August 20, 1823 Tsunami: Dubrovnik, Croatia

1823 Aug 20. A strong earthquake occurred in Dubrovnik which was preceded by an atmospheric flash of the type of a meteorite having fallen in the sea. The sea in Dubrovnik recede from the coast almost for a mile and then returned with a great force. Waves were noted in Messina. (reference #2130)

1823 Aug 20. Ragusa and in Turkish Bosnia. A severe shock. The sea retired nearly a mile from the coast. (reference #497, #1879)

1823 Aug 07, 20. In August 1823, a series of earthquakes affected Dubrovnik (Kispatic 1891–1895). The strongest one (VII MCS) was on 7 August at 5 o’clock in the morning. Luka Stulli, a physician, scientist and writer, wrote a detailed report (Stulli 1832; Kispatic 1891–1895) that was sent to the authority at Zadar: ‘The trembling was vertical and very violent, especially towards the end. The morning could not have been more mild and calm than it was. At sea one could not see any of the phenomena that are observed before or after the earthquake; only fishermen who were in their boats near the coast saw at the time of the earthquake fish come to the surface, many of the jumping out of water and turning over’. Franz Petter, an Austrian professor on duty in Dalmatia, was in Dubrovnik when violent cracking woke him up, making him never to forget the morning of 7 August 1823. In his book (Petter 1857), he writes ‘The sailors that were asleep on their boats said that they clearly felt the shock’. In the nineteenth- and twentieth-century catalogues, the sea effects were not linked to this event. However, all the catalogues note a tsunami that had apparently occurred on 20 August. At Dubrovnik, strong shaking was preceded by appearance of a flying meteoroid that fell into the sea; the sea retreated a mile from the coast (Perrey 1850; Mallet and Mallet 1858). This information originated from contemporary journals published in western Europe, and it was later incorporated in modern catalogues, either directly from the originals or through the nineteenth-century catalogues (Fig. 15). It is interesting to note that Kispatic (1891–1895) also reports the 20 August tsunami, but only with reference to Perrey (1850); although there are several first-hand reports on the 7 August earthquake, none of them mention the event of 20 August cited by Perrey and the others. In addition, Perrey (1850) writes that another tsunami of the same description as the above occurred in October of the same year, but Kispatic (1891–1895) and Soloviev et al. (2000) argue that it is probably the same event. Hence, we are inclined to believe that the only reliable event is the one of 7 August, especially because the other two earthquakes are not listed in the Croatian earthquake catalogue (Herak et al. 1996). However, the detailed coeval descriptions of the sea phenomena refer to a seaquake and not to a tsunami. (reference #9531)