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Seismic Evidence of an Early Afterslip During the 2012 Sequence in Emilia (Italy)
Author(s) -
Sugan M.,
Vuan A.,
Kato A.,
Massa M.,
Amati G.
Publication year - 2019
Publication title -
geophysical research letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.007
H-Index - 273
eISSN - 1944-8007
pISSN - 0094-8276
DOI - 10.1029/2018gl079617
Subject(s) - geology , seismology , induced seismicity , slip (aerodynamics) , sequence (biology) , physics , genetics , biology , thermodynamics
We apply a matched‐filter‐technique to augment the detected events in the time window between the two mainshocks of the 2012 Emilia seismic sequence (Italy), 20 (M w 6.1) and 29 (M w 6.0) May. Using well‐located templates, we increase the number of detections from 1,727 to 7,616. This greater detail allows evidencing migrations of seismic events from the nucleation point of the first shock to the second. Repeating earthquakes are also found between the two mainshocks. The seismicity pattern suggests a transient slip acting immediately after the shallow first event, weakening and loading the volume around the deep nucleation point of the 29 May M w 6.0 earthquake. We interpret migrations and repeaters as the fingerprint of an early afterslip triggered by the first mainshock. By taking into account the earliest repeater we estimate a cumulative slip of approximately 27 cm (M w 5.7). This value could represent the lower bound of the total released afterslip.