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| Titel |
The 2014 Kefalonia seismic sequence and continuous microseismicity monitoring |
| VerfasserIn |
Vassilios Karakostas, Gerasimos Chouliaras, Eleftheria Papadimitriou, Georgios Drakatos, Maria Mesimeri |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250104458
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| Publikation (Nr.) |
 EGU/EGU2015-3875.pdf |
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| Zusammenfassung |
| On January 26, 2014 a strong (Mw6.1) strike slip earthquake ruptured the western part of
Kefalonia Island, the area with the highest moment rate in the entire Mediterranean, at the
southern part of Palliki peninsula. The sequence continued with numerous aftershocks that in
the first few hours covered an area extended over 35 km, much longer than expected from the
causative fault segment. Intense seismicity encompassing a major aftershock (Mw 5.5) in less
than 6 hours after and several M>4.0 earthquakes mostly during the first three days,
continued along the entire activated area, evidencing a less densely covered part where the
second main shock (Mw6.0) on 3 February occurred, associated with the adjacent fault
segment, located to the north of the firstly failed segment and evidently encouraged by
stress transfer of the first main shock. The aftershock distribution evidenced two
adjacent fault segments striking almost N–S and dipping to the east, in full agreement
with the centroid moment tensor solutions, constituting segments of the Kefalonia
Transform Fault (KTF). Intense aftershock activity lasted for several weeks whereas
continued seismicity afterwards is mainly located off fault with minor and fewer
on fault aftershocks. The seismic network was intensified in the area (Institute of
Geodynamics portable network, seismic stations installed in the frame of OTRIONS
project, CEN–ION network) after the main ruptures, providing improvement both in
detectability and accurate locations. Since network coverage was not previously
adequate for revealing detailed features of the activated area, the improved monitoring
and location is of paramount importance for this scope. More recent seismicity,
forming distinctive clusters, occurred along the edges of the double rupture indicating
activation of adjacent fault segments. To the north several aftershocks forming an
east–northeast striking seismicity band suggest a transfer zone linking KTF with its
northward continuation, the Lefkada Fault. The south cluster, with the larger earthquake
of Mw5.1, reveals again an almost E–W striking fault segment, placed obliquely
to the regional stress field that is characterized by ENE–WSW almost horizontal
compression and NNW–SSE almost horizontal tension. The off fault clusters may
well be interpreted as triggered by stress transfer of the main ruptures, whereas
they shed more light on the regional seismotectonic properties, an indispensable
component for the seismic hazard assessment in this notably high seismicity area. |
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