At and near Lisbon, in 1755, some fountains became muddy, others decreased, others increased, and others dried up. At Montreux, Aigle, and other places, springs became turbid.
The baths at Toplitz, in Bohemia, which were discovered in a.d. 762, were seriously affected by the same earthquake. Previous to the earthquake it is said that they had always given a constant supply of hot water. At this time, however, the chief spring sent up vast quantities of water and ran over. One hour before this it had grown turbid and flowed muddy. After this it stopped for about one minute, but recommenced to flow with prodigious violence, driving before it considerable quantities of reddish ochre. Finally, it settled back to its original clear state and flowed as before.[61]
In 1855, at the earthquake of Wallis, many new springs burst forth, and some of these in Nicolai Thale were so rich in iron that they quickly formed a deposit of ochre.
At the time of the Belluno earthquake (June 29, 1873), a hot spring, La Vena d’Oro, suddenly became red.[62]
The following examples of like changes are taken from the writings of Fuchs.[63]
In 1738 the hot springs of St. Euphema rose considerably in their temperature.
During the earthquake of October, 1848, the hot springs of Ardebil, which usually had a temperature of from 44° to 46° C., rose so high that their temperature was sufficient to cause scalding.
At the time of the earthquake of Wallis, in 1855, the temperature of hot springs rose 7°, and the quantity of water increased three times.
During the earthquake of 1835 in Chili, the springs of Cauquenes fell from 118° to 92° F. Subsequently, however, they again rose.
Fumaroles are similarly disturbed. Thus, at the time of the earthquakes of Martinique (September, 1875), the fumaroles there showed an abnormal activity.[64]