Rock scratches hint at future quakes

phys.org | 10/2/2018 | Staff
leeann77 (Posted by) Level 3
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Curved scratches in rock faces may give clues to where big quakes could strike next, a study led by Victoria University of Wellington Master's student Jesse Kearse has shown.

These scratches—or 'slickenlines'—have been observed on fault lines for decades. Through his Master's research—published last month in the journal Geology—Jesse was able to link the direction of the slickenlines with the direction a fault line ruptures during an earthquake, providing a record of how past earthquakes have moved on New Zealand's fault lines and hints as to where future earthquake damage could occur.

Jesse - Research - Kekerengu - Fault - Line

Jesse's research began when he was analysing the Kekerengu fault line as part of the Kaikōura Earthquake Surface Rupture Response Team immediately following the Kaikōura earthquake.

"We were mapping the ground ruptures that occurred around the Kekerengu fault as a result of the Kaikōura earthquake, and we found these intriguing curved marks," Jesse says. "We wanted to uncover the process behind their formation, because we knew this was a field of research that wasn't well understood."

Supervisors - Professor - Tim - Little - Victoria

Alongside his supervisors Professor Tim Little of Victoria University of Wellington and Russ van Dissen from GNS Science, Jesse spent many weeks in the field, walking the ground ruptures from end to end—a total distance of 30 kilometres—documenting the ground deformation, and recording the slickenlines.

"After completing these observations, we took our data back to the lab for analysis," Jesse says. "We knew that the rupturing of the Kekerengu fault had caused the ground to shift sideways by up to 12 m during the Kaikoura earthquake. Our analysis of the slickenlines not only confirmed this movement, but also provided further detailed information about how the fault moved—not in a straight line, but along a complicated, curved...
(Excerpt) Read more at: phys.org
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