Phantom earthquakes and triggered aseismic creep: Vertical partitioning of strain during earthquake sequences in Iran
Article first published online: 14 MAR 2013
©2013. American Geophysical Union. All Rights Reserved.
Geophysical Research Letters
Volume 40, Issue 5, pages 819–823, 16 March 2013
How to Cite
2013), Vertical partitioning of strain during earthquake sequences in Iran: Phantom earthquakes and triggered aseismic creep, Geophys. Res. Lett., 40, 819–823, doi:10.1002/grl.50201., and (
- Issue published online: 24 APR 2013
- Article first published online: 14 MAR 2013
- Accepted manuscript online: 15 FEB 2013 01:32PM EST
- Manuscript Accepted: 27 JAN 2013
- Manuscript Revised: 23 JAN 2013
- Manuscript Received: 30 NOV 2012
- Aseismic slip;
 We present evidence for significant aseismic fault slip at shallow depth above a pair of mainshock-aftershock sequences in the Zagros Mountains of Iran. The two Mw 5.9 earthquakes are each spanned by high-quality geodetic imagery and have well-recorded sequences of aftershocks that occurred beneath a salt décollement. Earlier studies of the geodetic data inferred that the mainshocks were located above the décollement, requiring a ~10 km spatial separation between aftershock cluster and earthquake centroid. We find that the geodetic data simultaneously allow two slip sources of similar magnitude: one within the basement, collocated with aftershocks, and one shallow source (also equivalent to Mw 6) responsible for the primary signal apparent in the geodetic imagery. Should this phenomenon be widespread in the Zagros, it would partially explain a previously noted discrepancy between observed seismic moment release in the Zagros and current convergence rates between the Arabian and Eurasian plates.