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| Titel |
Rupture plane identification of intermediate depth earthquakes in the Hellenic arc by back projection of local seismic waveforms |
| VerfasserIn |
C. P. Evangelidis, H. Kao |
| Konferenz |
EGU General Assembly 2012
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 14 (2012) |
| Datensatznummer |
250069176
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| Zusammenfassung |
| We apply the Source-Scanning Algorithm (SSA), an earthquake back projection approach, to
identify the rupture plane and possible source time function asperities of intermediate depth
earthquakes in the Hellenic arc. We use P-waveform envelopes from recordings on local
broadband stations at epicentral distances as much as 200Â km. At each grid point of a
predefined source volume we sum the normalized observed amplitudes at the corresponding
predicted arrival times for each station with an appropriate time correction. The produced
composite brightness image in both space and time resembles the earthquake rupture plane,
and the source asperities. Intermediate depth earthquakes are the ideal candidates for
this type of analysis, since the P-wave train is well defined and separated from
secondary phases. Moreover, the small number of aftershocks can not define with
certainty the true rupture plane, that constrain the predominant stress field and the
mechanisms that produces them. Initially, we apply the method to the Mw 6.2 Leonidio
earthquake (2008) to identify the known low dipping rupture plane, imaging at
least three different source asperities. The earthquake’s maximum brightness in
time, that resembles the centroid, is distinctively separated from the origin time.
Consequently, the method is applied to two moderate (Mw 6.0-6.5) intermediate
depth earthquakes at the southeastern end of the Hellenic arc that have not been
studied before in order to image the spatiotemporal distribution of asperities and
identify the fault planes. Finally, the application of this back projection approach
to events recorded on a local network gives evidence on its spatial and temporal
resolution. |
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