High-precision earthquake catalog for Minto Flats fault zone, central Alaska, reveals complex and conjugate faulting

Bulletin of Seismological Society of America
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Abstract

The Minto Flats fault zone (MFFZ) in central Alaska is a left‐lateral strike‐slip fault system situated between the continental‐scale right‐lateral Denali and Kaltag‐Tintina faults. The MFFZ has the potential to generate magnitude 7 earthquakes, and it hosted a magnitude 6 earthquake in 1995. It has also produced exotic events, such as very‐low‐frequency earthquakes and nucleation signals. We use network‐matched filtering and relative earthquake relocation techniques to derive a detailed catalog of earthquake locations for the MFFZ. The catalog spans from August 2014 to December 2019, a time period including 13 temporary seismic stations in the region. Our results provide the most complete catalog for the MFFZ and include deeper events, clusters of shallow seismicity, and a complex and segmented fault structure not observed in the original regional catalog. We document right‐lateral strike‐slip faulting, conjugate to the main northeast‐striking left‐lateral faults of the MFFZ. Below Nenana basin, the relocated seismicity reveals northwest‐dipping left‐lateral faults, supporting the inference that deep crustal active faulting is associated with recent basin deformation.

Suggested Citation

Sims, N.E., Tape, C., Ruppert, N., West, M.E., 2026, High-precision earthquake catalog for Minto Flats fault zone, central Alaska, reveals complex and conjugate faulting: Bulletin of Seismological Society of America, v. 116, no. 1, p. 375-396, https://doi.org/10.1785/0120250177.

Study Area

Publication type Article
Publication Subtype Journal Article
Title High-precision earthquake catalog for Minto Flats fault zone, central Alaska, reveals complex and conjugate faulting
Series title Bulletin of Seismological Society of America
DOI 10.1785/0120250177
Volume 116
Issue 1
Publication Date November 04, 2025
Year Published 2026
Language English
Publisher Seismological Society of America
Contributing office(s) Earthquake Science Center
Description 22 p.
First page 375
Last page 396
Country United States
State Alaska
Other Geospatial Minto Flats fault zone
Additional publication details