The study of the earthquakes which occurred at border regions was the subject of the CEC project RHISE. In this context, the Eastern Alps area is interesting for the presence of different nations and rulers through history.
In the time window 1670-1700 high seismic activity was observed in the Italian territory, including some notable earthquakes in the Eastern Alps. In addition, the study of the seismicity of this time window is particularly stimulating because of the earthquake of December 4, 1690 located in the Villach area. As no strong events are reported after 1700 in this area (Fig. 1), the 1690 earthquake may offer interesting suggestions also for understanding the 1348 earthquake, usually located in the same area (Hammerl, 1994).
The 1690 earthquake is better known in the Austrian territory, where it caused damage (Eisinger, 1991), but it seems to have left no traces in northern Friuli (Slejko and Cergol, 1991), about 50 km from the epicentral area.
The lack of information on the effects of the 1690 earthquake on the Italian territory is not yet adequately explained and remains a crucial point for a global comprehension of the event. In order to better understand the possible causes of these circumstances, this study examines the information coming from the sources of the main seismological compilations and some archival sources for the events of the time window 1689-1700, which could have affected the Friuli area. One of the problems is to understand if the lack of sources for this area applies only to the 1690 earthquake or if it is common for all events of that period.