Felt reports and damage accounts for the 1925 moment magnitude 6.2 Charlevoix, Quebec, earthquake

Abstract

The 28 February 1925 magnitude 6.2 Charlevoix Earthquake occurred at 9:19 p.m. local time. The epicenter was beneath the St. Lawrence River in the Charlevoix-Kamouraska area. The shock was felt at more than 1000 km from the epicenter. In the following weeks, dozens of aftershocks continued to shake the area, keeping residents on both sides of the St. Lawrence River on high alert. Damage was reported on both sides of the River in the epicentral zone, as well as in the cities of Québec and Shawinigan. In these areas, chimneys and masonry buildings proved particularly sensitive to the ground vibrations. The 1925 earthquake is one of five known moment magnitude 5.5-7 events that have occurred in the Charlevoix Seismic Zone (CSZ) between 1663 and present. This Open File Report presents the macroseismic information and its ratings on the Modified Mercalli Scale for a total of more than 600 locations in Canada and some 180 in the United States (from NOAA). This report builds on the macroseismic information published in Cajka (1999) and adds descriptive information for each locality where damage occurred. For each location, the felt information is rated on the Modified Mercalli intensity (MMI) scale and tabulated in a Microsoft Excel sheet. Numerous images of clippings of newspaper articles are included and the descriptive text is added to the database. In addition, photographs of the earthquake damage are included. The Open File also provides a GoogleEarth kmz file that allows the felt information reports to be viewed in a spatial tool.