DEVELOPMENT OF SEISMOLOGY IN SPAIN IN THE CONTEXT OF THE THREE LARGE EARTHQUAKES OF 1755, 1884 AND 1954 Author(s): AGUSTÍN UDÍAS Source: Earth Sciences History , 2013, Vol. 32, No. 2 (2013), pp. 186-203 Published by: History of Earth Sciences Society Stable URL: https://www.jstor.org/stable/24140011 REFERENCES Linked references are available on JSTOR for this article: https://www.jstor.org/stable/24140011?seq=1&cid=pdf- reference#references_tab_contents You may need to log in to JSTOR to access the linked references. JSTOR is a not-for-profit service that helps scholars, researchers, and students discover, use, and build upon a wide range of content in a trusted digital archive. We use information technology and tools to increase productivity and facilitate new forms of scholarship. For more information about JSTOR, please contact [email protected]. Your use of the JSTOR archive indicates your acceptance of the Terms & Conditions of Use, available at https://about.jstor.org/terms is collaborating with JSTOR to digitize, preserve and extend access to Earth Sciences History This content downloaded from 86.59.13.237 on Thu, 08 Jul 2021 13:49:34 UTC All use subject to https://about.jstor.org/terms DEVELOPMENT OF SEISMOLOGY IN SPAIN DEVELOPMENT OF SEISMOLOGY IN SPAIN IN THE CONTEXT OF THE THREE LARGE EARTHQUAKES OF 1755,1884 AND 1954 AGUSTIN UDIAS Departamento de Geofisica y Meteorologie/ Facultad C. Fisicas, Universidad Complutense de Madrid 28040 Madrid\ Spain audiasva@fis. ucm. es ABSTRACT The occurrence of large earthquakes is in many cases a catalyst for the advancement of seismology. This article examines the influence of the three large earthquakes of 1755, 1884 and 1954, felt in the Iberian peninsula, in the development of seismology in Spain. The 1755 earthquake was the occasion for the establishment of the study of earthquakes as *1 natural phenomena outside of religious considerations and the introduction of modern ideas about the origin of earthquakes. The 1884 earthquake was the first earthquake in Spain subject to a serious and detailed scientific study by three commissions from Spain, France and Italy. This led to the introduction in Spain of modern ideas about the study of earthquakes and their tectonic origin. It showed also the need for installing seismographic Earth Sciences History stations. The 1954 deep earthquake was the occasion for a renewed interest in Spain for Vol. 32, No. 2,2013 seismology, improvements in the seismographic stations and the beginning of international pp. 186-203 cooperation. 1. INTRODUCTION It is an interesting fact that the study of the history of seismology is marked by the occurrence of large earthquakes. Their impact has provided new observations and has stimulated proposals of new ideas regarding their nature and consequences (Bolt 1993, pp. 1-23). In 1760 John Michell (1724-1788) proposed for the first time the fundamental idea that earthquake motion propagates through the Earth's crust in the form of waves. Michell's proposal was motivated by the occurrence of the Lisbon earthquake of 1 November 1755. Seismology was subsequently established as a modern science at the end of the nineteenth century and the beginning of the twentieth century, with the development of the first instruments (seismographs) to detect, measure and record the ground motion produced by earthquakes and with the application of elasticity theory to the propagation of seismic waves (Davison 1927). Throughout seismology's history important contributions have been made after the occurrence of large earthquakes. Robert Mallet's (1810-1881) study of the 16 December 1857 Naples earthquake is considered as marking the beginning of modern seismology. For the first time, he joined the naturalistic description of phenomena with a rigorous physical-mathematical analysis, integrating geology, physics and mathematics in the study of an earthquake. Other examples are the presentation of the elastic rebound theory for the mechanism of earthquakes by Harry F. Reid (1859-1944) after the San Francisco earthquake of 1906 and the development of the theory of free oscillations of the Earth after the large earthquakes of Kamchatka in 1954 and Chile in 1960. In this article I try to follow the development of seismology in Spain in the context of the occurrence of three large earthquakes in 1755, 1884 and 1954 that affected the Iberian Peninsula. The occurrence of these earthquakes occasioned developments that influenced the history of seismology in Spain. As a consequence we can organize its early developments around these three shocks. The main interest in this article is the presentation of the specific developments of seismology in Spain. More general problems of the history of Earth sciences will not be exmined. 186 This content downloaded from 86.59.13.237 on Thu, 08 Jul 2021 13:49:34 UTC All use subject to https://about.jstor.org/terms AGUSTIN UDIAS 2. THE LISBON EARTHQUAKE AS IT AFFECTED SPAIN On 1 November 1755 at about 9.40 a.m. local time, an extraordinarily large earthquake, the largest felt in Europe in historical times, caused heavy damage to the city of Lisbon (for recent overviews see Fonseca 2004, Machete (ed.) 2005, and Mendez-Victor et al. (eds) 2009). Its magnitude has been estimated as between 8 and 9 in the magnitude-moment scale. Half an hour after its occurrence, waves from the tsunami that it generated added to the destruction (see Figure 1). Estimates of casualties in Lisbon buried under the ruins or affected by the tsunami and by the subsequent fires vary between 10,000 and 20,000. The source of the earthquake has been located somewhere offshore from Cape San Vicente. The tectonic structures responsible for such a large earthquake are not yet fully understood and several proposals have been made (Baptista and Miranda 2009). The earthquake was felt over the entire Iberian Peninsula, producing damage in the nearby region of southwest Spain, especially in the cities of Huelva, Cadiz and Seville. It caused 1,276 deaths in Spain, mostly due to the tsunami in the coastal towns of the provinces of Cadiz and Huelva. About 200 people were drowned in the city of Cadiz and about 400 in Ayamonte (Huelva) (Martinez Solares 2001, Martinez Solares and Lopez-Arroyo 2004). This extraordinary event produced an abundant literature published in Spain, especially in Seville (Udias and Lopez Arroyo 2009). Many of the publications were brief popular accounts (most of them anonymous and some were written in verse) about how the earthquake was felt in some prticular localities, or presented religious considerations about the event. These anonymous publications were generally works of only a few pages of a popular character with exaggerated accounts of damage, or extraordinary and curious occurrences during the earthquake. Some assigned the earthquake to a punishment by God and asked for the pardon of sins or gave thanks for the deliverance from the effects of the earthquake. Other publications were extended treatises on the physical, philosophical and religious aspects of the event, written by scientists, philosophers and theologians. In these treatises two main topics were addressed which marked a preliminary approach to the study of earthquakes in Spain. The first was the consideration of the natural or supernatural character of the earthquake and the second the search for its natural causes in terms of the traditional Aristotelian doctrine or of modern ideas of explosive or electrical sources. 1 -, -- " Figure 1. Engraving with an imagined representation of the damage produced in Lisbon by the 1755 Earthquake. 187 This content downloaded from 86.59.13.237 on Thu, 08 Jul 2021 13:49:34 UTC All use subject to https://about.jstor.org/terms DEVELOPMENT OF SEISMOLOGY IN SPAIN 3. NATURAL OR SUPERNATURAL EVENT? Although Medieval natural philosophers and theologians, such as Albertus Magnus and Thomas Aquinas in the thirteenth century, had already interpreted the natural causes of earthquakes according to Aristotelian doctrine, it was common in popular and religious accounts up to the eighteenth century to consider them as God's punishment for the sins of the people (Chester and Duncan 2009, Udias 2009). Immediately after its occurrence the Lisbon earthquake brought this question in Spain to an explicit and intense focus. Many of the anonymous publications that appeared in Seville after the earthquake took it for granted that the earthquake has been God's punishment for the sins of the people (e.g. Anonymous 1755, Anonymous 1756). Two sermons by Francisco Olazaval y Olayzola, Canon of the Cathedral of Seville, both of which were later published, strongly argued this interpretation (Olazaval y Olayzola 1755). He insisted that the many sins of the city of Seville were the cause of this punishment, which God's mercy had prevented from being even greater. The strongest defender of the supernatural character of the earthquake was Miguel de San José (1682-1757), Bishop of Guadix and Baza (Granada), who in a short letter rejected the opinions of those who regarded it as a natural event. He affirmed: "to deny or doubt that earthquakes and other disasters are usually the effect of the wrath of God can be considered as an error in the faith" (San José 1756). He singled out José de Cevallos in his criticism. Similarly, Thomas del Valle (1703-1776), Bishop of Cadiz, expressed the view that God had punished the people of Cadiz for their sins and called for their repentance (Del Valle 1755). This was not only a Spanish Catholic position. In Protestant England the influential John Wesley (1703-1791), founder of the Methodist movement, argued in his sermons that the earthquake was only explicable if it were a divine punishment (Israel 2011, pp. 39-50). On the other side of the debate, there was serious questioning about attributing the earthquake to a direct action by God.