Sierras Are Way Overdue for Major, Costly Earthquake And one expert says we need to start preparing By Michael Harthorne, Newser Staff Posted Apr 19, 2016 1:44 PM CDT Updated Apr 23, 2016 4:07 PM CDT 32 comments Comments (Shutterstock) (Newser) – The West is long overdue for a major earthquake that could cause billions of dollars in damage to parts of Nevada and California, the AP reports. Scientists expect a magnitude-7 quake along the eastern front of the Sierra fault system every 30 years or so; there hasn't been one in more than 60. Similarly, a magnitude-6 or greater quake is expected every 10 years on average; it's been 22 years since the last one. In fact, there were seven magnitude-6.5 or stronger earthquakes between 1915 and 1954; but the fault that stretches from north of Reno and Lake Tahoe to south of Yosemite National Park has been quiet since. FEMA estimates a magnitude-6 quake could cause up to $1.9 billion in damage to the Reno and Sparks areas of Nevada and another $590 million in damage to South Lake Tahoe in California. The Nevada Seismology Laboratory's Graham Kent tells the AP the unusually quiet fault system has lulled residents into a false sense of security when it comes to major earthquakes. Instead, he says governments should be using this time to put together plans for both disaster response and economic recovery in the event of a major quake. Earthquake experts are gathering in Reno this week for the annual meeting of the Seismological Society of America.