Why do you need to drop to the ground during an earthquake?
During an earthquake, the ground beneath your feet will be shaking. Depending on the size and intensity of the earthquake, the ground could be shaking quite violently. Remaining standing in this situation could prove quite difficult. By dropping to the ground, you ensure that you are in control of your movement to the ground. If you remain standing, there is a chance that the earthquake shakes you off of your feet and you injure yourself in the resulting fall. Hitting your head on something on the way down is also a strong possibility. Ready.gov has a slightly humorous way of explaining why you should drop to the ground.
Drop down onto your hands and knees so the earthquake doesn’t knock you down. Drop to the ground (before the earthquake drops you!)
Dropping to the ground is a good start for protecting yourself against potential earthquake threats, but your situation can be improved after dropping to the ground. If it is possible, you should attempt to crawl under sturdy furniture of some kind and hold onto the furniture. Dining room tables and desks are both good options. They will protect you from objects that could fall on you and cause further injury. If crawling under something is not an option, you should cover your head and neck with your arms to protect yourself from falling debris. In addition to seeking cover under sturdy pieces of furniture, you should seek to distance yourself from both windows and exterior walls.
By dropping down low to the ground during an earthquake, you are less likely to lose balance and fall due to the seismic activity. As soon as you feel an earthquake's waves, get down on all fours and seek shelter under a sturdy table or desk. If no furniture is conveniently available, huddle against an interior wall. If you try to stand up and walk around during an earthquake—even to try and get to safety—you risk falling over and sustaining an injury on impact.
Being low to the ground and seeking shelter under strong furniture or against a wall offers you protection from objects falling from the walls or ceiling.
If you use a wheelchair or other mobility device and cannot quickly or safely get out of it, lock your tire brakes and lean over, protecting the back of your neck with your hands. Try to park your wheelchair against an interior wall if possible. If you don't use a mobility device and can easily seek shelter under furniture, you should also protect the back of your neck and head with your hands.