March 3, 1844 Tsunami: Dubrovnik, Croatia

1844 Mar 03, 18h 25m. Underground shocks of varying force started to be felt in Dubrovnik at 01h34m on March 2. The sixth shock occurred at 18h25m on March 3. Shocks were felt for 3 seconds. The sea receded from the coast. Note: this reference #2130 also discusses that description of this event and of 1844 Mar 22 (23) event could be the same event. (reference #2130)

1844 Mar 03, 22-23. In the morning of 3 March, the ground lightly trembled for a moment; in the afternoon, the trembling occurred again during 2 s, but this time with a weaker force than before. The sky was clear with a light westerly breeze; the sea withdrew remarkably (Gazzetta di Zara 1844; Allgemeine Zeitung 1844; Perrey 1850; Kispatic 1891–1895; Ambraseys 1962; Soloviev et al. 2000) (Fig. 18), while the values on the barometer and thermometer did not change from the previous day (Gazzetta di Zara 1844; Allgemeine Zeitung 1844; Perrey 1850). It seems striking that, although a number of coeval journals (Gazzetta di Zara 1844; Allgemeine Zeitung 1844; Agramer Zeitung 1844) and nineteenth-century catalogues report on the earthquakes of 2 and 3 March, there is no mention of destruction or casualties. Hence, it seems that the earthquake was rather weak (it is not listed in Herak et al. 1996), so the generation of a tsunami was not very probable. In that case, the report on the regression of the sea, later interpreted as a tsunami, would be in contradiction with the high sea level on the previous day, if the air pressure had not changed. However, the mild weather conditions suggest that the observed very low sea level was caused by a strong anticyclone. The trembling in Dubrovnik continued for several months. According to Perrey (1850), a sequence of earthquakes struck Dubrovnik on 22 and 23 March; on the first day, the sea was high, and the next day, it was remarkably low, although the barometer and thermometer did not change. This description resembles in great detail the reports on the events of 2 and 3 March. It was used by Kispatic (1891–1895) and later by Ambraseys (1962), Karnik (1971) and Soloviev et al. (2000), although we cannot find in contemporary journals any reports on an earthquake in Dubrovnik. However, there are a number of reports (Gazzetta di Zara 1844; Agramer Zeitung 1844) on a strong earthquake (VIII) on 22 March at around 10 am, with its epicentre inland near Omis. It was preceded by a rain and snow storm and a gale. The trembling was also very strong at Split. At the time of the earthquake, violent sirocco was blowing so that the sea was fuming: ‘Sailors in the port (of Split) did not feel the tremor because their ships were moving on wind and waves’ (Zora Dalmatinska 1844). In spite of strong wind gusts and freezing rain, the earthquake was felt on board royal vessels that were at anchor in the harbour of Vis (Gazzetta di Zara 1844). This note may be taken with reserve, having in mind the storm wind and the rough sea. Hence, the reports on harsh weather on 22 March definitely confirm that the earthquakes in Dubrovnik, reported by Perrey and others to have happened on 22 and 23 March, actually refer to the 2 and 3 March events. (reference #9531)

Note: reference #2130 suggests earthquake caused tsunami, while reference #9531 suggest meteorological origin.