La Verne Magazine
Summer 2003

The Shaky Truth About La Verne

by Tim Tevault
photography by Liz Lucsko

Two movers and shakers of the geology world, David D. Oglesby, assistant professor of geophysics at the University of California, Riverside, and Douglas M. Morton, adjunct professor of geology, UC Riverside, are leaders in the study of regional fault lines.

A ticking time bomb is ready to go off underneath the city of La Verne that will leave the town looking as if a terrorist had struck. Alarms will sound, and people will panic. Dogs will howl, and people’s everyday lives will come to a screeching halt. This catastrophic event could happen right this instant, as you are reading this magazine. No, it is not an actual bomb being dropped on La Verne and its residents, but rather an earthquake of magnificent proportions in one of many local faults, waiting to be set free.

What many do not know is that La Verne is surrounded by three minor faults, each capable of producing a tremor larger than a magnitude of 6.0. This, coupled with the San Andreas Fault to the north, which could produce an earthquake of 8.0 magnitude, is a scary thought. According to Dr. David Oglesby, assistant professor of geophysics at the University of California, Riverside, La Verne is “sandwiched” because the still-growing San Gabriel Mountains are being “squished” against the valley. La Verne also lies on a thrust fault, among others, in which one side of the fault is sliding in a downward diagonal direction, and the other is sliding in an upward diagonal direction. La Verne is on the side going down. “In general, the biggest earthquakes occur on thrust faults,” says Oglesby, who has a Ph.D. in physics and grew up in Claremont. “Worldwide that is true; in Southern California, that’s not true because the San Andreas fault is so big.” The city is also built on an alluvial fan. According to Oglesby, this is not an enviable position to be in, because “the unconsolidated materials really amplify seismic waves.”

The strongest fault closest to home for La Verne residents is the San Jose fault, a strike-slip fault that last shook the Inland Empire February 1990. This tremor, misnamed the “Upland Quake,” because of its Padua Hills area epicenter, was a magnitude 5.4 and caused nearly 40 minor injuries in the area, in addition to considerable damage. The San Jose fault also finds its way through nearby Pomona and Claremont, and could potentially create a 6.5 magnitude monster.

The Sierra Madre fault poses a threat to northern La Verne residents and could produce an earthquake measuring up to 7.0 on the Richter scale. The fault runs through the foothill communities of Sierra Madre and Monrovia and continues closer to home, extending through Glendora, La Verne and Claremont. Equally as lethal is the Cucamonga fault, which essentially picks up where the Sierra Madre fault leaves off, around the foothills of La Verne and Claremont, and continues through Upland and into Rancho Cucamonga. This fault could also produce a 7.0 earthquake.

And of course, there is the mother of all faults in California—the San Andreas fault. Because of its size—it stretches from Northern to Southern California—it is capable of producing up to an 8.0 earthquake. Oglesby says scientists do not know exactly what an earthquake of this magnitude will do to the area. “Honestly, we have not had an earthquake that big in a major metropolitan area like Los Angeles, ever,” he says, adding scientists can only use the Northridge quake of 1994 as a guide for the future. “There are so many variables we don’t know about. This is one of those situations where nature does the experiment for us.”

Although the fault is on the north side of the San Gabriel Mountains, the seismic waves of an earthquake that large would no doubt be felt by people as far south as Mexico to as far north as San Francisco. “We’ve actually been surprised by how far earthquakes have been felt. The magnitude alone doesn’t tell you how strongly it will be felt,” Oglesby says, noting a specific example from Alaska, where the waves of a quake were felt at a lake in Louisiana. The last time the San Andreas fault released a major earthquake was in 1857—it was a magnitude 8.0. This long period of time has some scientists worried about the next big one. “We’re in essence waiting for something big on the San Andreas to happen,” says Dr. Douglas Morton, adjunct professor of geology at UCR, who has a Ph.D. in geology and has been studying quakes in Southern California for about 40 years. “It’s a popular way to phrase it, that we’re overdue.” Morton also says that the Glen Helen Blockbuster Pavilion, home to such big events as the annual Ozzfest and the Renaissance Pleasure Faire, lies directly over a part of the fault.

“I’m worried about La Verne as much as any other place in Southern California. In terms of earthquake safety, there’s no place to go in Southern California that’s better. No matter where you go, there are faults,” Oglesby says. “I’m worried about all of the faults. People should build buildings with earthquakes in mind. You don’t want the building to fall apart from the ground shaking. Don’t just design buildings to withstand vertical force; build them to withstand horizontal forces as well, from side to side motion.”

La Verne resident Denise Monteith feels similarly. Monteith, who manages the downtown Claremont Starbucks, lives on Bonita Avenue. Although the four-year resident was initially surprised to find out there were three faults running below her community, she is not worried. “It doesn’t bother me. There are faults lines all over,” says Monteith, the wife and mother of two young children. “I figure the house was built in 1908; if it hasn’t gone down yet, it ain’t going down.”

So what does all this mean to the University of La Verne? According to Brian Worley, director of facilities management, the majority of buildings on campus are safe. Although recent buildings are built to code, Worley still has some concern. “The oldest buildings are the most dangerous for obvious reasons,” he says. “One of the biggest concerns I have is the clay tile roofs on Founders Hall and Miller Hall.” Worley says they are wired in place, but “they’re only as good as the age of the wire.” Worley also explored other possible scenarios with Founders Hall, the oldest building on campus. He brought an engineer to campus about five years ago to check the status of the building and to determine what it needed to be properly retrofitted. “The engineer’s biggest concern was the roof of Founders Hall—the roof could collapse,” Worley says, adding that ULV heeded the engineer’s recommendation that mechanical ties, a framework that attaches to the walls and roof, be put in place. “I think the sheer thickness of the walls will help the building,” he says. Miller Hall, meanwhile, was retrofitted in 1990, and Worley says it should be fine. Other prominent buildings on the campus, such as the three residence halls, are safe, Worley says. Although it was built almost 50 years ago, the Studebaker-Hanawalt dorm “would do well,” according to Worley, because it is composed of masonry brick. Brandt Hall is also as sturdy as a rock and ready for the shaking to begin. “Brandt was constructed in a time, 1962, where the standards were high,” Worley says. The last of the dorms, the Oaks buildings, were built in 1989. During construction, the buildings’ structure was strengthened to help lengthen their lives.

As for buildings in the city, Alex Ramirez, city of La Verne principal planner, says almost all the buildings are able to handle earthquakes. “The area where we’ve had concern is the downtown area. Some of the buildings still need retrofitting,” he says. Heroes Restaurant is in an area of some concern to Ramirez, as is the La Verne Florist, both on D Street. The newer buildings, like the Kohl’s department store on Foothill Boulevard, are all built to code, he says.

To protect themselves, some people find comfort in buying earthquake insurance. Some brokers offer insurance for as low as $480 a year, up to $1,500 a year. Depending on zip code and housing specifics, the insurance can cover up to $145,000 worth of quake damage. Steve Johnson, a La Verne Farmer’s Insurance agent, says that for a typical 1,700 square foot Third Street home, damage would be covered for up to $170,000 for an earthquake insurance premium of $528 a year. There would, however, also be a 15 percent deductible, where roughly the first $30,000 in damage would not be covered. “Insurance is based on replacement cost,” Johnson says, adding that everything from how many bathrooms a house has, to what kind of counter tops are in the kitchen helps determine the cost of insuring the house.

There are three types of faults: thrust, strike-slip and the normal fault. “The normal fault is not common in Southern California because it is caused by extension, not compression,” Oglesby says. “The plates are sliding past each other, but it’s not like it’s a chasm opening up.” In Southern California, the San Andreas is a classic strike-slip fault. It follows the coastline through northern and central California, then curves in a more southeastern direction when it reaches the San Gabriel Mountains, proceeding to hit the San Bernardino area, then passing through the Cajon Pass. According to Oglesby, the fault is slipping—while the Pacific side is moving north, the eastern side is slipping south. This fault is a problem for our region because it curves just north of Southern California, causing compression on the San Gabriel Mountains. As a result of this pressure, the mountains are slowly growing taller. As Oglesby notes, this strike-slip fault—where the two sides are moving in opposite, horizontal directions—is the fault to fear.

The San Gabriel Mountains did not always run east to west. In fact, it was the San Andreas fault that “spun around” the mountain range from more of a north-south direction. This happened over the course of millions of years, Oglesby says. In Northern and central California, the plates slide reasonably smoothly past each other. However, because the San Andreas fault curves before it hits this region in a move called the “Big Bend,” the sunny south is not so fortunate. This barrier to simple right-lateral motion creates immense stresses within the crust of Southern California.

In addition to the San Andreas fault, Southern California has more than 150 smaller faults that are also sliding and are capable of sizable damage. Other nearby faults capable of producing 6.0 earthquakes include the Chino fault, which runs underneath Chino and Corona; the Whittier fault, which runs underneath Yorba Linda and Hacienda Heights; and the Red Hill fault, also called the Etiwanda Avenue fault, which passes underneath Upland and Alta Loma. A strong earthquake from one of these faults would not be devastating to La Verne but would definitely be felt. “A 6.0 would give you a pretty good ride. You’d feel it,” Oglesby chuckles, adding that buildings would not crumble, but there would probably be destruction inside of homes from possessions knocked off shelves.

So, while it is possible that an earthquake could cause major devastation to La Verne and its surrounding communities, the experts offer some comfort. According to Morton, “La Verne, in essence, is in a much better position than other cities, like San Bernardino. Of course, as soon as I say that, something bad will happen.”