Historical Seismograms - Evidence from the AD 2000 Izu Islands ...

~~ ~~484 G. Neilson and P. W. BurtonTable 1. The Locations of Some Historical Seismological Observatoriesin the British IslesStation Name Latitude Longitude Elevation(” w> (4ABE Ab erdeen 57.217 2.167 53BID Bidston 53.401 3.072 54DUR Durham 54.767 1.583 103EDI Edinburgh 55.925 3.184 131ESK Eskdalemuir 55.312 3.206 263JRS Jersey 48.192 2.099 53KEW Kew 51.468 0.313 6OXF Oxford 51.767 1.250 61PA1 Paisley 55.846 4.431 31RTH Rathfarnham (Dublin) 53.300 6.283 52SHl Shide 50.688 1.286 15STO Stonyhurst 53.844 2.470 111WBR West Bromwich 52.517 1.983 156The first two decades of the 20th century saw the addition of more stations in bothBritain and Ireland, the most important of which was probably West Bromwich.This observatory was established by J. J. Shaw, primarily to test instruments that hehad built or modified. The original instrument used to equip the British Associationobservatories was the Milne horizontal pendulum (Milne, 1906). The performance ofthis instrument was limited owing to its lack of damping. Shaw introduced dampingto the Milne design and increased its gain, thereby greatly enhancing the usefulnessof these instruments (Shaw, n.d.).Following a series of rather large earthquakes that were felt in Jersey during the1920’9, a station was established at Maison St. Louis, St. Helier, Jersey, in 1935.A station had been established at Durham by E. F. Baxter a few years previously,also with the intention of studying local earthquakes. Unfortunately, it was notpossible to equip either station with an instrument of short enough period to makethem suitable for such studies.During World War 11, Kew Observatory was used to monitor bombing, especiallythe V1 and V2 attacks in 1944.After the war new stations were not installed in the British Isles until the 1960’s’when organizations such as the United Kingdom Atomic Energy Authority and theInstitute of Geological Sciences (now the British Geological Survey) installed severalhigh-gain modern instruments, recording on magnetic tape, at various sites in theBritish Isles.3. History of Individual British Seismological Observatories3.1. BidstonThe first instrument in operation at Bidston was a Darwin bifilar pendulum, thereadings from which were first published in the British Association Report for 1898.By the year 1901 a Milne instrument also had been installed. A vault was speciallyconstructed in the observatory to house the instruments. The vault contained twopiers on which the seismographs rested, one made of brick and the other a large,cement-filled drainpipe.