Seismologists Map Sharp Linear Cluster of Earthquakes Along Subducted Yakutat Slab in Alaska
A study using machine-learning techniques identified a 250-km linear series of small earthquakes that trace the edge of the subducted Yakutat microplate beneath central Alaska, shedding light on the region’s tectonic stress and the 2002 Denali quake.
A team of seismologists has identified a narrow, 250-kilometre line of earthquakes that delineates the edge of the subducted Yakutat slab beneath central Alaska. The researchers applied machine-learning methods to seismic data from stations near the Denali Fault and the Alaska Range suture zone, creating a detailed catalog of previously undetected small quakes.
The linear cluster, described by the authors as a "razor-sharp edge," runs northwest to southeast and lies directly beneath the curved section of the Denali Fault. Lead author Meghan Miller of the Australian National University said the machine-learning approach was crucial for revealing patterns that traditional analysis had missed.
"Thousands of small, previously undetected earthquakes form a prominent linear cluster that illuminates the precise edge of the subducted Yakutat microplate and defines the location of changing slab morphology reflecting the change in stress state," the study states.
By analysing seismic noise between events, the team mapped the slab’s extent farther beneath the North American plate than previously recognized, including under the Denali fault. The authors suggest that this configuration contributed to the nucleation of the magnitude-7.9 Denali earthquake in 2002.
The findings also support the idea that the Yakutat slab influences the development of young volcanic fields in south-central Alaska, indicating a re-established mantle wedge over the past million years. The research was published in The Seismic Record.
