Magnitude seven times two

Disaster Prevention and Management

ISSN: 0965-3562

Article publication date: 31 August 2010



Ritchie, L. (2010), "Magnitude seven times two", Disaster Prevention and Management, Vol. 19 No. 4.



Emerald Group Publishing Limited

Copyright © 2010, Emerald Group Publishing Limited

Magnitude seven times two

Article Type: News items From: Disaster Prevention and Management, Volume 19, Issue 4

The January 12, 2010 Haitian earthquake was more than twice as deadly as any previous magnitude 7.0 event, according to University of Colorado seismologist Roger Bilham.

Writing in the journal Nature ( Bilham says that the reason for this enhanced damage is obvious:

The buildings had been doomed during their construction. Every possible mistake was evident: brittle steel, coarse non-angular aggregate, weak cement mixed with dirty or salty sand, and the widespread termination of steel reinforcement rods at the joints between columns and floors of buildings where earthquake stresses are highest.

There have been a rash of earthquakes around the globe in recent weeks, some as strong as Haiti’s, but none as deadly. A 7.2 magnitude quake centered near Mexicali, Mexico killed two people and injured 233 (

The Mexicali quake’s epicenter was only six miles deep – quite shallow as these things go – and it opened fissures in the ground. The Mexicali event was felt as far away as Los Angeles, and sparked calls for better preparation for Southern California to try to avert catastrophe. But emergency officials say that the state’s budget crisis has already strained resources. “We know that there’s going to be an earthquake, and we know it’s going to be a major natural disaster,” Lou Paulson, President of the California Professional Firefighters and a captain in the Contra Costa County fire protection district told the Los Angeles Times. “And I don’t want to be one of the people who stands in front of the state of California and says, ‘We told you so’.”

A Mw 7.7 quake hit northern Sumatra on April 7, but no loss of life was reported. A tsunami warning was initially issued, but then canceled when a hazardous wave failed to develop. People in some communities – still mindful of the catastrophic 2004 Indian Ocean tsunami – reportedly ran into the streets and immediately sought higher ground (

An estimated 230,000 people were killed in Haiti. CU’s Bilham added:

The death and injury of about 15 percent of more than 2.5 million people in Port-au-Prince and its urban agglomeration, and the roughly 1.5 million people now homeless, is a consequence of many decades of unsupervised construction permitted by a government oblivious to its plate boundary location.

Bilham wrote:

In recent earthquakes, buildings have acted as weapons of mass destruction. It is time to formulate plans for a new United Nations mission – teams of inspectors to ensure that people do not construct buildings designed to kill their occupants.

The February 27, 2010 earthquake that struck Chile was powerful enough to move the city of Concepcion at least ten feet to the west, as well as shift the earth’s axis enough to make each day 1.26 microseconds shorter, according to measurements by several university teams and the National Aeronautics and Space Administration ( But it was not as damaging as the less powerful Haitian quake, because of what the insurance company Swiss Re called “the highly advanced anti-seismic construction standards in Chile.”

The company provided preliminary estimates in early March of insured losses from the Chile quake, ranging from $4 billion to $7 billion. The company said:

In Chile, it is common practice for owners of mortgaged residential property, commercial and industrial property to buy earthquake insurance from local and global private insurance companies. Accordingly, this latest earthquake will lead to significant insurance claims for property damage and business interruption which are designed to facilitate a swift economic recovery (

In general, earthquakes are taking a higher toll of life worldwide. Over the past ten years, nearly 60 percent of the people killed in disasters have died in earthquakes, according to the Center for Research on Epidemiology of Disasters (CRED) (

According to the figures released by CRED at the end of January, 3,852 disasters have killed more than 780,000 people over the past ten years. Asian disasters account for 85 percent of all fatalities.

“After earthquakes, storms (22 percent) and extreme temperatures (11 percent) were the most deadly disasters between 2000 and 2009,” CRED reported. The other most deadly disasters of the decade of the 2000s were the 2004 Indian Ocean Tsunami, which left 226,408 dead in several Asian nations. Cyclone Nargis killed 138,366 people in Myanmar in 2008. The 2008 Sichuan earthquake in China killed 87,476. In his Nature paper, CU’s Bilham said:

Since the turn of the century, earthquakes have directly or indirectly (including tsunami) claimed the lives of more than 640,000 people, four times more than in the preceding two decades, and proportionately more than the global increase in population would anticipate. If buildings are not made earthquake resistant, the toll is likely to continue to rise as cities grow in population (extracted from Natural Hazards Observer, May 2010).

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