Bull Earthquake Eng (2013) 11:715–861 DOI 10.1007/s10518-013-9444-5 ORIGINAL RESEARCH PAPER A history of British seismology R. M. W. Musson Received: 14 March 2013 / Accepted: 21 March 2013 / Published online: 9 May 2013 © The Author(s) 2013. This article is published with open access at Springerlink.com Abstract The work of John Milne, the centenary of whose death is marked in 2013, has had a large impact in the development in global seismology. On his return from Japan to England in 1895, he established for the first time a global earthquake recording network, centred on his observatory at Shide, Isle of Wight. His composite bulletins, the “Shide Circulars” developed, in the twentieth century, into the world earthquake bulletins of the International Seismolog- ical Summary and eventually the International Seismological Centre, which continues to publish the definitive earthquake parameters of world earthquakes on a monthly basis. In fact, seismology has a long tradition in Britain, stretching back to early investigations by members of the Royal Society after 1660. Investigations in Scotland in the early 1840s led to a number of firsts, including the first network of instruments, the first seismic bulletin, and indeed, the first use of the word “seismometer”, from which words like “seismology” are a back-formation. This paper will present a chronological survey of the development of seismology in the British Isles, from the first written observations of local earthquakes in the seventh century, and the first theoretical writing on earthquakes in the twelfth century, up to the monitoring of earthquakes in Britain in the present day. Keywords History of seismology · British Isles · John Milne · Robert Mallet · Seismic monitoring · Macroseismology 1Preface In choosing this title for the 14th Mallet-Milne lecture, I am of course calling to mind Charles Davison’s “History of British Earthquakes” (Davison 1924), which for many years was the This paper is released on Open Access under the terms of the CC-BY license. The terms of this do not apply to the illustrations used in this paper, many of which were supplied under academic licenses, or CC-NC-BY licenses. R. M. W. Musson (B) British Geological Survey, West Mains Road, Edinburgh, UK e-mail: [email protected] 123 716 Bull Earthquake Eng (2013) 11:715–861 standard text on the seismicity of the UK. However, all three words of the title come with questions attached, and dealing with them at the outset will serve to outline the scope of this monograph. History, according to the humorists Sellar and Yeatman, is what you can remember. I have suggested before now that all earthquakes are historical. By the time a seismologist hears about one, it’s already over. A volcanologist hearing that Vesuvius is erupting has plenty of time to pack a bag, head for the airport, arrive in Naples and find the eruption is still continuing. An earthquake is over in a minute or two at most, and the best the seismologist can do is visit the ruins and perhaps record the aftershocks. The main event is already in the past. For most people, though, it would be stretching definitions to describe yesterday’s earth- quakes as historical events. For the man in the street, history is something that happened a long time ago. It is the bane of archivists everywhere that while anyone who discovers a letter dated 1762 will immediately recognise it as being of historical interest, a letter dated 1962 will probably be consigned to the bin. This is a significant contributor to the poor survival of documents from all periods—they get discarded before they become sufficiently old to be considered interesting as historical documents. Only those of financial value: wills, title deeds, etc, survive. So is there a date at which history ends and current affairs begin? In seismology there often is. It has been the practice in the UK to treat the start of modern instrumental monitoring as the end of history. Thus all British earthquakes before 1970 are classed as historical, those after as modern—although many twentieth century British earthquakes before 1970 are reasonably well instrumentally recorded. Similar distinctions probably exist in other countries, with different pivotal dates. I will follow the same distinction in this study, but I will carry the history up to the present day, although the main focus will be on the period before John Milne’s death in 1913, the centenary of which this lecture commemorates. The word “British” has other problems. The distinction between England, Britain, Great Britain, the United Kingdom, and the British Isles is a constant source of difficulty to many, and not just to those who live in none of those divisions. Here I intend to use the term “British” in its widest geographical (and not political) sense, to encompass the whole British Isles. I am not one who sees the use of this term as loaded (and I speak as a citizen of the Irish Republic), and the alternative, “Atlantic Isles”, would seem to include at least the Faeroes, if not Iceland and the Canaries as well. Furthermore, for most of the period under discussion, Ireland and Great Britain were part of the same political entity, and to try and exclude Ireland would mean writing Robert Mallet out of the Mallet-Milne lecture, which would hardly do. Seismology is the study of earthquakes, but one can differentiate between theoretical and practical seismology, by which I mean on the one hand, the attempt to understand what earthquakes are and why and how they occur, and on the other hand, the attempt to monitor and measure them. With respect to the present monograph, I focus to a large extent on observational seismology, and in particular, the observation of British earthquakes. Before the twentieth century, earthquake monitoring was restricted for the most part to documenting earthquakes through their felt effects, not always scientifically. Up to 1900, I will consider developments in theoretical seismology in Britain; over this period, the nature and cause of earthquakes was very much in doubt, and it is interesting to trace the evolution of thinking about them; it makes sense to write about what individual scientists thought about earthquake phenomena. 123 Bull Earthquake Eng (2013) 11:715–861 717 After the end of the nineteenth century, I will concentrate almost exclusively on the development of seismology as earthquake monitoring. From the twentieth century on, the development of scientific thinking about earthquakes has been such an international enterprise that it makes no sense to try and distinguish a purely “British seismology”. Regrettably, this means passing over much of the seismological research undertaken by universities in Britain in the twentieth century, which could occupy several chapters. As a result, some important figures like Sir Harold Jeffreys (1891–1989) are largely passed over. Similarly, the history of explosion monitoring is regrettably omitted. One could question whether it was ever possible to isolate British theoretical seismology from that elsewhere. The earliest writers on earthquakes in Britain took their cue from clas- sical authors such as Aristotle and Seneca. In the seventeenth century, the Belgian writer Fromondus (Libert Froidmont 1587–1653) was influential. The earthquake committee of the British Association for the Advancement of Science in the 1840s was informed about inves- tigations in Italy. Robert Mallet was a friend of Alexis Perrey in France, and John Milne was influenced by Ernst von Rebeur-Paschwitz in Germany. It is doubtful if it is possible to be so complete as to mention everyone who has ever written about earthquakes in Britain, so the account that follows is necessarily partial. I have left out, for instance, authors of short papers on earthquakes of a particular county, such as Edward Parfitt’s (1820–1893) account of earthquakes in Devon (Parfitt 1884); Parfitt was the Librarian of the Devon and Exeter Institute. Some writers of now forgotten theoretical pamphlets are also passed over; I have given more weight to those who actually were involved in investigations of British earthquakes. I have passed over rather briefly the work of British seismologists overseas, apart from brief notes on the work done by Milne and his contem- poraries in Japan. Regrettably, this means passing over the work of Richard Dixon Oldham (1858–1936), the first Director of the Geological Survey of India, and the discoverer of the earth’s core. Also, although this monograph is structured largely by devoting sections to particular individuals, there was in reality much overlap—as will be apparent. 2 Earliest British writings on earthquakes: to the end of Aristotelianism The story of writings on earthquakes in Britain starts, perhaps surprisingly, in Iona (Fig. 1). This small island off the west of Scotland is today only reachable by two ferry crossings; a car ferry to Mull and a passenger-only ferry to Iona itself. But as Professor William Kirk, an inspirational figure to Irish geographers, used to remind undergraduates, ideas of centrality depend on where you put the spokes. Ireland and the west of Scotland may seem today like the extreme periphery of Europe, but there was a period when they were the intellectual hub of Europe, a centre of learning, and the base from which Christian missionaries were dispatched to turn back the tide of paganism across the continent (see, for instance, MacCulloch 2010). 2.1 Irish annals The earliest written mention of earthquakes in the British Isles are notes of their occurrence in monastic annals, and the earliest of these refer to earthquakes in Ireland. These are mentioned in Irish annals, but the relationship between the early chronicles is complex and difficult to untangle.