PROVIDENCE, R.I. [Brown University] - The Earth's lithosphere, which is made up of rigid plates, often forms visible boundaries on the planet's surface known as faults when they brush against each other. These boundaries, such as the San Andreas Fault in California or the Denali Fault in Alaska, are capable of producing powerful seismic activity. A new research led by Brown University seismologists is providing insight into how these faults form and behave as they deepen. The scientists used cutting-edge data from a network of seismic stations to create a new 3D model of seismic wave velocities throughout Alaska, and found that changes in the thickness and internal strength of the tectonic plate that Alaska sits on play a key role in the location of Alaska's Denali Fault.

The Denali Fault is a 1,200-mile-long fault that arcs across most of Alaska and some of Western Canada. In 2002, it was the site of a magnitude 7.9 earthquake that caused seismic waves to reach as far as Seattle, Texas, and New Orleans. This new research provides insight into how the strength of the deeper rocks in the tectonic plate affects the dynamics of the Denali Fault and can help in understanding the stress build-up on the fault and the likelihood of future ruptures.

A geological time bomb ticking beneath the Alaskan wilderness, the Denali Fault, could have disastrous repercussions for Seattle, a city over 2,000 miles away. The 2002 magnitude 7.9 earthquake that shook the fault sent seismic ripples as far as Seattle, and any future major tremor on the Denali Fault could spell disaster for the city. But thanks to new research delving deeper into the Earth's crust, scientists are now able to shed light on the inner workings of the Denali Fault and develop better earthquake models to predict and mitigate the hazards it poses to Seattle and other nearby areas.

The study, published in Geophysical Research Letters, was led by Brown alumna Isabella Gama, who completed the work last year while she was a Ph.D. student in the University’s Department of Earth, Environmental and Planetary Sciences. The research begins to fill major gaps in understanding about how geological faults behave and appear as they deepen, and they could eventually help lead future researchers to develop better earthquake models on strike-slip faults, regions with frequent and major earthquakes.