A magnitude 6.9 earthquake struck the Indonesian island of Lombok and the adjacent Gili Islands this week, and was felt on the nearby tourist island of Bali. Leaving more than 300 dead and around 84,000 others displaced, the event is yet another chapter in the age-old seismic story of humans trying to cope with an unpredictably rattling planet. But even though quakes have always been with us, something about them tends to leave us stunned and caught off guard. A lot of people start running for the exits the moment the shaking starts.
Many recommended earthquake preparedness strategies have multiple steps, and experts’ guides to best practices get tweaked and refined over the years as experience accumulates, scientific knowledge expands and construction techniques evolve. Situational awareness and having a plan (pdf) in mind remain key. But if a quake strikes when one is inside a building, many experts’ core mantra remains surprisingly simple and unchanging: Drop, cover and hold on.
This method is promoted by the U.S. Department of Homeland Security, American Red Cross (pdf), Federal Emergency Management Agency, the U.S. Geological Survey (USGS), the New Zealand Ministry of Civil Defense and Emergency Management (pdf) and the Japanese government, to name but a few. None of these recommend going outside if one is already in a building.
As soon as you feel any shaking, the guidelines advise, do not wait to see if it gets stronger. Drop to your hands and knees, cover your head, locate a sturdy table or desk and crawl under it. Then hold onto one of its legs and do not come out until at least a minute after the shaking stops. No sturdy desk? Stay on your knees in the corner of a room. If you are in bed, lie face down and cover your head (pdf) with a pillow. Stay away from windows and unfixed objects.
As for standing in a doorway, the USGS and some other agencies say this is outdated advice—based largely on old photographs of doorframes still standing in otherwise collapsed unreinforced masonry or adobe buildings. Today doorframes are often no stronger than the rest of a house and do not offer much protection from falling debris.
Make sure you stay put until the shaking has clearly stopped. It is not easy to know what part of an earthquake cycle one is experiencing; it could be a foreshock to something larger or perhaps a strong aftershock is on its way. An end to lighter, initial shaking can give people an erroneous sense of control and safety, and the subsequent violence can take them by surprise. “That’s why, when we recommend drop, cover and hold on, we say, ‘Drop before the earthquake drops you,’” says Jason Ballmann, communications manager for the Southern California Earthquake Center.
The idea of staying inside a swaying building can seem counterintuitive, to say the least. The horrific images of collapsed buildings that emerge after major quakes understandably imprint themselves onto the public consciousness. This may make it seem like running for the exit is a good idea—but such photographs can sometimes give a false impression of the primary hazards associated with earthquakes.
Ballmann says rescue teams retrieving people from collapsed structures around the world can attest to the effectiveness of the drop, cover and hold on strategy. Thanks to increasingly strict building codes in a rising (pdf) number of countries, modern buildings are becoming less likely to collapse. A greater danger often comes from falling and flying objects—which is precisely why getting under a table is a highly recommended course of action.
Ken Hudnut, a California Institute of Technology geophysicist who has studied earthquakes worldwide with the USGS, points out there can be an interesting caveat to drop, cover and hold on. A few cities including San Francisco and Los Angeles have required seismic retrofits for older building types, meaning one is generally safer inside them, Hudnut says. However, a broader lack of such ordinances—along with uneven enforcement of building codes all over the world, including within the U.S.—do make it harder know if a structure will withstand a major quake. This can endanger those outside a building as well. “If you are in an older structure and you do try to run outside, you are putting yourself at risk of the building falling on you,” Hudnut says. “That’s a really bad idea.”
Caltech seismologist Lucy Jones, author of The Big Ones: How Natural Disasters Have Shaped Us and scientist emerita at the USGS, says “collapsing buildings are rare—extremely so in places like Chile, California or Japan”—and even in places with the worst construction. “In the rare situation that your building does collapse, drop, cover and hold on can be the best choice. It likely gives you some defensible air space to wait for rescue.”
Jones notes one relatively improbable situation in which it may be advisable to make a run for it: if a person is at the entrance of a poorly built structure, far from any tables, and can get to a clear outside space and away from the building extremely quickly. Still, she adds experts endorse drop, cover and hold on because it is “the best answer for most situations.” Hudnut says this “universal advice” has “a really great basic sensibility to it.”
Nearly half the U.S. population is exposed to potential damaging earthquakes, which is why drills are held regularly in some regions. A wide range of groups—including national, state and local governments—hold such dry runs during Great ShakeOut Earthquake Drills, a global initiative Ballmann helps coordinate.
International ShakeOut Day is held annually on the third Thursday of October. Countries from Japan to New Zealand take part, hoping repetitive practice will simply become instinct. Many earthquake-riddled nations, however, remain conspicuously absent from the list of participants.
The recent deaths in Indonesia are likely attributable to a range of complex, interrelated factors, including poor building quality (pdf). But it is clear that the more people practice proper safety measures—no matter where they are—the more likely they will be to survive a major quake.