Detections of Directional Dynamic Triggering in Intraplate Regions of the United States

Abstract

ABSTRACT We report tremor or local earthquake signals that occurred during the propagation of Love and Rayleigh waves from the 2012 Mw 8.6 Sumatra earthquake in three intraplate regions: Yellowstone, central Utah, and Raton basin (Colorado). These surface waves likely also dynamically triggered seismic activity along the western boundary of the North American plate, and did not trigger seismic activity in the central and eastern United States. We report additional potential dynamic triggering in the three aforementioned intraplate regions by surface waves from 37 additional large earthquakes, recorded between 2004 and 2017. These surface waves’ transient stresses generally appear to trigger tremor in seismically, volcanically, and hydrothermally active regions, such as Yellowstone, if the waves also arrive from favorable directions. These stresses do not appear to be decisive factors for triggering local earthquakes reported for the Raton basin and central Utah, whereas, surface waves’ incidence angles do appear to be important there.