The 1944 San Juan earthquake took place in the province of San Juan, in the center-west area of Argentina, a region highly prone to seismic events. This moderate to strong earthquake (estimated moment magnitudes range from 6.7 to 7.8) destroyed a large part of San Juan, the provincial capital, and killed 10,000 of its inhabitants, 10% of its population at the time. One third of the province population became homeless. It is acknowledged as the worst natural disaster in Argentine history.
The earthquake occurred at 8:52 pm on 15 January 1944 and had its epicenter located 30 km north of the provincial capital, near La Laja in Albardón Department. Some 90% of the buildings in the city were destroyed and those left standing suffered such damage that in most cases they had to be demolished. It is considered that the reason for such widespread destruction was the low quality of construction, rather than just the power of the earthquake.
In 1944 many of San Juan's houses were made of adobe and the reconstruction programme prompted the creation of a building code that took into account contemporary knowledge of earthquakes and their effect on buildings. Stronger bricks were used, concrete single-story houses were erected and sidewalks and streets were made wider.
There was some debate as to whether it would be advisable to rebuild the city in the same place, or to take advantage of the situation to move it to a less earthquake prone location. The former alternative was adopted.
At the start of the reconstruction, emergency homes were built for the population with funds from the national state. This was the first large-scale state-directed construction plan in Argentina, the first stages of which occurred under Peronist rule. Colonel Juan Perón, later to become president, had met his wife Eva Duarte (Evita), during fundraising activities to help the victims. After the 1955 coup d'état ousted Perón, the reconstruction was continued under the de facto President Pedro Eugenio Aramburu.