News / Science & Technology

Earthquake Science Still a Shaky Business

Accurate predictions still elude scientists

New Madrid Earthquakes 1811-12. One side of fault trench or "fissure" near banks of St. Francis River, Clay County, Arkansas. 1904.
New Madrid Earthquakes 1811-12. One side of fault trench or "fissure" near banks of St. Francis River, Clay County, Arkansas. 1904.



The magnitude 5.8 earthquake that rattled the East Coast of the United States in August caught everyone - even geologists - by surprise. But even when there's reason to think an earthquake could be around the corner, scientists still can't make good predictions.

It’s been 200 years since big earthquakes rocked the New Madrid Seismic Zone, a fault system that runs down the central U.S. through parts of Illinois, Missouri, Kentucky, Arkansas and Tennessee. The region has had plenty of smaller quakes since then, but no one can really say when the next big one might be.

The New Madrid earthquakes of the winter of 1811 to 1812 have become the stuff of legend. They were so powerful, the story goes, they made the Mississippi River run backwards.

“It was what we call a thrust fault," says Susan Hough of the U.S. Geological Survey in Pasadena, California. "And it came up to the surface beneath the river and actually created a stair step in the river bottom, to where it set up waves that went coursing back upstream.”

According to Hough, much of what we know about those early quakes comes from first-hand accounts, like this one written by future United States president Zachary Taylor, who felt the shaking 370 kilometers away in Louisville, Kentucky.

The sight was truly awful: houses cracking; chimneys falling; men, women and children running in every direction - in their shirts - for safety and a friend of mine was so much alarmed as to jump (out) of a window and was very much hurt.

Hough’s calculations put the largest New Madrid earthquake at about 7.0, the same magnitude as the January 2010 earthquake in Haiti. The official USGS estimate is 7.7.

The problem is, scientists can’t predict when, where, or even if another earthquake will happen.

Northwestern University geophysicist Seth Stein doesn’t expect another big quake at New Madrid anytime soon. He and others have been using GPS technology to measure how the ground moves - or deforms - along active faults.

“Now, normally the way earthquakes work is that you store up energy, the ground deforms before a big earthquake - kind of like stretching a spring - and then it snaps, and you have an earthquake,” Stein says.

That warping of the ground has been measured in California, Alaska, Oregon, and Washington - along every U.S. fault where we think a big earthquake is on the way. So that’s what Stein and his colleagues expected to see when they started taking those same kinds of GPS measurements at New Madrid.

To their complete surprise, they saw absolutely no motion of the ground. Stein says part of the explanation could be that seismic zones in the middle of a continent seem to behave differently from those in places like California, where the huge plates that make up the earth’s surface thrust up against each other.

“Faults in the middle of the continents will be active for short periods of time geologically, maybe a few thousand years, and then they’ll turn off and be inactive for times, and then start up again," he says. "So it looks like we may be seeing the end of one of those cycles.”

But many other geologists don’t agree. Robert Williams of the USGS in Colorado says you can’t ignore the past. The earthquakes 200 years ago liquefied the soil underground, blasting jets of wet sand out onto the surface.

“There’s been some great science done, with geologists digging into these 1811, 1812 sand blows, and then, lo and behold, discovering evidence for older sand blows caused by earthquakes of about the same magnitude as the 1811, 1812 sequence,” Williams says.

They realized that before 1811, there had been quakes in about 1450, and again before that, in 900. Williams says that pattern of very large earthquakes means another big one could be on the way.

“We can’t predict earthquakes. So the geologic record is really the strongest piece of evidence we have to remain concerned about earthquakes there in the New Madrid region.”

Experts hope by the time the next big quake does hit the region, we’ll be ready for it.

You May Like

Video Americans, Tourists, Reflect on Meaning of Thanksgiving

VOA garnered opinions from several people soon after November 13 Paris attacks, which colored many of their thoughts

Video Thais Send Security Concerns Down the River

In northern Thailand, the annual tradition of constructing floating baskets to carry away the year’s bad spirits highlights the Loy Krathong festival

Video Tree Houses - A Branch of American Dream

Workshops aimed at teaching people how to build tree houses have become widely popular in America in recent years

This forum has been closed.
There are no comments in this forum. Be first and add one

Featured Videos

Your JavaScript is turned off or you have an old version of Adobe's Flash Player. Get the latest Flash player.
Belgium-Germany Border Remains Porous, Even As Manhunt For Paris Attacker Continuesi
Ayesha Tanzeem
November 25, 2015 10:46 PM
One of the suspected gunmen in the Nov. 13 Paris attacks, Salah Abdeslam, evaded law enforcement, made his way to Belgium, and is now believed to have fled to Germany. VOA correspondent Ayesha Tanzeem makes the journey across the border from Belgium into Germany to see how porous the borders really are.

Video Belgium-Germany Border Remains Porous, Even As Manhunt For Paris Attacker Continues

One of the suspected gunmen in the Nov. 13 Paris attacks, Salah Abdeslam, evaded law enforcement, made his way to Belgium, and is now believed to have fled to Germany. VOA correspondent Ayesha Tanzeem makes the journey across the border from Belgium into Germany to see how porous the borders really are.

Video Islamic State Unfazed by Losses in Iraq, Syria

Progress in the U.S.-led effort to beat Islamic State on its home turf in Iraq and Syria has led some to speculate the terror group may be growing desperate. But counterterror officials say that is not the case, and warn the recent spate of terror attacks is merely part of the group’s evolution. VOA National Security correspondent Jeff Seldin has more.

Video Taiwan Looks for Role in South China Sea Dispute

The Taiwanese government is one of several that claims territory in the hotly contested South China Sea, but Taipei has long been sidelined in the dispute, overshadowed by China. Now, as the Philippines challenges Beijing’s claims in an international court at The Hague, Taipei is looking to publicly assert its claims. VOA’s Bill Ide has more from Beijing.

Video Syrian Refugees in US Express Concern for Those Left Behind

Syrian immigrants in the United States are concerned about the negative tide of public opinion and the politicians who want to block a U.S. plan to accept 10,000 Syrian refugees. Zlatica Hoke reports many Americans are fighting to dispel suspicions linking refugees to terrorists.

Video After Paris Attacks, France Steps Up Fight Against IS

The November 13 Paris attacks have drawn increased attention to Syria, where many of the suspected perpetrators are said to have received training. French President Francois Hollande is working to build a broad international coalition to defeat Islamic State in Syria and in Iraq. Zlatica Hoke reports.

Video US, Cambodian Navies Pair Up in Gulf of Thailand

The U.S. Navy has deployed one of its newest and most advanced ships to Cambodia to conduct joint training drills in the Gulf of Thailand. Riding hull-to-hull with Cambodian ships, the seamen of the USS Fort Worth are executing joint-training drills that will help build relations in Southeast Asia. David Boyle reports for VOA from Preah Sihanouk province.

Video Americans Sharpen Focus on Terrorism

Washington will be quieter than usual this week due to the Thanksgiving holiday, even as Americans across the nation register heightened concerns over possible terrorist threats. VOA’s Michael Bowman reports new polling data from ABC News and the Washington Post newspaper show an electorate increasingly focused on security issues after the deadly Islamic State attacks in Paris.

Video World Leaders Head to Paris for Climate Deal

Heads of state from nearly 80 countries are heading to Paris (November 30-December 11) to craft a global climate change agreement. The new accord will replace the Kyoto Protocol on Climate Change that expired in 2012.

Video Uncertain Future for Syrian Refugee Resettlement in Illinois

For the trickle of Syrian refugees finding new homes in the Midwest city of Chicago, the call to end resettlement in many U.S. states is adding another dimension to their long journey fleeing war. Organizations working to help them integrate say the backlash since the Paris attacks is both harming and helping their efforts to provide refugees sanctuary. VOA's Kane Farabaugh reports.

Video Creating Physical Virtual Reality With Tiny Drones

As many computer gamers know, virtual reality is a three-dimensional picture, projected inside special googles. It can fool your brain into thinking the computer world is the real world. But If you try to touch it, it’s not there. Now Canadian researchers say it may be possible to create a physical virtual reality using tiny drones. VOA’s George Putic reports.

Video New American Indian Village Takes Visitors Back in Time

There is precious little opportunity to experience what life was like in the United States before its colonization by European settlers. Now, an American Indian village built in a park outside Washington is taking visitors back in time to experience the way of life of America's indigenous people. Carol Pearson narrates this report from VOA's June Soh.

Video Even With Hometown Liberated, Yazidi Refugees Fear Return

While the northern Iraqi town of Sinjar has been liberated from Islamic State forces, it's not clear whether Yazidi residents who fled the militants will now return home. VOA’s Mahmut Bozarslan talked with Yazidis, a religious and ethnic minority, at a Turkish refugee camp in Diyarbakır. Robert Raffaele narrates his report.

Video Nairobi Tailors Make Pope Francis’ Vestments

To ensure the pope is properly attired during his visit, the Kenya Conference of Catholic Bishops asked the Dolly Craft Sewing Project in the Nairobi slum of Kangemi to make the pope's vestments, the garments he will wear during the various ceremonies. Jill Craig reports.

Video Cross-Border Terrorism Puts Europe’s Passport-Free Travel in Doubt

The fallout from the Islamic State terror attacks in Paris has put the future of Europe’s passport-free travel area, known as the "Schengen Zone," in doubt. Several of the perpetrators were known to intelligence agencies, but were not intercepted. Henry Ridgwell reports from London European ministers are to hold an emergency meeting Friday in Brussels to look at ways of improving security.

Video El Niño Brings Unexpected Fish From Mexico to California

Fish in an unexpected spectrum of sizes, shapes and colors are moving north, through El Niño's warm currents from Mexican waters to the Pacific Ocean off California’s coast. El Nino is the periodic warming of the eastern and central Pacific Ocean. As Faiza Elmasry tells us, this phenomenon thrills scientists and gives anglers the chance of a once-in-a-lifetime big catch. Faith Lapidus narrates.

Video Terrorism in Many Forms Continues to Plague Africa

While the world's attention is on Paris in the wake of Friday night's deadly attacks, terrorism from various sides remains a looming threat in many African countries. Nigerian cities have been targeted this week by attacks many believe were staged by the violent Islamist group Boko Haram. In addition, residents in many regions are forced to flee their homes as they are terrorized by armed militias. Zlatica Hoke reports.

Video Study: Underage Marriage Rate Higher for Females in Pakistan

While attitudes about the societal role of females in Pakistan are evolving, research by child advocacy group Plan International suggests that underage marriage of girls remains a particularly big issue in the country. VOA’s Ayesha Tanzeem reports how such marriages leads to further social problems.

VOA Blogs