CALIFORNIA, UNITED STATES - Measuring the level of threat posed by severe earthquakes that could bring havoc to southern California should be reviewed, according to scientists who believe the risk could be greater than previously thought. The warning follows latest research from a US geologist who found that two large faults in the region – the San Andreas and the neighbouring San Jacinto fault to its south – might have ruptured together in the past, producing an earthquake that caused damage as far north as San Buenaventura and was felt as south as San Diego. "Looking at old earthquakes in general is really a good way to figure out what faults are capable of doing," said Julian Lozos, assistant professor of geophysics, California State University, Northridge, who conducted the research. Forming the boundary between two plates of Earth's crust, the San Andreas fault runs for around 800 miles (1,300km) through the state of California with its southern section neighbouring the San