"They should also expect aftershocks." What are aftershocks?

When the ground begins to shake, the safest thing is not to run. People who are indoors are advised to stay inside, to keep away from doorways, and to protect themselves at once with three simple actions: Drop, Cover and Hold On.

Drop down onto your hands and knees, so that the shaking cannot knock you over. Cover your head and neck with one arm and hand, and if there is a sturdy table nearby, crawl underneath it. Then hold on until the shaking stops.

The advice changes a little with the situation. If you are in bed, turn face down and cover your head and neck with a pillow. If you are driving, pull over, stop and put on the parking brake. If you are outdoors, move to an open area away from buildings, trees, streetlights and power lines, all of which can fall.

Preparing in advance helps too. Heavy things such as bookcases and refrigerators can be fixed firmly in place, and breakable objects kept on low shelves. A family can practise what to do and keep supplies of food, water, a torch and a whistle. After the shaking stops, people should leave a damaged building and not go back in. They should also expect aftershocks, the smaller earthquakes that often follow the main one, and be ready to drop, cover and hold on again.