UNR study: Lessons learned from Wells quake | NevadaAppeal.com

UNR study: Lessons learned from Wells quake

The Associated Press

RENO – The earthquake that caused nearly $10 million in damage to the rural northeast Nevada town of Wells three years ago was a not-so-gentle reminder that big quakes can hit when and where they are least expected, university researchers said Thursday in a new report.

The magnitude 6.0 temblor that struck on Feb. 21, 2008, was the biggest in Nevada in four decades and the only one that large recorded in northeast Nevada in 120 years, according to the new 500-page report by the Nevada Seismology Laboratory at the University of Nevada, Reno.

Located on U.S. Interstate 80 about 60 miles west of the Utah line, Wells is in an area with one of the lowest seismic hazard levels in Nevada, the report said.

“Wells was a bit of a surprise,” Nevada State Geologist Jon Price said.

The U.S. Geological Survey estimates there is a 9 percent chance of a 6.0 or larger earthquake striking within 30 miles of Wells every 50 years.

The probability of the same magnitude quake is “considerably higher” across much of Nevada – an estimated 67 percent in Reno and 70 percent in Carson City, the new study said. It’s even more likely a quake will strike within 30 miles of the Las Vegas Strip than in Wells – a 12 percent chance over 50 years.

“This observation underscores that damaging earthquakes can occur anywhere in Nevada at any time, even when the calculated probability of an earthquake is low,” the study said. “The next damaging earthquake won’t necessarily occur where we think earthquakes are most likely.”

As a whole, Nevada historically has averaged three or four earthquakes per century of magnitude 7 or greater, said Graham Kent, director of the Nevada Seismological Laboratory.

From 1900-1954, seven were recorded with magnitude 6.5 or higher but there have been none since a pair of magnitude 7 temblors struck four minutes apart in the Dixie Valley near Fallon in 1954, he said.

The quake in Wells destroyed three houses. About 80 businesses and government buildings suffered damage, 17 seriously – mostly older brick structures in the downtown area. More than 60 chimneys were damaged throughout the town.

“Unreinforced masonry buildings are extremely vulnerable to damage and failure,” the study said.

Those bricks and other materials falling off building facades posed the greatest risk to humans, although only two serious injuries were reported. The report said that’s why if people are inside when an earthquake strikes, they should stay inside and if they are outside “get away from buildings.”

The overall cost of the disaster in Wells was about $10.6 million, about $8 million of that in the form of direct damage.

Approximately $4.8 million of that was covered by insurance and another $2 million reimbursed through disaster relief and loans. Other costs, including about $300,000 in emergency response, left the community with an uncompensated loss of $3.9 million, the study estimates.

“Earthquake insurance is a good idea,” the authors noted.

The report was written by Craig de Polo, Kenneth Smith and Christopher Henry – research geologists at the UNR lab that is part of the Nevada Bureau of Mines and Geology. They still are examining some of the more unusual findings, such as the inconsistency in the way objects were thrown from walls.

For example, at the town library, books were tossed from shelves running in a north-south direction but not those going east-west. Likewise, in a number of second-story rooms at a local motel, televisions were thrown from northwest-oriented walls but not from northeast-oriented walls.