Christchurch Mayor Bob Parker has requested the army to help provide safety and security in the city in the wake of the country's most damaging earthquake since the 1931 Napier disaster. He also asked people to conserve water and keep boiling water for drinking, not to flush the toilet unless necessary, and not to ''rubberneck'' because it was important roads were clear for vital services.The mayor urged people to check on their neighbours. "The most important thing is that there has been no loss of life.''