The 1944 San Juan earthquake took place in the province

Provinces of Argentina

Argentina is subdivided into twenty-three provinces and one autonomous city...

 of San Juan

San Juan Province (Argentina)

San Juan is a province of Argentina, located in the western part of the country. Neighbouring provinces are, moving clockwise from the north, La Rioja, San Luis and Mendoza. It borders with Chile at the west....

, in the center-west area of Argentina

Cuyo (Argentina)

Cuyo is the name given to the wine-producing, mountainous area of central-west Argentina. Historically it comprised the provinces of San Juan, San Luis and Mendoza. The term New Cuyo is a modern one, which indicates both Cuyo proper and the province of La Rioja...

, a region highly prone to seismic events. This moderate to strong earthquake (estimated moment magnitude

Moment magnitude scale

The moment magnitude scale is used by seismologists to measure the size of earthquakes in terms of the energy released. The magnitude is based on the seismic moment of the earthquake, which is equal to the rigidity of the Earth multiplied by the average amount of slip on the fault and the size of...

s range from 6.7 to 7.8) destroyed a large part of San Juan

San Juan, Argentina

San Juan is the capital city of the Argentine province of San Juan in the Cuyo region, located in the Tulúm Valley, west of the San Juan River, at above mean sea level, with a population of around 112,000 as per the ....

, 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

Epicenter

The epicenter or epicentre is the point on the Earth's surface that is directly above the hypocenter or focus, the point where an earthquake or underground explosion originates...

 located 30 km north of the provincial capital, near La Laja in Albardón Department

Albardón Department

Albardón is a department of the San Juan Province . It is located in the center south of the same, which emphasizes a desert landscape with mountains and numerous plantations at, highlighting the presence of prestigious wineries known nationally....

. 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

Adobe

Adobe is a natural building material made from sand, clay, water, and some kind of fibrous or organic material , which the builders shape into bricks using frames and dry in the sun. Adobe buildings are similar to cob and mudbrick buildings. Adobe structures are extremely durable, and account for...

 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.

Aid and reconstruction

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

Peronism

Peronism , or Justicialism , is an Argentine political movement based on the programmes associated with former President Juan Perón and his second wife, Eva Perón...

 rule. Colonel Juan Perón

Juan Perón

Juan Domingo Perón was an Argentine military officer, and politician. Perón was three times elected as President of Argentina though he only managed to serve one full term, after serving in several government positions, including the Secretary of Labor and the Vice Presidency...

, later to become president, had met his wife Eva Duarte

Eva Perón

María Eva Duarte de Perón was the second wife of President Juan Perón and served as the First Lady of Argentina from 1946 until her death in 1952. She is often referred to as simply Eva Perón, or by the affectionate Spanish language diminutive Evita.She was born in the village of Los Toldos in...

 (Evita), during fundraising activities to help the victims. After the 1955 coup d'état

Revolución Libertadora

The Revolución Libertadora was a military uprising that ended the second presidential term of Juan Perón in Argentina, on September 16, 1955.-History:...

 ousted Perón, the reconstruction was continued under the de facto President Pedro Eugenio Aramburu

Pedro Eugenio Aramburu

Pedro Eugenio Aramburu Silveti was an Argentine Army General. Born in Río Cuarto, Córdoba on May 21, 1903. He was a major figure behind the military coup against Juan Perón in 1955. He became de facto president of Argentina from November 13, 1955 to May 1, 1958...

.

The earthquake caused many families to scatter in the confusion, and left around 1,000 orphaned children. According to historian Mark Healey, the issues surrounding the orphans and the nearly 100,000 homeless had a profound influence on the shaping of social legislation enacted during Perón's first term as president, two years later.

The modern city

As of 2006, San Juan has a population of around 400,000, and 63% of its approximately 90,000 homes, and 100% of its public institutional buildings, were built under seismic safety regulations

Seismic retrofit

Seismic retrofitting is the modification of existing structures to make them more resistant to seismic activity, ground motion, or soil failure due to earthquakes. With better understanding of seismic demand on structures and with our recent experiences with large earthquakes near urban centers,...

. This, however, leaves more than a third of houses as non-seismic-resistant.

A study of the seismic vulnerability of the city, conducted by the National University of San Juan

National University of San Juan

The National University of San Juan is a public university in Argentina. Its seat is located in the city of San Juan, capital of the province of the same name, in the Cuyo region...

in 2005, showed that 28% of the outlying neighborhoods present medium risk, and 20% of the city itself can be classified as high or very high vulnerability.