BTectonic plates in Earth's crust suddenly shifting after stress builds up along their edges
CUnderground explosions from volcanoes
DHeavy rain making the ground unstable
Earth's outer layer is made of huge plates of rock that are slowly moving. Where these plates meet, they push, pull, or slide against each other. Friction holds them in place temporarily, but stress builds up. When the stress becomes too great, the plates suddenly slip, releasing energy as waves that shake the ground. Most earthquakes happen at plate boundaries where this stress accumulates.
Question 2 True / False
During an earthquake, the ground opens up into huge holes that can swallow buildings.
TTrue
FFalse
Answer: False
This is a common myth from movies. During most earthquakes, the ground shakes but does not open into large chasms. The danger from earthquakes comes from the shaking itself -- it can collapse buildings, break roads and bridges, and cause landslides. Earthquake safety is about protecting yourself from falling objects and building damage, not from falling into the earth.
Question 3 Short Answer
What should you do if an earthquake starts while you are indoors?
Think about your answer, then reveal below.
Model answer: You should Drop, Cover, and Hold On. Drop to the ground so you do not fall. Take Cover under a sturdy piece of furniture like a desk or table to protect yourself from falling objects. Hold On to the furniture and stay there until the shaking stops. Stay away from windows and heavy objects that could fall.
Earthquake safety is one of the most practical outcomes of learning about earthquakes. The Drop-Cover-Hold On method is recommended by emergency management agencies worldwide and is effective because most earthquake injuries come from falling objects, not from the ground itself.