About Professor Simon Haslett

My photo
Cardiff, Wales, United Kingdom
Professor of Physical Geography and Pro Vice-Chancellor at the University of Wales and the University of Wales Trinity Saint David.

Thursday, 7 July 2011

A tsunami in Cornwall?

Under two weeks ago on Monday 27th June, news was reported by the media of a tsunami hitting the coast of Cornwall and along the coast of southern England as far east as Hampshire. The height of the wave was estimated to be up to 1m, but many accounts suggest it was much smaller. Fishermen on beaches in Mounts Bay observed withdrawal of the sea before the wave came ashore and made a hasty retreat, which is very sensible.

The only footage I can find of the wave is from an estuary, which may be the Yealm:


Newspapers were quick to quote Dr Martin Davidson from Plymouth who suggested that the tsunami may have been caused by a submarine slide, which is possible. But given the numerous thunderstorms taking place within the region that week, it may be a meteorological tsunami. Indeed, this event is similar to an event that occurred in the region on 18th August 1892; the following is extracted from a scientific paper I co-authored on thunderstorm generated meteo-tsunami published in 2009:

"Haslett and Bryant (2009) present newspaper reports stating that “a series of tidal waves” occurred along the western English Channel coast in the estuary of the River Yealm where “a good deal of damage was done to boats moored in the river” (Penny Illustrated, 1892, p. 6). The Times (1892a) also reports this event in the River Yealm as well as stating that “there was a rapid rise in the River Fowey as a great tidal wave, but this immediately subsided” (p. 4). ...... The Times (1892b) report thunderstorms in the English Channel that day and Davison (1924) considers that they generated the large tsunami-like waves." (from Haslett et al., 2009, Physics and Chemistry of the Earth).

The British Geological Survey have produced a good evaluation report of the event and cite and extract from my paper (Haslett et al., 2009) as evidence for their preferred view that it was a meteo-tsunami.

Therefore, this small tsunami event could have been caused by an undersea landslide or, more likely perhaps, as a meteo-tsunami. It should be possible to analyse the meteorological conditions at the time to establish if that was the cause, but less so if it was a slide. This is an interesting event that highlights our ignorance of and risk from tsunami-like occurrences around the coast of the British Isles.

Less than a month before this event, on 29th May, I gave the Annual Kelliwic Lecture in Cornwall entitled "The Hell of Higher Water: tsunami and the Cornish coast"; I imagine my audience would not have expected a Cornish tsunami in the news so soon after it:
In this lecture I outline the history of tsunami in Cornwall, including the 1755 Lisbon event, but a number others too. Most of this is based on research that myself and co-author Dr Ted Bryant have published over the past 10 years or so. If anyone is interested, the main papers that relate to tsunamis in Cornwall are:

4 comments:

  1. Colin Maclennan24 March 2012 at 11:56

    Hi,
    Just watched your lecture, absolutely fascinating thank you. I've a particular interest, being in my final year of a BSc in Geosciences with the OU, and looking at submarine landslides and tsunami risk to the UK for my final project. One thing which did surprise me was how quickly you discounted the risk of another "Storegga type" slip from the Norwegian margin as dependant on another ice age. I've read that previously, and can easily agree that as the Storegga deposits have already slid, they can't slide again. However there are a number of issues arising here.
    1. The actual area of the Storegga slide was intensively studied in anticipation of the development of the Ormen Lange gas field which sits within the area of the slide, and its this research which has largely driven the above conclusion.
    2. There are however many other fans of ice age deposits around the continental shelf, some of which have given rise to other slides, and some of which may yet be vulnerable. Berndt et al (2009) have written a particularly insightful article on the extant risks and tsunami possibilities.
    3. As you mention in the lecture, the risk of earthquake triggers may be increasing due to isostatic rebound. In addition, the same ocean warming may be destabilising methane clathrates, leaving slopes more susceptible to collapse.
    Being a Scot, I'm obviously going to favour the exploration of risks up here rather than Cornwall, but I do get the impression from my reading so far that the evidence from just one site is being cited by many to dismiss the risk across the entire continental shelf.
    Would be very interested to hear any other views.
    Kind regards,
    Colin MacLennan

    ReplyDelete
  2. Dear Colin, I am aware of the Berndt et al paper, but given the modelled low risk to the UK I don’t tend to mention it, but your point is well made. I accept the methane clathrates too, but again don’t tend to mention it in public lectures – perhaps I should explain it. Ted Bryant and I wrote s short review in our 2007 Journal of Geology paper on potential submarine slide risks offshores southwest Britain, but I’ve done little else on the matter since. Thanks very much for your interest, Simon.

    ReplyDelete
  3. david blacklock27 April 2012 at 16:26

    David Blacklock.
    Newton Ferrers
    Devon
    I have an old newspaper dated 11 January 1924 which carries a report of a substantial tsunami striking the NW coast of urope from South West France to the South and West coasts of Ireland. It also struck the South coasts of Devon and Cornwall causing much damage, but no loss of life. The front page shows photographs of the damage to Torquay seafront, and to Poethleven in Cornwall. In the Gironde area of france it was described as being 12 ft in height, and came in in two waves 30 minutes apart. I have never heard any reference made to this event and finding it reported in a newspaper of the time was quite a surprise. do you know anything o this event?

    Regards
    David Blacklock

    ReplyDelete
  4. Dear David,

    Many thanks for your comment. I am not aware of the newspaper article you refer to and would very much appreciate a copy if at all possible. I have seen reference to an event on that date, but it is usually considered to be a storm - it will be very interesting to read the article.

    Best wishes,

    Simon.

    ReplyDelete