DN3 : ( Defense against natural disasters ) . The Army should always be ready to help the civil population in case of disaster . This includes preventive measures . For example , between August and November , military forces are sent to Mexican coastal areas to aid the public in the event of hurricanes or floods . For the Mexican people , the DN3 plan is the most important peacetime operation of the Army . The Army provides food , shelter , medicine , and medical services to the people who need them . This also includes reconstruction of roads and communication services . Because calling the implementation DN3 plan is an acceptance of severe problems , the DN3 plan was not invoked in the 1985 Mexico City earthquake that left large areas of Mexico City in ruins , since the authorities did not want to recognize there was an emergency in the capital , while the army was called to the city , it was just a peacekeeping force . This later became a severe questioning on the government . The Mexican Army provided aid to the US following Hurricane Katrina . More recently , the DN3 plan was invoked in 2009 when an epidemic of swine flu threatened the population and in 2010 after the states of Veracruz , Tabasco , Nuevo León , Chiapas , Oaxaca and Guerrero were severely affected by floods caused by a number of hurricanes and tropical storms
1985 Mexico City earthquake
1985 Mexico City earthquake
Mexican Armed Forces