سؤال اليوم — اختبار STEP

Read the passage and answer the question. (1) Earthquakes are among the deadliest natural disasters, and for centuries people have hoped to predict them. Animals behaving strangely, changes in well water and unusual clouds have all been suggested as warning signs. Unfortunately, none of these has proved reliable. (2) Scientists today understand well why earthquakes happen. The Earth's outer layer is broken into huge plates that move slowly, a few centimeters a year. Where plates meet, stress builds up in the rocks over many years until they suddenly slip, releasing energy as seismic waves. Yet knowing why earthquakes occur is not the same as knowing exactly when they will occur. Seismologists can say which areas face the greatest risk and estimate the chance of a large earthquake over several decades, but they cannot name the day or the hour. (3) What has become possible is early warning. An earthquake produces two main kinds of waves. The first, called P-waves, travel faster but usually cause little damage. The slower S-waves that follow are the ones that shake buildings violently. Sensors that detect the P-waves can send an alert to people farther away before the stronger shaking arrives. Countries such as Japan and Mexico already operate such systems. (4) The warning may last only a few seconds, or perhaps a minute for places far from the center of the earthquake. That may not sound like much, but it can be enough to stop trains, close gas pipes and let people take cover under tables. (5) In the end, the most effective protection remains strong buildings. Cities that require earthquake-resistant construction suffer far fewer deaths than those with weak building rules, even when the shaking is just as strong. Question: It can be inferred from the passage that a town very close to the center of an earthquake