The Central German Earthquake of March 6, 1872 Das Mitteldeutsche
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Historical Earthquakes in Central Europe Volume I Editors: Rudolf Gutdeutsch, Gottfried Grünthal, Roger Musson ISSN 0378-0864 Abh. Geol. B.-A. Band 48 S. 51 – 109 Wien, August 1992 ISBN 3-900312-83-4 The Central German Earthquake of March 6, 1872 * By GOTTFRIED GRÜNTHAL With 9 + 5 Figures† and 3 Tables Contents Zusammenfassung ..................................................................................................................................................................................... 51 Abstract ....................................................................................................................................................................................................... 52 1. Introduction ................................................................................................................................................................................................. 52 2. Sources ...................................................................................................................................................................................................... 55 2.1. General Evaluation of the State of Historical Sources ...................................................................................................................... 55 2.2. The Main Contemporary Sources ..................................................................................................................................................... 56 2.3. Selection of Usable Information from the Sources and its Representation ....................................................................................... 62 3. Macroseismic Evaluation and Interpretation ............................................................................................................................................... 62 3.1. Source Categories and Information Content of Sources .................................................................................................................. 62 3.2. Intensity Evaluation and Macroseismic Determination of Focal Parameters .................................................................................... 65 Acknowledgements..................................................................................................................................................................................... 67 References ................................................................................................................................................................................................. 67 Annex: Compilation of Reports on the Central German Earthquake of March 6, 1872 (localities in alphabetical order)......................................................................................................................................................... 69 Das Mitteldeutsche Erdbeben vom 6. März 1872 Zusammenfassung Das mitteldeutsche Erdbeben vom 6. März 1872 mit dem Herdgebiet am Ostrand des Thüringer Beckens, Herdtiefe ca. 12 km, erreichte die Maximalintensität VII-VIII der MSK-Skala. Es gehört zu den größten und am besten dokumentierten Ereignissen dieses Gebietes, in dem die seismische Aktivität eher mäßig ist. Darum bildet es für die Erdbebengefährdungsanalyse eine Schlüsselinformation. Zwar gab es zur Zeit des Bebens noch keine Seismographen und keinen Rundfunk, doch bestand im Lande bereits eine gut organisierte Nachrich- tenübermittlung durch Zeitung und Telegraphie. Das öffentliche Interesse an Naturbeobachtungen und Naturwissenschaften war zu jener Zeit offenbar sehr groß. Auf Grund dieser günstigen Umstände konnte der Autor ein umfassendes makroseismisches Beobach- tungsmaterial zusammentragen. Es ist so reichhaltig, dass sich der Isoseistenverlauf und einige Herdparameter des Bebens verhältnis- mäßig gut bestimmen lassen. Darüberhinaus stellen die Dokumente - nach angemessener Quellenkritik - allein schon einen Wert dar, indem sie als Kompilation von Beobachtungsdaten einschließlich deren Interpretation die Art und Weise der makroseismischen Bearbei- tung, insbesondere historischer Beben, demonstrieren. Weiterhin gibt die Arbeit eine Übersicht über zeitgenössische Untersuchungser- gebnisse und Interpretationen des Mitteldeutschen Erdbebens. Die wichtigsten zeitgenössischen Autoren von Arbeiten zum Mitteldeutschen Erdbeben sind v. Seebach, Grebe und Giebel. Ersterer hat eine für damalige Verhältnisse grundlegende - auch wissenschaftshistorisch interessante - Abhandlung über dieses Beben mit vorwie- gend beschreibendem Charakter verfasst. Er veranlasste eine umfassende Befragung u. a. sämtlicher Dienststellen des Eisenbahntele- graphendienstes durch die Versendung vorgedruckter Antwortkarten. Damit nahm er - freilich mit noch unvollkommenen Voraussetzun- gen - ein Verfahren heutiger Erdbebendienste vorweg. Das Ergebnis dieser Befragung bildet den dominierenden Teil der hier vorliegen- den Dokumentation. An zweiter Stelle in der Wichtigkeit stehen Zeitungsmeldungen. Auch Orts- und Kirchenchroniken bilden eine wich- tige Informationsquelle. Es erfolgt eine Klassifizierung der vorliegenden Berichte in Quellengattungen sowie eine Einordnung hinsichtlich ihrer seismologischen Aussagekraft. Insgesamt wurden 564 Einzelberichte aus 408 Ortschaften verarbeitet. In der Dokumentation werden die geschätzte Intensität und die beiden Quellengattungen angegeben. Es werden eine makroseismische Karte des Schüttergebietes des Bebens vorgelegt und ihre Anomalien diskutiert. * Author’s address: Dr. GOTTFRIED GRÜNTHAL, GeoForschungsZentrum Potsdam, Telegrafenberg A26, D-O-1561 Potsdam. † With 9 Figs. as well as the Figs. 1 to 5 according to V. SEEBACH (1873) illustrating his reports on the towns Cheb and Apolda (in the An- nex) which are used here in the original numbering. 51 Abstract The Central German earthquake of March 6th 1872 with the focal area on the eastern rim of the Thuringian Basin, with a focal depth of approx. 12 km, reached the maximum intensity of VII-VIII of the MSK-scale. It belongs to the largest and best documented events in this region of rather moderate seismic activity. It therefore establishes key information for earthquake hazard analysis. At the time of the earthquake seismographs and radio were not yet invented. But there was already a well-organized communication by newspaper and telegraph. Public interest in observation of nature and in natural sciences at that time was well developed. Due to these favourable con- ditions the author was able to compile comprehensive macroseismic observation material. It is so abundant that the course of isoseis- mals and several focal parameters of the event can be relatively well determined. Moreover, the documents themselves - appropriate source critique provided - are of great value. They demonstrate, as a compilation of observational data, including their Interpretation, the macroseismic procedure, especially of historical events. Furthermore, in this contribution contemporary investigation results and interpre- tations of the Central German earthquake are reviewed. The most important contemporary authors of papers on the Central German earthquake are: v. Seebach, Grebe and Giebel. The former wrote a - for the circumstances of that time - fundamental essay of predominantly descriptive character on this earthquake. This paper is also interesting under the aspect of history of science. v. Seebach initiated an extensive enquiry at all the offices of the railway- telegraph-service by dispatching printed reply-cards. Thus, he anticipated - though yet by inadequate means - a procedure used by today’s earthquake services. The result of this enquiry comprises the dominating part of the documentation presented here. The great number of newspaper notices hold the second place of importance. Chronicles of villages, towns and churches also provide an important source of information. There follows a classification of the available reports, according to their origin and according to their seismological evidence. Altogether 564 single reports concerning 408 townships were used. In the documentation the estimated intensity and both classes of sources are indicated. A macroseismic map of the earthquake is presented and its anomalies are discussed. 1. Introduction order tectonic faults strike NW-SE or in the conjugate direction. According to the prevailing NW-SE directed A relatively strong earthquake - for Central European maximum horizontal compressive stress in the crustal conditions - occurred in the most eastern part of Thur- seismogenic depth range (GRÜNTHAL and STROMEYER, ingia on March 6th, 1872, at 5 minutes to 4 p.m. local 1991), N-S and E-W directed faults should be those time. Seismogeographically, the epicentre of this earth- ones with maximum horizontal shear and therefore quake belongs to the Saxothuringian seismic province highly prone to earthquakes. The local focal zone east which represents a singular zone of increased intra- of Gera, to which the 1872 event belongs, is addition- plate seismic activity. Fig. 1 shows how this seismic ally characterized by an intersection of these N-S tec- province fits into the seismicity pattern of Central tonic elements, traceable most clearly as photolinea- Europe. It presents the epicentres of known damaging tions, with a first order NW-SE directed fault (see earthquakes of Central Europe sensu latu. In more Fig. 3). detail, the catalogued earthquakes of the Saxothurin- Since the 1872 earthquake occurred in the centre of gian seismic