Understanding mysterious continental intraplate earthquakes

Oct 12, 2007

A new volume published by the Geological Society of America sheds light on mysterious earthquakes in the interiors of continents. These earthquakes, like those that occur in the central U.S., are what the book's editors describe as "an embarrassing stepchild of modern earthquake seismology." Continental Intraplate Earthquakes: Science, Hazard, and Policy Issues provides a comprehensive overview of these rare but very real global hazards.

The plate tectonics revolution of the 20th century elegantly explained why most earthquakes occur where they do – at Earth's plate boundaries. It didn't explain, however, the occurrence of intraplate quakes and the deformation processes that give rise to them. As a result, geologists studying areas like the central U.S., western Europe, and Australia, don't know what causes these quakes, how often they will happen in the future, and how dangerous they are.

"Progress has been slow and somewhat difficult," said volume editor Seth Stein of Northwestern University, Evanston, Illinois, USA. "Because deformation within plates is slow compared to more rapid plate boundary motions, seismicity is much lower and harder to study."

Stein points out that in recent years important insights are emerging with use of new research techniques and approaches. Space geodesy can measure intraplate deformation. Paleoseismology can extend the somewhat sketchy instrumental record backwards in time. Numerical deformation modeling can be used to test hypotheses regarding stresses.

The emerging picture shows earthquakes moving around among faults, which are active for some time and then become inactive for a long time. The results can be used to develop strategies for mitigating earthquake damage while balancing the resources required with those needed for other societal goals.

In organizing the publication Stein and co-editor Stéphane Mazzotti of the Geological Survey of Canada drew on presentations from a number of meetings and other sources that integrated what has been learned from earthquakes around the world. "Because these earthquakes are relatively rare in any given area, combining data from many areas provides valuable insights," said Stein.

One group of papers addresses where intraplate quakes occur and what causes them. A second group assesses the hazards posed and challenges in estimating probability, size, and shaking. A third group explores public policy issues surrounding cost-effective hazard mitigation.

Source: Geological Society of America

Explore further: How productive are the ore factories in the deep sea?

add to favorites email to friend print save as pdf

Related Stories

Recommended for you

How productive are the ore factories in the deep sea?

14 hours ago

About ten years after the first moon landing, scientists on earth made a discovery that proved that our home planet still holds a lot of surprises in store for us. Looking through the portholes of the submersible ...

NASA image: Volcanoes in Guatemala

19 hours ago

This photo of volcanoes in Guatemala was taken from NASA's C-20A aircraft during a four-week Earth science radar imaging mission deployment over Central and South America. The conical volcano in the center ...

User comments : 0

More news stories

Untangling Brazil's controversial new forest code

Approved in 2012, Brazil's new Forest Code has few admirers. Agricultural interests argue that it threatens the livelihoods of farmers. Environmentalists counter that it imperils millions of hectares of forest, ...

Study links California drought to global warming

While researchers have sometimes connected weather extremes to man-made global warming, usually it is not done in real time. Now a study is asserting a link between climate change and both the intensifying California drought ...

Genetic code of the deadly tsetse fly unraveled

Mining the genome of the disease-transmitting tsetse fly, researchers have revealed the genetic adaptions that allow it to have such unique biology and transmit disease to both humans and animals.