Penylan Seismograph

The Cardiff Naturalists' Society presented "an exceedingly valuable seismograph"[1] to the City in 1909. It was installed at Penylan and was made available to the public under the supervision of the observatory attendant.[2] The Medical Officer of Health, Edward Walford, had overall responsibility for the seismograph and gave a very detailed account of it for the Cardiff Naturalists' Society in 1911.[3]

Walford stated that the seismograph, a Milne Horizontal Pendulum type, was housed in a detached brick building built specially for it at the Meteorological Station, Penylan. He included details of earthquakes recorded by the instrument, at Zanzibar on 13th December 1910 and at Oshima, south of Japan on the 15th June 1911.

The Penylan station appeared in a list of seismological stations of the world compiled by the American Geophysical Union and pubished in July 1921.[4] It was stated that the Cardiff City Observatory seismologic service was inaugurated on December 20th 1909, and the following information was included:

Lithologic foundation: concrete pier, free of floor, on Old Red Sand-stone and Silurian formations.
Equipment: Milne seismograph, E compo
Time service: light eclipsed every hour by an electromagnet controlled by a watch "kept at Greenwich Mean Time."

Sources of Information

  1. Meteorological Observations in the Society's district, 1908. Reports and transactions of the Cardiff Naturalists' Society Vol. 42 (1909), page 14
  2. Cardiff Times 31st July 1909 page 1
  3. Photograph from E.Walford. The Cardiff Seismograph. Reports and transactions of the Cardiff Naturalists' Society Vol. 44 (1911) pages 19-22 (available from Welsh Journals Online)
  4. Bulletin of the National Research Council. A List of Seismological stations of the world, volume 2 part 7 number 15, July 1921, pages 419-420