Los Angeles Mayor Eric Garcetti has proposed spending billions of dollars to better protect the city against a devastating earthquake by strengthening thousands of vulnerable older buildings and fortifying the city's water and communications systems. A 126-page report released by the mayor on Monday recommends a host of seismic safeguards, including building a solar-powered Wi-fi network that could keep people in touch in an emergency and developing alternative water sources for firefighters, including seawater. "We cannot afford to be complacent," the mayor said, referring to the risk that another major earthquake could hit fault-laced southern California. A 1994 quake in the city's Northridge neighbourhood killed at least 57 people. "All of us are at risk," he said. Scientists have long pondered the potential for the so-called "Big One", a powerful earthquake on the San Andreas Fault that runs across California. The heart of Garcetti's plan, to be submitted to the City Council, would require strengthening dangerous older structures - those constructed before 1980. It would apply to so-called "soft-first-storey" buildings, which are typically wood-framed and have a garage on the ground floor, and more than 1,400 concrete buildings that are considered at risk of collapse. It is estimated that upgrades for "soft-first-storey" structures could cost US$60,000 to US$130,000 per apartment building, though it's uncertain how much of that bill would end up being rolled into tenant rents. Beverly Kenworthy, executive director of the Los Angeles division of the California Apartment Association, which represents owners and developers, said: "Our concerns are not about the mandate, they really are about the ability to comply."