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Continuous investigation about the behavior of adobe in earthquakes is the basis of the Peruvian code for earth constructions, norms that serve as a reference point in many countries around the globe.

The majority of the Peruvian population live in adobe house and cannot begin to dream of a brick house. Thus, investigation to resolve the reality is of great importance, not only in Peru, but also in those poor countries of the southern hemisphere threatened by earthquakes.  

"The reason to carry out the research is to discover how to reinforce the houses so that they do not collapse and kill the people, so as not to repeat 1970," said engineer Julio Vargas, who has played a key roll during these decades of research.

The Catholic University of Peru (UCP) began investigations after the great earthquake of 1970 that caused some 70,000 deaths. The previous earthquake in 1966 in Lima had alerted the researchers and the earthquake of 1974 confirmed the importance of continuous research. For almost 4 decades the investigators have pursued the theme. This is the secret behind the Peruvian norms.

The investigations were guided during these decades by Julio Vargas, who was the president of the National Institute for Research and Normalization for Housing, as well as professor at the UCP. He said that continuous investigation was not customary in Latin America. "No one had seriously studied this."

Development of the code
There has been a lack of continuity in the interest and dedication of the society and government that tends to obey events - as long as there are no earthquakes interest drops, only to rise again after another tremor or earthquake.

To a great degree, it has been the follow up provided by the private efforts of the UCP and Julio Vargas that has permitted the continuous investigation, that not only created the code, but also continues to analyze and update it.

"Drafts of the codes were ready in 1974," said the engineer, "and were the first steps in a three year process, that eventually achieved the law in 1977."

The code was completed in 1985. This version was included as a chapter about earth construction by the "International Association of Earthquake Engineering of Tokyo", as well as a publication about "Non-engineered Constructions". This code is the basis of the codes of India and Nepal, as well as other Latin American countries.

"In 2007, we are revised the current code," said the president of the governmental commission, Julio Vargas.

Technical observations of the damages
"We learned about the damages both from the laboratory and the field," said Vargas. "There were patterns of cracks in the walls that were repeated. Also, vertical defects in the corners, diagonal defects, and between windows and door."

"With this information we sought solutions. Important is that we understood that the cracks from the actual earthquakes were the same that we encountered in the laboratory tests."

"The displacement is what has to be controlled in order to avoid collapse," according to Vargas, and he emphasized collapse signifies loss of life.

Continuous housing programs
Since 1977 the code as served as a base for various governmental pilot programs. Nevertheless, a long-term response implies continuous housing programs for that part of the population most affected by earthquakes.

In 1986 state financial institutions supported the construction of houses, and through the Banco de la Vivienda, Banco Hipotecario and Banco de Materiales, it was possible to provide differentiated credits (without interest for the rural areas). Many houses were built, an experience that endured 5 years, the period of one government.

After 1990 these financial organisms disappeared, in order to reduce the state apparatus. New adobe houses have not been constructed through governmental intervention, they are only built in a spontaneous manner. This implies that only brick houses are "formally" built. The poor cannot build with brick, but only with available materials, which is clay. Actually, 40% of the population lives in earthen houses, without state intervention, without following the code.