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proportion of wooden buildings, but the stone houses suffered at least as much as
those in Visp. For many other villages that underwent severe damage, the available
information is much more fragmentary. Whereas Visp, Stalden, St. Niklaus and
Naters were described as having suffered enormously, for other villages such as
Grachen, Torbel, Visperterminen and Brig we know of little damage only, due to a
neglect of descriptions. The extent of harm was remarkable, however, and has no
parallels in Switzerland until the present (Fritsche et al. 2006).
4 G.H. Otto Volger's Depiction of the Event
At the time of the 1855 event the German geologist Georg Heinrich Otto Volger
was committed to the study of the causes of seismic phenomena. Born in 1822 in
Luneburg, Volger studied natural sciences in Gottingen and qualified as a lecturer in
1847. He later taught natural history in a monastery in Muri (Aargau, Switzerland),
and in 1851 became a high school-professor in Zurich. Since his student years
in Gottingen he was seriously interested in mineralogy, crystallography and geol-
ogy. Living in Frankfurt between 1856 and 1860, Volger taught at the Senkenberg
Museum. He died in Sulzbach in Taunus on October 18, 1897 (Oeser 2003).
Independently of Robert Mallet (1810-1881) he developed a neptunist theory
of wave propagation of earthquakes, adapted from the idea of the analogy of wa-
ter waves to sound waves (hence the name neptunist). Volger assumed that most
earthquakes in Switzerland were subsidence earthquakes, and were thus caused by
the collapse of extensive hollow strata. The immediate opportunity to validate his
theory was the Valais 1855 earthquake. As Volger reports in his monograph devoted
to this event, he visited the earthquake site immediately after the main shock, col-
lecting reports and observations from the affected population. Furthermore, he also
created a broad correspondence network among people from more distant localities
in order to complete the macroseismic data series for the earthquake area. Volger's
collection of these genuine macroseismic data, complete with his interpretations,
were published in 1858 (Volger 1857-1858).
1
In his conclusions he discusses origin
and occurrence of earthquakes. The detailed description of the earthquake and the
subsequent discussions on earthquake phenomena show how much an anticipated
hypothesis or theory might influence the observation process, as Volger not only
presents eyewitness records, but also selects and comments them or even corrects
them from the viewpoint of his neptunist theory.
His neptunist subsidence theory assumes extensive wash out in the lower strata
of the crust prior to an earthquake. Volger thus starts his discussion of the Valais
earthquake with an account of the weather conditions before the actual event. His de-
scription of the main shock contains clear references to his theoretical explanation of
this event as a subsidence earthquake. The noise that could be heard from the Earth
1
In the first Volume
Chronik der Erdbeben in der Schweiz
(1857), the author gives an historical
survey of the earthquake occurrence in the Alpine zone and in adjacent regions; in the second one
DieGeologievonWallis
(1857) he describes the geology of the respective regions. The third one
Die Erdbeben im Wallis
(1858) deals with the 1855 event.
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