Tsunamis in 842

October 24, 842 Tsunami: Channel Islands, England, United Kingdom

October 24, 842 · Very doubtful tsunami

A tsunami caused by an earthquake began at Channel Islands, England, United Kingdom on October 24, 842. Its effects were recorded at 2 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

Tsunami warnings in force

The tsunami

Date
October 24, 842
Source
Channel Islands, England, United Kingdom
Cause
Earthquake
Earthquake
The earthquake
Runups recorded
2
Waters
Ocean
How certain
Very doubtful tsunami
Source location
49.500° N, 2.500° W

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.

October 24, 842. Channel Islands (49.5 N, 02.5 W) and northern France. Local earthquake. The shock threw down the monuments... and also engulfed the seashore of the neighboring continent. (reference #43)

Every runup

Nearest the source first. Heights are above sea level at the time; a tide gauge reads half the wave’s full height.

WhereCountryKm from sourceWater height, mInland, mMeasured byFirst wave, UTCDeaths
Channel Islands, EnglandUnited Kingdom23Eyewitness observation of water height
Northern FranceFranceEyewitness observation of water height

More

Every tsunami in 842The 800sTsunamis of United KingdomThe 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 67.