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| Titel |
Imaging of urban sinkhole structures - combination of P-wave and shear-wave reflection seismic profiling in the metropolitan region of Hamburg |
| VerfasserIn |
C. M. Krawczyk, U. Polom, T. Dahm |
| 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 |
250061147
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| Zusammenfassung |
| The investigated roof region of a salt diapir in Hamburg, northern Germany, suffers sinkhole activity that was accompanied lately by microseismic events in the Gross Flottbek quarter. Thus, a high geohazard potential is present which can only be evaluated if highly resolved structural data are available.
In addition to a shear-wave reflection seismic survey we performed with our shear-wave seismic system (ELVIS microvibrator, 120 m land streamer with 1 m SH-geophone distance), we also measured two P-wave reflection seismic profiles with the aim of imaging the top of the salt diapir. The LIAG- minivibrator and planted geophones of 5 m distance were used. The main profile runs along the major shear-wave line, the other crosses perpendicularly, so that a good areal coverage is given.
Top salt is suggested at ca. 180 m depth, which is slightly deeper than previously thought from gravimetric measurements and larger-scale modelling. However, the general dip of the salt flank is further corroborated by additional gravimetric measurements. The surface of the salt dome undulates in the 10 m-range. Variable continuity of reflective elements and amplitude further characterize the top salt surface, which will be discussed in the context of fault and subrosion structures revealed from the shear-wave seismic experiment. |
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