Sunday, April 15, 2018

The April 15, 1185 Earthquake That Split the Tallest Building In the World, Top to Bottom

Looks like a job for medieval cat bond man!

From The British Geological Society's "The seismicity of the British Isles  to 1600":
This is one of the largest and most interesting earthquakes of the period. The following facts can be gleaned from the sources: it was felt throughout all of England, but especially in the north; it was the worst ever known in England; stones were split (“petrae enim scissae sunt”); stone houses were thrown down; and Lincoln Cathedral was badly damaged (split from top to bottom). The damage to Lincoln cathedral has been debated. “... the extent of the damage is an inference from the other parts of the building which show no vestige of other earlier work. What has survived [of the pre-earthquake building] is the lower central part of the west end and the lower part of its two attached angle towers” (Johns, 1981 pers. comm.. ).

Kidson (1986), however, is dismissive, and supposes that the prime cause of the collapse (probably a vault collapse) was poor construction or design, with failure perhaps being touched off by the earthquake. Intensity cannot be inferred from the damage to Lincoln cathedral; and as Woo (1991) points out, the structure may have been more vulnerable for geotechnical reasons. However, the information that masonry houses were thrown down implies an intensity more than 7 EMS at unspecified locations.

Diceto, writing in London, says that the earthquake occurred in northern regions and that “in some places buildings were destroyed” (Stubbs 1876). There is no particular reason to suppose the epicentre was close to Lincoln; Davison (1931) suggested that this may have been a North Sea earthquake, a possibility also considered by Muss on (1994). However, there are tantalising references to folklore concerning villages completely destroyed by this earthquake in Nottinghamshire.

Two that are named are Raleigh (between Oxton and Southwell), specifically said to have been destroyed in 1185 (Mayfield 1976), and Danetho pe, south of Brough, for which the date of the earthquake is not given (Throsby 1790, also Beresford 1987, who makes no reference to Raleigh in his list of abandoned villages in the county). A further candidate might be Grimston, near Wellow, but the only reference to this having been destroyed by an earthquake is from a personal communication; written sources suggest that Grimston was a victim of the expansion of the lands of Rufford Abbey (Beresford 1987). An epicentre in Nottinghamshire would be entirely consistent with the available information for this earthquake (see Figure 1). Archaeological investigation would be interesting. On the other hand, there is faint reason to suppose that the earthquake was felt in Norway (see Section 3.21), in which case this would suggest it was a North Sea earthquake. What seems evident from the sources is that the level of damage was considerable, suggesting that this must have been one of the largest British earthquakes, with magnitude above 5 Mw....
There is a distinction between tallest in the world (at any given time) and tallest building ever which can make some of the conversation a bit confusing.
Upon completion in 1311 the Cathedral's central spire (159.7 metres (524 ft)) surpassed the pyramid of Giza which had held the record for 3800 years.

The central spire collapsed in 1549 demoting the building in the extant tall buildings list (St. Mary's, Stralsund Germany took over) but it remained the tallest building ever for another 335 years until the Washington Monument was topped at 555 feet in 1884. Five years later Eiffel completed his tower which was almost as tall as the Cathedral and the Monument combined.

Finally, the Skyscraper News entry on the Cathedral:
  • Lincoln Cathedral was commissioned by William the Conqueror in 1072 who wanting to create a show of Norman power in East Anglia commanded the construction of a cathedral on the site of the demolished Anglo Saxon mother church.
  • The first cathedral was completed in 1092 by Bishop Regimus but destroyed by fire in about 1142.[muddled timeline]
  • The cathedral was rebuilt and expanded by Bishop Alexander but collapsed following an earthquake in 1185 whilst there was no bishop thanks to ongoing civil war.
  • Construction on a third cathedral started in 1186 and spanned the period of 100 years until what exists today was more or less built working from the designs of the bishop St Hugh of Avalon.
  • This cathedral had three spires, the tallest of which was the tallest in the world overtaking the record held by the Great Pyramid of Giza. At 160m tall its height was not bested until the construction of the Eiffel Tower in Paris [incorrect, see above]. The spire collapsed in 1549 in a hurricane.
  • The shorter towers also contained spires, both the second tallest in the U.K. They were removed in the early 19th century after their weight, combined with poor foundations threatened to cause these towers to collapse.
  • Removal of the 30.7 metre spires was originally attempted in 1726 but outraged townsfolk besieged the cathedral and in almost causing a riot prevented them being removed where they stayed until 1807.....

A couple weeks later there was a solar eclipse, with the path of totality running not that far north of Lincoln.
Folks were sort of freaked out.