Permanently enhanced dynamic triggering probabilities as evidenced by two M ≥ 7.5 earthquakes
Article first published online: 18 SEP 2013
This paper is not subject to U.S. copyright. Published in 2013 by the American Geophysical Union.
Geophysical Research Letters
Volume 40, Issue 18, pages 4828–4833, 28 September 2013
How to Cite
2013), Permanently enhanced dynamic triggering probabilities as evidenced by two M ≥ 7.5 earthquakes, Geophys. Res. Lett., 40, 4828–4833, doi:10.1002/grl.50933.(
- Issue published online: 11 OCT 2013
- Article first published online: 18 SEP 2013
- Accepted manuscript online: 9 SEP 2013 04:42PM EST
- Manuscript Accepted: 6 SEP 2013
- Manuscript Revised: 1 SEP 2013
- Manuscript Received: 1 AUG 2013
- dynamic triggering;
- Queen Charlotte Fault;
 The 2012 M7.7 Haida Gwaii earthquake radiated waves that likely dynamically triggered the 2013 M7.5 Craig earthquake, setting two precedents. First, the triggered earthquake is the largest dynamically triggered shear failure event documented to date. Second, the events highlight a connection between geologic structure, sedimentary troughs that act as waveguides, and triggering probability. The Haida Gwaii earthquake excited extraordinarily large waves within and beyond the Queen Charlotte Trough, which propagated well into mainland Alaska and likely triggering the Craig earthquake along the way. Previously, focusing and associated dynamic triggering have been attributed to unpredictable source effects. This case suggests that elevated dynamic triggering probabilities may exist along the many structures where sedimentary troughs overlie major faults, such as subduction zones’ accretionary prisms and transform faults’ axial valleys. Although data are sparse, I find no evidence of accelerating seismic activity in the vicinity of the Craig rupture between it and the Haida Gwaii earthquake.