1929 Grand Banks Tsunami



On November 18, 1929, at 017:02 Newfoundland time, an earthquake occurred of the coast of Grand Banks, Newfoundland. A tsunami was triggered by a sub-marine landslide and the earthquake, which had a Richter magnitude of 7.2 with an epicenter of 44.5°N, 56.3°W. The tsunami caused $400,000 in damage and killed 29 people, the highest death toll attributed to an earthquake in Canada.

The most damaging factor in this event was the sub-marine landslide. The landslide added to the size of the tsunami and damaged many kilometers of 12 transatlantic telegraph cables. The majority of the monetary damage was due to repair costs of the damaged transatlantic cables. Unaware of the danger coming from the sea, the communities of Burin Peninsula, Newfoundland, suffered heavy damages and loss of 29 people. The tsunami was registered as far as South Carolina and Portugal.

In 1952 American scientists from Columbia University put together the pieces of the sequentially broken cables that led to discovery of the landslide and the first documentation of a turbidity current. Scientists are looking at layers of sand believed to be deposited by other tsunamis in an effort to determine the occurrence rates of large earthquakes. One sand layer, thought to be deposited by the 1929 tsunami, at Taylor's Bay was found 13 cm below the turf line. The occurrences of large tsunamis, such as the one in 1929, are dependent upon deposition of sediments offshore because it was the landslide, which made the tsunami so powerful. The deposition of such a large volume of sediments will take awhile before there is enough to for an underwater landslide of size as in 1929.

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