Splitting Continents and Shaping Earthquakes: New Findings on the Formation of the Seattle Fault Zone

Friday - February 23 2024, 09:39 UTC - 1 year ago

A recent study offers new insights on the formation of the Seattle fault zone, a series of shallow faults that pose a risk of destructive earthquakes to the four million people living in the Puget Sound region. The study suggests that the fault may have originated from the continent's edge splitting in half over 50 million years ago, caused by a chain of volcanic islands pulling towards the continent. Understanding the Seattle fault's behavior and hazards is crucial for protecting the region, as well as other potentially hazardous geological features in the Pacific Northwest.

The Seattle fault zone, a series of shallow faults running across the Puget Sound lowlands in Washington state, is a source of concern for the four million people living in the region due to its potential for causing large, destructive earthquakes. But how did this fault system come to be? A recent study published in Tectonics, a journal of the American Geophysical Union, offers new insights on the formation of the Seattle fault, shedding light on its potential hazards.

The study, led by geophysicist Megan Anderson, looked at the modern topography of the region to understand the underlying structural features of the Seattle fault. By studying the region's past geological events and movements, the team sought to better predict and prepare for future earthquakes.

The study's findings suggest that the Seattle fault may have originated from the continental edge splitting in half over 50 million years ago. This split was caused by a chain of volcanic islands being pulled towards the continent, creating great strain and tearing in the Earth's crust. This ancient tear zone eventually became the foundation for the modern Seattle fault, which has been active due to ongoing tectonic deformation in the region.

Anderson and her team's discovery was unexpected, but holds important implications for understanding the Seattle fault's behavior and hazards. Lindquist, a geologist at the University of Washington, notes that previous studies had identified the Seattle fault as multiple strands based on seismic data, but these strands had never been observed on the surface. However, the new study's approach of focusing on topography has revealed a major ancient fault underneath the modern Seattle fault.

The findings of this study are significant not only for the Seattle region, but for the entire Pacific Northwest, a region that has experienced major geological shifts and destructive earthquakes before. With the potential for future earthquakes looming, it is crucial that we continue to study and monitor the Seattle fault and other hazardous features in the region. Through continued research, we can better prepare and protect our communities from potentially devastating natural disasters.