Damage caused by the 1925 Charlevoix-Kamouraska earthquake
Three separate areas experienced severe effects. The first had maximum damage confined to a narrow belt 20 miles long on both shores of the St. Lawrence in the vicinity of the epicentre. In this area, damage at
Baie-St-Paul St-Urbain, Les Éboulements, Pointe-au-Pic, La Malbaie, Tadoussac and villages adjacent to these on the north shore as well as Ste-Anne-de-la-Pocatière, St-Pacôme, Rivière-Ouelle, St-Philippe, St-Denis, and St-Pascal on the south shore, was owing largely to the strength of the tremors aggravated in a few cases by the deep alluvial soil on which the damaged structures were built. The two other damaged regions were in Québec city and in the Trois-Rivières - Shawinigan Falls area where the damage was owing, not so much to the intensity of the shock, as to the unstable nature of the terrain. A few details of the damage at various places are given below.
The town is built on the delta of the Gouffre river. Here there was a general distribution of minor damage. There were fallen chimneys broken windows, overthrown dishes, etc. The Catholic church, a stone structure with a tower 150 feet high, had two of the large bells thrown out of their bearings, and had a cubic yard of stone dislodged from the top of the tower.
The village is eight miles up the Gouffre river from Baie-St-Paul. Broken windows and fallen chimneys were common, though the houses, being of frame construction, were otherwise unharmed. The stone church which had survived the earthquake of 1870 was practically destroyed. The spire was dangerously tilted towards the northeast and finally fell at 3:00 a.m., eleven days after the earthquake (March 11), breaking the telephone line connecting Chicoutimi with Québec. Water and sand oozed from cracks which opened in the frozen floor of the valley between St-Urbain and Baie-St-Paul.
This village is on the north shore of the St. Lawrence, nine miles below Baie-St-Paul. Much of the plaster was cracked and thirteen chimneys fell, mostly toward the northwest. In several cases the walls of stone houses were cracked.
Pointe-au-Pic and La Malbaie adjoin. Damage in these two villages was more severe than elsewhere on the north shore of the St. Lawrence. At Pointe-au-Pic most of the chimneys were broken, fireplace masonry was cracked and twisted, and statues rotated or fell. Foundations here were more solid than at Baie-St-Paul, many being on rock. Had this not been the case, the damage would have been much greater. The main shock was felt by the crew on a morning train approaching Pointe-au-Pic at the time.
This village is built partly on rock and partly on the alluvium at the mouth of Rivière La Malbaie. It affords an excellent example of the difference in damage sustained by structures on the two types of terrain. The jail which was located on alluvium, though massively constructed of stone, was badly cracked throughout.
The old Cabot manor house on the north shore of the St. Lawrence, also of solid stone construction, suffered severe damage. The south wall bulged out, the great chimneys were tilted and the verandah came loose from the wall. The picture shows in-plane shear failure in spandrel beams of a residential masonry house near the epicentral region. Hodgson (1925) states that the house was standing on a deep sand slope. Other buildings in the vicinity were not seriously damaged.
On the other hand, the church which was built upon solid rock was not damaged. The bond between the stone front and the plaster walls remained unbroken. Several stoves were overturned but no fires resulted which was most remarkable considering the circumstances. Many chimneys were "twisted off". That is, they fell in a manner which left the bricks strewn out in a sort of spiral from the foot of the chimney.
Many chimneys were broken and as a rule fell towards the east.
Considerable damage occurred on the south shore of the St. Lawrence River near the epicentre.
This village is on the south shore of the St. Lawrence. Most of the chimneys were thrown down and plumbing was broken. The plaster tops of pillars in the chapel of the college were destroyed. Some monuments in the cemetery were thrown down while many others were rotated. Crockery was broken throughout the village. The snow, which was frozen hard at the time of the shock, was cracked throughout this district. The frozen earth beneath the snow was cracked into huge rectangular grids and buried water conduits were broken.
There was a general destruction of chimneys, and goods were upset or moved along the floor. In one case a heavy safe was shifted more than a foot. The frozen road surface was cracked more or less regularly at distances of 100 feet or less, in some places as close as 15 feet. A great crack opened in the clay where the valley floor rises to the cliff.
Nearly all chimneys in the district were thrown down by the earthquake. The wall of the railway station was thrown out from foundation to roof by the first shock. Between the station and the St. Lawrence three stone houses with walls up to two feet thick were badly damaged.
The church, a fine stone structure built in 1872, was severely damaged: the organ pipes were projected upward and outward into the auditorium, stones were jarred loose from the walls and the great stone chimney crashed through the roof. damage to a church located on thick clay deposits was photographically documented. The out-of-plane failure of the unreinforced masonry (URM) gable of this church, typical for this type of structures, is attributable to the lack/inadequacy of anchorage between the roof and walls and, in this particular case, to the lack of integrity between the wythes of an otherwise thick stone masonry wall. Some in-plane shear cracks in the walls are also visible. Contrary to what is stated in Hodgson (1925), the church was not demolished following the earthquake. Photo by Hodgson (1925).
In the churchyard the monuments were overturned or rotated. Those which fell lay to the southeast. Some fissures in clay deposits were also noticed nearby, including one formed beside the roadway about a mile from the church.
Photos taken a few months after the earthquake and published in Hodgson (1925).
Here the houses were of frame construction and founded upon rock. There was relataively little damage.
This village had few houses. The church steeple was extraordinarily high and was swayed by the earthquake so that the joint between the roof and the wall was chipped. Statues in the church fell southeast.
The village had a fine church which had suffered damage in the earthquake of 1870. The walls, though very thick, were cracked by this earthquake and every statue but one in the building was thrown down. The cost of repairs was said to be $5,000.
The chief damage here was to the Palais Railway Station and to the grain elevators and shipping sheds which border the St-Charles river. The lower town part of Québec City in 1925 showing the location of the grain elevators and train terminal building (Gare du Palais). This photo eloquently testifies to the low population density in the lower part of town at the time of the earthquake. All the agricultural lands shown are now covered by urban developments built mostly on top of the deep soft soils and clay deposits of the type known to amplify earthquake ground motions. Québec City is approximately 150 km from the epicentre of the 1925 earthquake. Photo Canadian National Railways.
The station is of steel and brick construction. This monumental building in the lower part of town was constructed of unreinforced masonry and steel trussed-arches spanning over large open areas. Photo by E.A. Hodgson. The earthquake swayed the steel, breaking many panes of glass in the skylights and battering the top rows of bricks out of the wall in the north end waiting room. While widely reported to have been damaged during this earthquake by local newspapers, the exact nature of the damage suffered by this building is not well documented. It is known that cracking developed above large windows in a waiting room leading to the collapse of five rows of bricks into the concourse. Cracks also developed in many walls, and parts of the ceiling, skylight glass and heavy lights fell down. Photo during repairs by E.A. Hodgson.
The grain elevator and loading sheds are built on fill which was dredged from the river and placed behind a row of piles along the waters edge. The sheds are about 30 feet high. A row of grain galleries on an open steel framework stands above the shed to a height of about 100 feet. The galleries are connected to the elevator by an overhead passageway. In the top of the elevator, there are immense scales capable of handling 6O tons of grain. Clearly these structures tend to be top heavy. At the time of the earthquake the fill yielded and the galleries lurched back and forth shifting the lower ends of the steel supporting columns on their concrete piers and bending the bracing steelwork. Damage to supporting steel column of a grain elevator in the Québec City harbour. The column shifted by approximately 8 centimetres from its foundation due to motion and ground settlement. Many columns were reported to have settled by as much as 9 centimetres. Some other minor damage was reported but most of the facilities survived the earthquake intact. Photo from Hodgson (1925).
Several sections of the concrete ceiling of the sheds were thrown down. Some of the scales in the elevator were thrown from their pivots and fell to the south, others swung back and forth battering the doors. The superstructure of the elevator with its heavy machinery swayed sufficiently to break the reinforced concrete support columns at their junctures with the main building. Less than half a mile from the elevator and shed stands the Chateau Frontenac Hotel. It is built upon a rocky cliff in the central part of the city. Some persons in the hotel did not feel the earthquake at all and none were greatly alarmed by it. The difference between the observed effects at the two locations so close together is due entirely to the difference in terrain.
Damage here was not serious. A water tank supported on steel columns tied into the walls of a factory swayed hard enough to crack the walls. About 25 feet of the top of a 250-foot brick stack was thrown down.
In Shawinigan, approximately 250 kilometres from the epicentre, a few buildings suffered damage. In the absence of reported damage in similar structures between Québec City and Shawinigan, soil-amplification due to local geological conditions are clearly responsible for this damage. Damage was essentially confined to the out-of-plane failure of URM walls. Many stone and brick walls, though well built, were cracked because the buildings were placed on or near the slopes of clay banks. The steel frame of one factory plant, acting as a battering ram under the influence of the earthquake, dislodged portions of the gable ends from the structure.
Damage at St-Marc's church were also reported. The photo shows out-of-plane failure of URM transept wall of St-Marc church in Shawinigan. Gable, window and exterior wythe of lower part of many masonry wall collapsed outwards.
Abbott (1926) who made a survey of the damage at both Trois-Rivières and Shawinigan Falls placed the total loss for both at $17,000.