Exploring Sedimentary Basins with High Frequency Receiver Function: the Dublin Basin Case Study

Autor(en)

A. Licciardi, N. Piana Agostinetti

Abstrakt

The Receiver Function (RF) method is a widely applied seismological tool

for the imaging of crustal and lithospheric structures beneath a single

seismic station with one to tens kilometers of vertical resolution.

However, detailed information about the upper crust (0-10 km depth) can

also be retrieved by increasing the frequency content of the analyzed RF

data-set (with a vertical resolution lower than 0.5km). This information

includes depth of velocity contrasts, S-wave velocities within layers,

as well as presence and location of seismic anisotropy or dipping

interfaces (e.g., induced by faulting) at depth. These observables

provides valuable constraints on the structural settings and properties

of sedimentary basins both for scientific and industrial applications.

To test the RF capabilities for this high resolution application, six

broadband seismic stations have been deployed across the southwestern

margin of the Dublin Basin (DB), Ireland, whose geothermal potential has

been investigated in the last few years. With an inter-station distance

of about 1km, this closely spaced array has been designed to provide a

clear picture of the structural transition between the margin and the

inner portion of the basin. In this study, a Bayesian approach is used

to retrieve the posterior probability distributions of S-wave velocity

at depth beneath each seismic station. A multi-frequency RF data-set is

analyzed and RF and curves of apparent velocity are jointly inverted to

better constrain absolute velocity variations. A pseudo 2D section is

built to observe the lateral changes in elastic properties across the

margin of the basin with a focus in the shallow portion of the crust.

Moreover, by means of the harmonic decomposition technique, the

azimuthal variations in the RF data-set are isolated and interpreted in

terms of anisotropy and dipping interfaces associated with the major

fault system in the area. These results are compared with the available

information from previous seismic active surveys in the area, including

boreholes data.

Organisation(en)

Externe Organisation(en)

Dublin Institute for Advanced Studies

Publikationsdatum

12-2015

Peer-reviewed

Ja

ÖFOS 2012

105102 Allgemeine Geophysik

Schlagwörter

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