Catastrophic earthquake hits central Mexico

Ripple effect: Experts suggest that 30m people would have felt tremors from the quake. © Getty

Does earthquake prediction cause more harm than good? This is the question some experts are asking after over 200 people were killed in a 7.1 magnitude earthquake in the past 48 hours.

“The tragedy that devastated us yesterday has been one of the worst ever in the history of Mexico. There are hundreds of dead and wounded. We don’t have the exact or final numbers yet.”

These words were spoken by the then Mexican president, Miguel de la Madrid, the day after a colossal earthquake rocked Mexico City in 1985. But you could be forgiven for thinking that he was referring to the earthquake which struck central Mexico on Tuesday, 32 years to the day after the 1985 disaster.

Unlike in 1985, Tuesday’s earthquake was detected by Mexico’s sophisticated early warning system. Sirens blared in Mexico City 20 seconds before the first tremors were felt, giving people crucial moments to flee from inside vulnerable buildings.

This technology could save millions more lives in the future. Scientists from the United States Geological Survey (USGS) estimated in 2014 that there is a 72% likelihood of at least one earthquake of magnitude 6.7 or greater striking in the San Francisco Bay area before 2043. California’s early warning system is still under construction.

Still, these systems can only warn people of an earthquake seconds in advance, creating a sense of panic. “It’s a real possibility that we’d have more people die on the freeway trying to get away after a prediction than we’d have killed in an earthquake,” said Lucy Jones from the USGS.

It is impossible accurately to predict the exact time, location and magnitude of earthquakes. Even if an accurate prediction were possible, the University of Durham’s David Petley thinks that this would be more harmful than useful.

“It is likely that a large number of people would move away, businesses would shut down and the economy would probably go into freefall,” argues Petley.

How long would it take for things to return to normal? The social and economic cost of a correct prediction “might be greater than the cost of the earthquake itself”.

Quaking in their boots

Many feel that it is better to have some warning, however imprecise, than none at all. The early warning sign can make the difference between life and death. As for Petley’s opinion, it is inhumane to argue that it would be better to put people’s lives at risk for the sake of keeping towns and economies going. Those things can be rebuilt: lives cannot.

Others think that early warning systems come too late and that attempts at predictions are pointless. Even if you manage to escape from inside a building, 20 seconds is not long enough to reach safety. What’s more, earthquake predictions will mean that we live in fear of the next one. Much better to deal with the consequences of earthquakes as and when they happen.

You Decide

  1. What is worse: an earthquake or a hurricane?
  2. Mexico has had two earthquakes in one month. Why do people still live in areas which are so prone to natural disasters?

Activities

  1. Design a city built to withstand strong earthquakes. What features would it have to make sure its buildings and inhabitants survived?
  2. Research two natural disasters (they do not have to be earthquakes). Choose one example from a rich country and one from a poor country. How do their warnings, events and recoveries differ? Share your findings with the class.

Some People Say...

“We learn geology the morning after the earthquake.”

Ralph Waldo Emerson, American writer.

What do you think?

Q & A

What do we know?
Earthquakes are extremely hard to predict. There are some clues to suggest that an earthquake may be on its way, but none of them have proven reliable. Some scientists have tried to predict earthquakes using less conventional methods: many believe that animals can sense when an earthquake is coming. A colony of toads abandoned its pond in L’Aquila, Italy in 2009, just days before an earthquake.
What do we not know?
How many people have died in Tuesday’s earthquake. It is believed that many people are still trapped beneath rubble from collapsed buildings. The current figure is 225, but authorities anticipate that the final figure will be much higher.

Word Watch

Colossal earthquake
Mexico’s deadliest earthquake struck at 7:18am on September 19th 1985. The final death toll was never confirmed, with estimates ranging between 5,000 and 60,000. It was one of the strongest earthquakes ever to hit the area, measuring 8.1 on the Richter scale. According to the measure now used to assess the force of an earthquake the magnitude of that quake was 7.8.
Early warning system
An early warning system of 12 seismic sensors was installed in 1991, following the devastation of the 1985 quake. There are now 100 sensors along Mexico’s Pacific coast which detect any signs of movement in the earth’s crust and transmit them to a monitoring centre. Within minutes, alerts can be sent to social media, television stations and even to an app on people’s smartphones.
California
Earlier this year, President Trump tried to cut off funding to California’s early warning system building programme. However, he was blocked by a House of Representatives subcommittee, which voted to continue supplying the $10.2m dollars needed for construction to continue.

Subjects

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