Geoscience Reference
In-Depth Information
The 1247 earthquake is the only earthquake before the 19th century that one can
say was certainly felt in England, Scotland, Ireland and Wales. It was particularly
strong, and even damaging, in Wales, and there seems little doubt that this was a
Welsh earthquake and one of the largest known in Wales.
5.2 19 September 1508
The source material for this earthquake has already been published and discussed at
length in Musson (2004) and will be summarised only briefly here. There are only
three sources, none of them contemporary. Two are Scottish and one is English, and
the English one may have used one of the Scottish ones. The combined information
yields the following points:
The earthquake was reportedly felt over all England and Scotland.
People were much frightened.
The shock lasted 6 min.
The earthquake particularly shook churches.
As in the previous case, we have an earthquake with a large felt area, this time
explicitly including Scotland as well as England, plus a description of shaking build-
ings without any mention of damage. It is interesting to note that churches were most
affected; this again might be consistent with the effect of long-period shaking on the
highest buildings around. It would probably be dangerous to try and read much into
the estimate of 6 min duration, as such estimates are usually unreliable. Enormously
exaggerated durations (“the shock lasted for half an hour”) can be interpreted as
referring to the main shock plus several aftershocks. Six minutes is not gross exag-
geration, and may be taken as indicating at least that what was perceived was not a
short sharp shock - again, consistent with a distant event.
The fact that Scottish sources here have prime place does lead one to infer that the
shock was stronger in Scotland than in England. There are not many interpretations
that are consistent with the evidence, slender though it is. (Musson, 1994) treats
this earthquake as a probable Northern North Sea earthquake, analogous to that of
24 January 1927; this possibility is compared to the passive margin hypothesis in
Musson (2004). There is no information forthcoming from Norway, but given the
historical period, this is not very likely anyway.
Probably, of all events in the UK earthquake catalogue, this is the one that con-
forms best to the pattern of Fig. 2. What is missing is any report from Ireland. If it
were known that the earthquake had also been felt in Ireland, the implication that
this was likely to have been a large passive margin event would be strong. Historical
earthquakes in Ireland were investigated 30 years ago by Richardson (1975), and
his report does not include any entry for 1508. No more recent search of the Irish
archives for earthquake data has been undertaken. Considering known sources for
this period, the Annals of Ulster make no mention of any earthquake, but at this
period it is a record of raids and deaths of eminent people (Bale and Purcell, 2003).
Search WWH ::
Custom Search