Earthquakes are nothing new to residents in SoCal, but the recommended safety measures can be.
Like most of California, the Antelope Valley is susceptible to earthquakes. The San Andreas Fault Line, which runs through Palmdale and crosses the 14 Freeway near Avenue S, is approximately 800 miles long running northwest/southeast from Southern California to several hundred miles north of San Francisco. The San Andreas fault is capable of producing a large earthquake.
The San Andreas Fault is one active fault that borders the Antelope Valley, the other is the Garlock Fault.
“These faults form the ‘triangle’ visible on aerial photos of the valley. The proximity to active faults and their recurrence interval – an estimate of how often they produce earthquakes – are two factors that determine susceptibility to earthquakes in a given area,” said Geologist Irene Nester, a technical support contractor for the Environmental Restoration Program at Edwards AFB.
Nester said the San Andreas fault is located along the southwest edge of the Antelope Valley. The Garlock fault is less significant and is located along the northwest edge of the valley. There are also several faults in the northeastern portion of Edwards AFB, for example the Spring Fault, that may be inactive (not expected to produce earthquakes).
Nester added that the recurrence interval of the southern section of the San Andreas Fault, near the Antelope Valley, is “on the order of several hundred years.” And the Garlock fault’s recurrence interval for large earthquakes is longer; “estimated to be several hundred to several thousand years.”
According to Nester, the most recent large earthquakes near Edwards AFB occurred near Landers, Big Bear and Northridge, Calif. The Landers quake was approximately 90 miles southeast of the base at 4:57 a.m., June 28, 1992. It was followed at 8:05 a.m. by the 6.5 Big Bear quake. These two were followed by a much smaller earthquake near Mojave about two weeks later that may have been triggered by the Landers earthquake.
The Landers earthquake caused three deaths and more than 400 injuries.
“It occurred on several right-lateral strike-slip faults nearly simultaneously over a distance of approximately 50 miles in a lightly-inhabited area. The San Andreas is a right-lateral strike slip fault and is the main expression of the boundary between the Pacific and North American tectonic plates, which are moving slowly and continuously relative to each other. A strike slip fault moves primarily in a horizontal direction during an earthquake. The Garlock is a left-lateral strike-slip fault.”
The Jan. 17, 1994, Northridge quake also rattled Edwards AFB and the AV. The death toll from the quake was 57, with more than 5,000 injured, in Los Angeles and surrounding areas. In addition, earthquake-caused property damage in the L.A. area was estimated to be more than $20 billion, making it one of the costliest natural disasters in U.S. history.
The recent La Habra Earthquake March 28, which shook much of Los Angeles, and an aftershock in Rowland Heights the next day, are not-so-pleasant reminders for Antelope Valley residents to be adequately prepared.
“An earthquake can occur at any time and a large earthquake may cause interruptions in basic services and make travel difficult,” said Nester.
The Air Force’s www.beready.af.mil site encourages people to prepare for the next earthquake by recognizing and correcting earthquake hazards at home and work.
Air Force Be Ready suggests securing large furniture items that could topple during an earthquake, like bookshelves or water heaters that could be pulled away from pipes and rupture. Store loose heavy objects on lower shelves and hang picture frames and mirrors away from beds and couches. Add latches to cabinet doors to prevent objects from being thrown during an earthquake.
In addition to preparing your home, create a household emergency supply kit. The kit should have at least one or two portable containers filled with supplies to survive for at least three days without outside assistance. Smaller kits should be made for vehicles and offices.
“A three-day or more, per-person, supply of drinking water is particularly important in the desert environment,” said Nester.
If you are indoors when an earthquake hits, drop to the ground, take cover by getting under a sturdy piece of furniture and hold on until the shaking stops. Avoid glass and walls or objects that could fall. Only stand under a doorway if you are sure that it is load-bearing and nearby. If you are in bed at the time, stay there and use a pillow to protect your head.
According to www.ready.gov, “Research has shown that most injuries occur when people inside buildings attempt to move to a different location inside the building or try to leave.”
If you are outside when an earthquake hits, move away from buildings, street lights and utility wires. Persons in moving vehicles should also avoid stopping near buildings, trees and overpasses. If operating a vehicle, the driver should proceed with caution after an earthquake has stopped.
If in a Vehicle during an earthquake:
* Stop as quickly and safely as possible, and then remain in your vehicle
* Avoid stopping near or under buildings, trees, overpasses, and utility wires
* Proceed cautiously once the earthquake has stopped, watching for road and bridge damage
If Trapped Under Debris:
* Do not light a match or lighter
* Do not move about or kick up dust
* Cover your mouth with fabric or clothing
* Tap on a pipe or wall so rescuers can locate you or use a whistle if one is available
* Shout only as a last resort – shouting can cause you to inhale dangerous amounts of dust
Once an earthquake is over, check for injuries among your family and neighbors and seek medical help if necessary.
Fire is the most common hazard following an earthquake. People who have just experienced an earthquake are encouraged to use caution, and expect aftershocks which can cause further damage to structures. It is important once everyone has reached safety, to inspect your homes’ utilities for gas leaks, electrical system damage and sewer or water line damage.
Families are encouraged to make sure that all responsible parties in a household understand where the emergency supplies are located and what to do in the event of an earthquake. Regular earthquake drills at home prepare family members to respond safely when shaking is felt.
Read more about earthquakes and earthquake preparedness at http://www.beready.af.mil/disasters&emergencies/earthquake.asp.
For questions about what to do to prepare for, and what to do during and earthquake, visit Edwards AFB Emergency Management at Bldg. 2860 or call (661) 277-4433.
Additional information about earthquake safety, including an earthquake safety checklist, can be found at http://www.fema.gov/earthquake/earthquake-safety-home#1 and http://www.ready.gov/earthquakes.