A University of Missouri expert says the huge earthquake that devastated northeast Japan last week is entirely different than the earthquakes that took place along Missouri’s New Madrid fault.
Mian Liu, professor of geological sciences in the College of Arts and Science, has studied earthquakes in many places, including the New Madrid fault in southeastern Missouri. He said the historic earthquake that struck Japan, which had a seismic magnitude of 9.0, was caused by shifting between tectonic plates.
Earthquakes in the New Madrid fault region, on the other hand, occur on a complicated network of interacting faults within the North American plate. A large earthquake on one fault can increase the stress on other faults, making some of them more likely to have a major earthquake. The major faults may stay dormant for thousands of years and then wake up to have a short period of activity.
In a recent study published in the journal Lithosphere, Liu and co-authors Seth Stein, a professor of earth and planetary sciences at Northwestern University, and Hui Wang, a Chinese Earthquake Administration researcher, said that high-precision Global Positioning System (GPS) measurements in the past two decades have found no significant strain in the New Madrid area, which had three to four large earthquake events during 1811-12, and perhaps a few more in the past thousand years.
“As far as the New Madrid fault is concerned, we need to look at the ‘big picture’ of interacting faults, rather than focusing only on the faults where large earthquakes occurred in the recent past,” Liu said. “Earthquake histories in countries like China, where excellent historic records were kept, indicate that large earthquakes in mid-continent tend to migrate among faults.”
However, Liu said, even with advances in science and technology, it’s still impossible for scientists to predict where and when the next earthquake will strike. Liu said that Japan is a world leader in earthquake research, due to the frequency of earthquakes that occur there and Japan’s advanced monitoring networks. He noted that Japan’s earthquake hazard map indicates the most danger to be along the coast of southern Japan. The recent earthquake — the largest in Japan’s recorded history and one of the most powerful ever recorded — ruptured along Japan’s northern shore.
“This just shows how much uncertainty goes into our assessment of earthquake hazard, because in Japan we have the best information available to earthquake science, yet it was still missed,” said Liu.
Officials fear the death toll from the Japan quake could exceed 10,000 people. A giant tsunami slammed into Japan’s coast, washing away homes, cars and boats. Thousands of people are still missing. At least two nuclear reactors were damaged following a series of explosions.