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

The Ma‘laga Earthquake of 9 October 1680 209His rule represents the darkest period of the Austrian dynasty in Spain. Frequentperiods of famine and widespread plagues in 1647-52 and 1676-85, together withemigration to America resulted in a decrease of the population between 1590 and1717 from 8,485,000 to 7,500,000 in all Spain. The city of MAlaga, an active harbourhad at that time an estimated population of about 18,000, while that of the provincewas about 95,400. Estimations of the population of the area, town by town can beobtained from the different surveys made in 1594, 1646, 1694 and 1768 (Anonymous,1829).To evaluate the extent of the damage and to determine the focal parameters ofthis earthquake information has been procured from historical sources. This informationprovides knowledge of the effects of this earthquake on persons, buildingsand the terrain about the epicenter. For this purpose a comprehensive search forhistorical sources and their careful evaluation has been made. From the obtainedmacroseismic data, an intensity map has been drawn. Focal parameters such asmaximum intensity, macroseismic epicentral location, magnitude, and seismic momenthave been estimated from the intensity data.2. Historical SourcesAn extensive search for documents relative to this earthquake was made in librariesand archives. The result is a collection of written contemporary documentsof different types. The first type includes eleven published accounts describing thedamage experienced in MBlaga, Sevilla, Cbrdoba, Jaen, Antequera, Madrid, andValladolid. These can be classified under the heading of “Relaciones” (Relations) aword that appears in most of the titles. Although, they are written for the generalpublic and, in general, their style is embellished with frequent figures of speech andexaggerations, some of these documents contain very detailed information, specifyingnames of villages, of the damage to houses, churches and other buildingsand the number of casualties. A second type of sources are ecclesiastic and civil“Memoriales y Actas” (Memorials and Acts) found in cathedrals, churches and cityhalls, most of them in nianuscript form; because of their official character, this typeof document contains the most reliable information. To find these documents thearchives of cities and towns of Andalucia have been consulted. A third source ofinformation is contemporary publications outside Spain in which this earthquake ismentioned with some detail. The most extensive account is given in the Gazette deFrance n098 (1680), which also relates unusual storms and floods in Spain in thesame year. R. Hooke’s account of the earthquake is practically a translation of theFrench text. Shorter relations are included in German and Dutch texts. Althoughall these accounts are based on Spanish sources, especially the “Relaciones” and donot add any new information, they are of interest since they indicate the importanceof this event. Secondary sources have been also consulted.A list of the most important contemporary documents divided in the three mentionedcategories and secondary sources is given in the Appendix I. Not all documentsare independent firsthand accounts and there is considerable dependence ofsome documents on others. This must be taken carefully into consideration at thetime of assessing the intensities. For example a document printed in Sevilla willgive firsthand data from that city and copy from other documents the damage ofother cities and towns.