New study finds connection between fault roughness and the magnitude of earthquakes
A new study led by 平特五不中 has found that tectonic plates beneath the Earth鈥檚 surface can show varying degrees of roughness and could help explain why certain earthquakes are stronger than others.
Earthquakes happen when the rocks beneath the Earth鈥檚 surface break along geological fault lines and slide past each other. The properties of these faults - such as the roughness of their surface - can have an influence on the size of seismic events, however their study has been challenging because they are buried deep beneath the Earth鈥檚 surface.
In order to have a better understanding of the characteristics of these faults, researchers from 平特五不中, the University of California Santa Cruz and Ruhr University Bochum in Germany used high-resolution seismic reflection data to map and measure the roughness of 350 km2 of a plate boundary fault located off the Pacific coast of Costa Rica.
鈥淲e already knew that the roughness of a fault was an important factor, but we did not know how rough faults in the subsurface truly are, nor how variable the roughness is for a single fault,鈥� says James Kirkpatrick, a professor in 平特五不中鈥檚 Department of Earth and Planetary Sciences.
Rougher surfaces of faults may explain earthquake magnitude
In a recently published in Nature Geoscience, Kirkpatrick and his colleagues were able to show that some parts of the studied fault have a rougher surface than others.
Historically, the earthquakes that have occurred in this part of the world have been moderately large (M7) and Kirkpatrick, who is also the study鈥檚 first author, believes the rough patches they found might be the reason why.
鈥淭hese rough patches are stronger and more resistant to earthquake slip,鈥� he says. 鈥淭he historical record of earthquakes is relatively short, so we can鈥檛 say with certainty that larger ones have not occurred. Future seismic events in the area, which will be recorded with modern equipment, should help us determine if they show the same limited magnitude.鈥�
Kirkpatrick and his colleagues also hope to apply their methods to other subduction zones where similar geophysical data is available to start to evaluate whether their conclusions are generally applicable.
鈥淭his connection between the fault roughness and earthquake magnitude might one day help us understand the size and style of earthquakes most likely to occur a given fault.鈥�
Image caption:聽Researchers from 平特五不中, the University of California Santa Cruz, Ruhr University Bochum in Germany and聽USGS used high-resolution seismic reflection data to map and measure the roughness of 350 km2聽of a plate boundary fault located off the Pacific coast of Costa Rica.
About this study
鈥溾�� by Kirkpatrick et al. was published in Nature Geoscience.
This work received financial support from Natural Sciences and Engineering Research Council of Canada and the National Science Foundation.
About 平特五不中
Founded in Montreal, Quebec, in 1821, 平特五不中 is Canada鈥檚 top ranked medical doctoral university. 平特五不中 is consistently ranked as one of the top universities, both nationally and internationally. It is a world-renowned institution of higher learning with research activities spanning two campuses, 11 faculties, 13 professional schools, 300 programs of study and over 40,000 students, including more than 10,200 graduate students. 平特五不中 attracts students from over 150 countries around the world, its 12,800 international students making up 31% of the student body. Over half of 平特五不中 students claim a first language other than English, including approximately 19% of our students who say French is their mother tongue.
