The improvements would particularly benefit areas poorly served by the existing network -- south of the San Francisco Bay Area to north Los Angeles and north of the San Francisco Bay Area, the study's authors said.
"We know where most active faults are in California, and we can smartly place seismic stations to optimize the network," said Serdar Kuyuk, a professor of civil engineering at Sakarya University in Turkey.
Kuyuk conducted the California study while a post-doctoral fellow at University of California, Berkeley.
"There are only 10 stations along the 150-mile section of the San Andreas Fault," he said. "Adding more stations would improve warning for people in these areas, as well as people in LA and the Bay Area should an earthquake start somewhere in between."
While the U.S. Geological Survey/Caltech Southern California Seismic and TriNet Network in Southern California was upgraded in response to the 1994 Northridge quake, the United States is lagging behind Japan and other countries in developing a fully functional warning system, the researchers said.
Japan's existing earthquake warning system performed well during the 2011 magnitude 9 Tohoku-Oki earthquake, they noted.
"We should not wait until another major quake before improving the early warning system," Kuyuk said of California's system.
Kuyuk and Richard Allen, director of the Seismological Laboratory at UC Berkeley, co-authored the study published in Seismological Research Letters.