, 151.300° 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.
August 12-22, 1870, unusual fluctuations in the sea level were recorded at Sydney. These fluctuations were particularly strong from 17:00 on the 17th to 16:00 on the 18th [local time]. (reference #415)
Reference #2783 lists tide gauge observation in Sydney (?)
More
Every tsunami in 1870The 1800sTsunamis of AustraliaThis 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 1015.