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Anomalous aftershocks of deep earthquakes in Mariana
Author(s) -
Wu LiRu,
Chen WangPing
Publication year - 1999
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 - 10.1029/1999gl900389
Subject(s) - aftershock , seismology , geology , seismic moment , deep focus earthquake , subduction , fault (geology) , tectonics
Seismic moment of aftershocks during the August 23, 1995 deep earthquake sequence in the Mariana amounts up to 17% of that of the main shock ( M w 7.0). Such a high aftershock activity is extremely unusual. Based on the inversion of broadband P and SH waveforms, however, we found nothing anomalous in the source mechanisms. Among the 33 largest deep earthquakes ( M w ≥7.0) since 1958, only events in the Mariana have high aftershock activity. We associate this observation with the unique configuration of the Mariana slab which seems to plunge sub‐vertically into the lower mantle with little distortion.