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.”