NSF Awards $2.16 Million for Intraplate Earthquake Studies

Among the many mysteries of our planet’s geology is why earthquakes occur in the middle of presumably stable tectonic plates. A project led by a group of University of Missouri-Columbia researchers has been awarded $2.16 million from the National Science Foundation (NSF) to bolster the collaborative efforts between the U.S. and China in determining the cause of intraplate earthquakes that have occurred in both countries.

Mian Liu, professor of geophysics in the College of Arts and Science, leads this multi-institutional study with a team of colleagues from MU’s Department of Geological Sciences. Those colleagues are: Associate Professor Eric Sandvol and Assistant Professors Francisco (Paco) Gomez and Milene Cormier. The MU team will work with its U.S. and Chinese partners to explore the fundamental physics that control intraplate earthquakes. Knowledge gained from North China will help in understanding earthquakes in the New Madrid area and other seismic zones in central and eastern U.S., as well as benefit the broader geosciences community through the production of data sets, computer models and curriculum materials.

“This is not a research project in the traditional sense,” Liu said. “Through the collaborative research, we want to provide our students with a unique international experience.”

Unlike interplate earthquakes in California and many other places where the earth’s crust is stressed by the relative motion of tectonic plates, which are pieces of the Earth’s rigid outer shell, intraplate quakes happen in the middle of presumably stable tectonic plates and thus cannot be readily explained. In the past seven centuries, more than 50 large earthquakes have struck North China. On July 28, 1976, a magnitude 7.6 earthquake killed 244,000 people and nearly wiped out the industrial city of Tangshan, about 200 miles southeast of Beijing. Intraplate earthquakes in the U.S. have not been as frequent but have been severe. In 1811 and 1812, a series of large earthquakes with estimated magnitudes above 7.0 occurred on the New Madrid faults in southeastern Missouri within the span of three months. The region remains seismically active today.

Liu and the MU team have been working with Chinese colleagues in a pilot study of North China earthquakes in recent years. This PIRE (Partnerships for International Research and Education) project will build a broad partnership to investigate what causes large intraplate quakes in North China and improve understanding of intraplate seismic activity in central and eastern United States. The U.S. partners include the University of Oklahoma, University of Colorado, North Carolina State University, U.S. Geological Survey, the Incorporated Research Institutions for Seismology (IRIS), and UNAVCO. The Chinese partners include two top Chinese universities, the Chinese Academy of Sciences and the China Earthquake Administration.

“PIRE is a new NSF program intended to strengthen collaboration between U.S. and international institutions,” Liu said. “The long-term goal is to educate and train a new generation of globally engaged American scientists and engineers.”

About 15 graduate students, 20 undergraduate students and 50 science teachers from the Midwestern states around the New Madrid seismic region will participate in this project. Lloyd Barrow, professor of science education in MU’s College of Education, will assist the educational and outreach activity.

Underrepresented minority students will be recruited, and most student participants will travel to China to work with Chinese students and scientists. Liu said that this is a great time to collaborate with China on earthquake studies. In recent years, China has infused large amounts of equipment and funds into earthquake research that has caught the attention of the international geosciences community. This year, the National Science Foundation of China launched an ambitious research initiative with $20 million to study earth structure and earthquakes in North China. For this PIRE project, the Chinese partners will provide most of the field equipment, logistical support, and complementary expertise.

“MU has shown a very strong institutional support and commitment to this project,” Liu said. “We’ve received a lot of support and a lot of resources from the University community, and we hope to bring long-term benefit of international collaboration to our campus and community through this partnership. We want to better understand this type of earthquakes, because it’s particularly important to the state of Missouri.”

Studying Evidence From Ice Age Lakes

Northern Dvina starts as the confluence of Yug River (on left) and Sukhona River (on top) near Velikiy Ustyug
Northern Dvina starts as the confluence of Yug River (on left) and Sukhona River (on top) near Velikiy Ustyug

During the last Ice Age, the ice dammed enormous lakes in Russia. The drainage system was reversed several times and the rivers flowed southwards. A group of geologists is now investigating what took place when the ice melted and the lakes released huge volumes of fresh water into the Arctic Ocean.

“The ice-dammed lakes in Russia were larger than the largest lakes we know today,” Eiliv Larsen, a geologist at the Geological Survey of Norway (NGU), tells me. He is in charge of the important SciencePub International Polar Year project that is studying natural climate changes in the Arctic and the ways in which man has adapted to them.

Moving glaciers

“The entire drainage system in Russia has been reversed several times during the past 130 000 years. The heavy ice cap covering the land area in the north dammed up lakes and forced the large rivers, the Dvina, Mezen, Pechora and Vychegda, to flow southwards to the Caspian Sea, the Black Sea and on to the Mediterranean,” Eiliv Larsen continues.

However, the ice margin in the north shifted; the ice cap varied in extent, sometimes suddenly advancing eastwards, sometimes retreating. When the plug was released as the ice melted, the water poured from the huge lakes into the Kara Sea and the White Sea, causing the sea level to rise.

The sum total of all these dramatic changes greatly influenced the climate and the circulation in the seas in the Barents Region. SciencePub scientists are trying to find answers to where, when and how often this took place.

Digging down

“We drive vehicles and boats along the large valleys and rivers,” Maria Jensen, a group leader and geologist at NGU, tells me. “Where sediments are exposed along the coast and rivers, we study the sequence of their deposition. It’s here, in the transportation of clay, silt and sand out into the marine system, that we find evidence of the major events,” she points out.

In a cutting beside the River Vychegda, a few kilometres from the village of Ust Nem in the Komi Republic, geologists from Norway, Denmark, Russia and Germany are digging their way down through layers that were deposited during the last Ice Age.

Astrid Lyså, another NGU geologist, explains: “We remove the outermost layer to get at undisturbed sediments. Then we clean the section, measure it, and photograph, draw and describe the structures in every single layer. We also take samples to date the beds using luminescence, a technique that reveals, for example, when a sand grain was last exposed to the light.”

Reading the history

By investigating a given section, geologists can, for instance, find out what types of deposits are present in the area. They may be moraine, peat, mire, or sediments deposited in the sea, rivers and ice-dammed lakes. The scientists can also find out in which environment these sediments were deposited; was it deep, still or shallow water, beneath the ice, or were the sediments deposited by the wind?

It is thus actually possible to read the history of an ice-dammed lake by studying the succession of layers dug out with a spade, a scraper, a knife and a trowel.

That is precisely what they are doing here at Ust Nem. There seems to have been two ice-dammed lakes here. The patterns of patches of coloured clay and the remains of crushed clay in the sediments suggest, for example, a strong increase in pore pressure and that this particular lake was tapped extremely rapidly.

A big jigsaw puzzle

The scientists are also investigating the landscape around the river, searching for old, dry valleys and small depressions that may explain the drainage system. After driving for just a couple of hours and walking a bit in the forest, they find small valleys which drained into the present course of the river.

The pieces in the jigsaw puzzle are thus gradually falling into place.

“When we fit everything together, we can see the details in and around the enormous lakes which the Russian rivers drained southwards on several occasions and at other times emptied into the Arctic Ocean when the ice melted,” Eiliv Larsen explains.

Researchers find volcanoes helped create life of earth

Mount St. Helens in May 1980, shortly after the eruption of May 18
Mount St. Helens in May 1980, shortly after the eruption of May 18

Geoscientists at The University of Western Australia and Pennsylvania State University have found that the origins of complex life on Earth were significantly affected by volcanic activity more than two billion years ago.

They discovered that the rise of atmospheric oxygen levels, which allowed life to flourish but had long been simply attributed to ancient bacteria, was also due to terrestrial volcanic activity.

The prestigious international journal Nature has published the research paper, “Increased subaerial volcanism and the rise of atmospheric oxygen 2.5 billion years ago”.

The paper is co-authored by Professor Lee Kump, from the NASA Astrobiology Institute and Department of Geosciences at Pennsylvania State University and Professor Mark Barley, from the School of Earth and Geographical Sciences at UWA.

The paper analyses the period covering Earth’s transition from a hostile environment, where poisonous gases absorbed all the oxygen produced by the first photosynthetic organisms, to one in which oxygen levels in the atmosphere and oceans could increase and allow complex life to develop.

“We live in a unique environment. Earth is the only planet we know of that has an oxygen-rich atmosphere, as well as a hydrosphere, and both oceanic and continental crust, which combine to sustain complex life,” Professor Barley said.

The oxygen-producing bacteria believed responsible for the rise in oxygen levels 2.5 billion years ago had been found in rocks 200 million years earlier so scientists had wondered why the bacteria had taken so long to fill the atmosphere with oxygen.

Professor Kump and Professor Barley believe the answer was that underwater volcanoes were undoing the work of the bacteria.

“We believe that the rise of atmospheric oxygen was also closely tied to the Earth’s tectonic evolution,” Professor Barley said.

The researchers analysed published studies of volcanic deposits and found a significant shift from submarine volcanoes to volcanoes on land around the same time that oxygen showed up.

“Volcanic activity produces gases that react with oxygen and remove it from the oceans and atmosphere. Volcanoes that erupt beneath the sea produce more reduced gases than those that erupt on islands or continents and are much more effective at removing oxygen,” Professor Barley said.

As the continents thickened and stabilised, the ocean crust thinned, ocean basins could hold more water and more land bobbed above sea level. As a result, more eruptions took place on solid ground.

The researchers found that unlike underwater volcanoes, terrestrial volcanoes soak up far less oxygen, which explains the time lag between the appearance of bacteria and oxygen’s prominence.

The shift in volcanoes allowed oxygen produced by bacteria to begin accumulating and, two billion years later, to give rise to animals.

Professor Barley said the research showed how finely balanced the Earth’s capacity for sustaining life really was.

“It is important to understand the early evolution of the Earth – we live in a time when global change is a major issue. Human activity is increasing the amount of carbon dioxide in the atmosphere and we need to find ways to lower it, so understanding past changes may help us,” he said.

“History demonstrates that a major event can have huge implications for the planet and events can change things relatively quickly.”