Missouri University of Science and Technology is at the cutting edge of earthquake prediction. Researchers at Missouri S&T recognize the growing importance of predicting earthquakes especially following the large magnitude earthquakes which struck southern California over the summer of 2019. These earthquakes were some of the largest in California history one ranking as a 6.4 magnitude and another as a 7.1 magnitude. Both of these earthquakes had the potential to be detrimental. It is for this reason that researchers are so keen on finding ways to predict earthquake activity such that an adequate warning may be given for people to seek shelter.
Dr. Kelly Liu, a professor in Missouri S&T’s geosciences and geological and petroleum engineering department, is studying past seismic activity, specifically shear wave splitting, to solve this problem. Since an earthquake cannot be seen besides its effects, “indirect tools, such as relying on computer analyses of a large amount of geophysical data collected at the earth’s surface, are essential for accurate and useful predictions,” says Dr. Liu. Shear wave splitting is the phenomenon which occurs when a polarized shear wave, generated through the movement of tectonic plates, splits into two waves as a result of traveling through medium whose properties vary depending on direction. Shear wave splitting can help to provide an image of the Earth's underlying deformation and mantle flow orientation in an area. Shear wave data from the year 1980 to the present date is the main focus of Dr. Liu's research.
Dr. Liu informs that “Shear wave splitting analysis is one of the most effective tools to investigate plate motion. But in spite of years-worth of studies, some fundamental issues related to how natural hazards such as earthquakes can occur on the earth are still poorly understood. `` A likely reason that previous studies were unsuccessful is that the areas of study have been assumed to contain a single layer of anisotropy. According to Dr. Liu, this is not an accurate assumption. In reality the Earth is more complicated and the addition of seismic stations for research projects such as this one and the number of earthquakes which are being recorded as a result are proving this. “The identification of multiple layers of seismic anisotropy can significantly improve our understanding of the engine of the deformation that is directly related to the occurrence of natural hazards,” says Dr. Liu. She believes “this project will develop and test a set of sophisticated tools to systematically investigate complex anisotropy on a global scale, for the purpose of providing constraints on a number of hypotheses related to plate dynamics and plate motion.”
Dr. Liu is working alongside Dr. Stephen Gao who holds the title of Curators’ Distinguished Teaching Professor of geology and geophysics at Missouri S&T. Their research is funded by the National Science Foundation Geophysics Program and is titled “Investigating the Pervasiveness of Complex Seismic Anisotropy and Its Origin beneath Continents.”
The overarching goal is not only to understand earthquakes and the subsurface conditions which cause them, but to implement this knowledge such that a warning system may be created to protect people from earthquakes and give them time to prepare before an earthquake hits.
*Photo credit to Mario Tama. Image of man examining damage caused by magnitude 7.1 earthquake.