 |
| Titel |
A new model of the upper mantle structure beneath the western rim of the East European Craton |
| VerfasserIn |
M. Dec, M. Malinowski, E. Perchuć |
| Medientyp |
Artikel
|
| Sprache |
Englisch
|
| ISSN |
1869-9510
|
| Digitales Dokument |
URL |
| Erschienen |
In: Solid Earth ; 5, no. 1 ; Nr. 5, no. 1 (2014-06-26), S.523-535 |
| Datensatznummer |
250115285
|
| Publikation (Nr.) |
 copernicus.org/se-5-523-2014.pdf |
|
|
|
|
|
| Zusammenfassung |
| We present a new 1-D P wave seismic velocity model (called MP1-SUW) of the
upper mantle structure beneath the western rim of the East European Craton
(EEC) based on the analysis of the earthquakes recorded at the Suwałki
(SUW) seismic station located in NE Poland which belongs to the Polish
Seismological Network (PLSN). Motivation for this study arises from the
observation of a group of reflected waves after expected P410P at
epicentral distances 2300–2800 km from the SUW station. Although the
existing global models represent the first-arrival traveltimes, they do not
represent the full wavefield with all reflected waves because they do not
take into account the structural features occurring regionally such as
300 km discontinuity. We perform P wave traveltime analysis using 1-D and 2-D
forward ray-tracing modelling for the distances of up to 3000 km. We
analysed
249 natural seismic events from four azimuthal spans with epicentres in the
western Mediterranean Sea region (WMSR), the Greece and Turkey region (GTR),
the Caucasus region (CR) and the part of the northern Mid-Atlantic Ridge near the
Jan Mayen Island (JMR). For all chosen regions, except the JMR group for
which 2-D modelling was performed, we estimate a 1-D average velocity model
which will characterize the main seismic discontinuities. It appears that a
single 1-D model (MP1-SUW model) explains well the observed traveltimes for
the analysed groups of events. Differences resulting from the different
azimuth range of earthquakes are close to the assumed picking uncertainty.
The MP1-SUW model documents the bottom of the asthenospheric low-velocity zone
(LVZ) at the depth of 220 km, 335 km discontinuity and the zone with the
reduction of P wave velocity atop 410 km discontinuity which is depressed to
440 km depth. The nature of the regionally occurring 300 km boundary is
explained here by tracing the ancient subduction regime related to the
closure of the Iapetus Ocean, the Rheic Ocean and the Tornquist Sea. |
| |
|
| Teil von |
|
|
|
|
|
|
|
|