Publication Date:
2014-07-19
Description:
To obtain a precise record of the foreshock sequence before the 2014 Iquique, Chile Mw 8.1 earthquake, we applied a matched-filter technique to continuous seismograms recorded near the source region. We newly detected about 10 times the number of seismic events listed in the routinely constructed earthquake catalog, and identified multiple sequences of earthquake migrations at speeds of 2–10 km/day, both along-strike and down-dip on the fault plane, up-dip of the mainshock area. In addition, we found out repeating earthquakes from the newly detected events, likely indicating aseismic slip along the plate boundary fault during the foreshock sequence. These observations suggest the occurrence of multiple slow-slip events up-dip of the mainshock area. The final slow-slip event migrated toward the mainshock nucleation point. We interpret that several parts of the plate boundary fault perhaps experienced slow slip, causing stress loading on the prospective largest slip patch of the mainshock rupture.
Print ISSN:
0094-8276
Electronic ISSN:
1944-8007
Topics:
Geosciences
,
Physics
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