2025/11/18 by Emily A. Morton, Keith D. Koper, D. Kilb +1 · 1 voice
Computer Science · Earth and Planetary Sciences · #Seismic Waves and Analysis #Seismology and Earthquake Studies #earthquake and tectonic studies
paper · doi:10.1785/0120250155
openalex created_date 2025/11/18 · openalex publication_date 2025/11/18 · openalex updated_date 2026/07/31
ABSTRACT In terms of annualized earthquake loss and casualties, Utah has the fourth-highest seismic risk among U.S. states, after California, Washington, and Oregon. Seismic hazard is highest in the urban corridor along the Wasatch fault zone, which has hosted ≥24 surface-rupturing earthquakes (M 6.75+) in the last 6500 yr. Motivated by the 2021 rollout of ShakeAlert along the U.S. West Coast—and the increasing popularity of earthquake early warning (EEW) systems worldwide—the Utah legislature commissioned a study on the feasibility of implementing EEW in the state. Here, we expand on the seismology component of that report, focusing on the required instrumentation upgrades to the existing network, the idealized warning times expected for six representative earthquake scenarios, and the frequency with which alerts would be issued. We investigate a regional EEW system, relying on the requirements of the existing West Coast ShakeAlert system. If the existing Utah seismograph stations were upgraded with low-latency recorders and improved telemetry, we find that a prototype EEW system could currently be operated along the Wasatch fault zone. Installation of 64 additional stations is required for EEW to be fully operational throughout the Wasatch Front, and another 117 stations for EEW to fully operate throughout the Utah Intermountain Seismic Belt. Areas expected to have damaging ground shaking (modified Mercalli intensity [MMI] ≥ 5.5) in the six earthquake scenarios would receive 0–10 s of warning to prepare for shaking, whereas areas expected to have noticeable ground shaking but little-to-no damage (MMI 1–5.5) would receive 10–55 s of warning. A fully operational Wasatch Front EEW system set to alert on M 4.5+ earthquakes, like the West Coast ShakeAlert system, would be expected to activate once every four years on average, although the alerts would strongly cluster in time, reflecting the natural patterns of earthquake activity.