Consequences of Small-to-Moderate (Mw 4.0–5.5) Earthquakes: Examples from the Fennoscandian Shield in 1882 and 1904

Abstract We explored the hitherto unknown consequences of the earthquakes of 23 June 1882, Mw ∼4.2, and 23 October 1904, Ms 5.4, in the Swedish and Finnish territories situated on the Fennoscandian Shield. Contemporary newspaper accounts were retrieved from a preexisting report for the 1882 earthquake and from microfilmed and digitized newspapers for the 1904 earthquake. We visited the National Archives of Sweden and Finland, along with a Swedish archive of trade and industry, to explore official series of administrative entities, correspondence between authorities, and an accident investigation report. The findings indicate that unreinforced masonry chimneys and stoves, and tiled stoves in particular, were affected at distances of up to 300–400 km from the earthquake epicenter, posing a fire hazard. Other vulnerable structures affected by ground shaking in 1904 were a quay wall under construction and previously dilapidated medieval churches. Reports were found of a few serious injuries caused by jumping out of windows, and many slight ones, such as contusions, bruising, and burns, mainly caused by a panicked rush in churches and due to postearthquake fires. The findings imply notable total losses, including a substantial number of costs for minor damage paid by property owners and merchants over a large area in 1904. An insurance company paid compensation to a Swedish parish whose church burned down in a postearthquake fire. A defect in the flue leading from the heating appliance in the church caused by earthquake ground shaking was considered the likely cause of the fire, although it could not be established with complete certainty. Information obtained from newspapers and archives overlapped in many cases, but archival documents provided additional details. Some local newspapers also provided more information from their circulation areas than did regional and national newspapers.