Major quake likely once every 300 years in Reno area

Sunday, Oct. 17, 1999 | 10:35 a.m.

The last earthquake of such force shook May 29, 1860, just north of Interstate 80 east of Sparks.

Such major earthquakes are capable of widespread, heavy damage. The magnitude-6.7 Northridge temblor in 1994 killed 67 people and caused $20 billion in damage in the Los Angeles area.

"Since it is a random process, you can't say we are due or overdue," said John Anderson, director of UNR's seismology lab and report co-author.

"We have a fairly big uncertainty. At one end (a 7.0 temblor) would occur once every 1,000 years and at the other end every 80 years."

The study examined an area of northwest Nevada around Reno bounded by Gardnerville, Stead, Fernley and the California line.

Anderson said little is known about the 1860 quake east of Sparks. "We know it was fairly strong and felt fairly widely," he said.

Scientists have recorded four earthquakes above 7.0 this century in northern Nevada, making the state the third most seismically active in the nation behind Alaska and California.

But those temblors struck sparsely populated, rural areas, and did not result in deaths or widespread damage, Anderson said.

Nevada's last quake of such force - one of magnitude-7.2 - occurred in the Fairview Peak area east of Fallon in 1954.

Large earthquakes, magnitude-6.0 to magnitude 6.9, occur once every 10 years in Nevada. The most recent was the magnitude-6.0 Double Spring Flat quake, which occurred on Sept. 12, 1994 south of Gardnerville.

State geologists have said the Reno area has a 34 percent to 98 percent chance of a magnitude-6.0 quake in the next 50 years.

They said most major earthquakes occur in the northwestern part of the state, but Southern Nevada is not immune from seismic activity.

Earthquake-related forces have helped make Nevada the most mountainous state in the lower 48.

No one has been killed in a Nevada earthquake, but records only go back to the 1850s.