| dc.creator |
Çakir, Özcan |
|
| dc.creator |
Erduran, Murat |
|
| dc.date |
2004-09-01T00:00:00Z |
|
| dc.date.accessioned |
2025-02-25T10:37:02Z |
|
| dc.date.available |
2025-02-25T10:37:02Z |
|
| dc.identifier |
b805a3ed-e657-44df-a287-bb54d8b4d662 |
|
| dc.identifier |
10.1111/j.1365-246x.2004.02345.x |
|
| dc.identifier |
https://avesis.sdu.edu.tr/publication/details/b805a3ed-e657-44df-a287-bb54d8b4d662/oai |
|
| dc.identifier.uri |
http://acikerisim.sdu.edu.tr/xmlui/handle/123456789/101109 |
|
| dc.description |
We jointly invert teleseismic radial-component receiver functions and regional Rayleigh and Love surface-wave group velocities for 1-D shear-wave velocity structure beneath station TBZ located on the northern side of the eastern Pontides. An influence factor is employed to control the relative influence of receiver function and surface-wave dispersion on the resultant velocity-depth profile. Radial- and transverse-component receiver functions at station TBZ exhibit an azimuthal amplitude and polarity pattern consistent with 2-D receiver structure that has a general dip direction towards approximately south. The radial-component receiver functions are least affected by the dipping structures along the strike direction and thereby we prefer teleseismic events sampling along-strike structures to alleviate the deflecting effect of dipping interfaces on the 1-D solution. The 1-D inversion effectively reveals the two-layer nature of the crust which is perturbed by high- and low-velocity layers, and serves as a provisional model for the 2-D forward modelling. Minor-to-moderate changes to the 1-D model, such as changing depth to and velocity contrast across an interface, are needed to achieve the results with the 2-D modelling. Dipping interfaces and seismic anisotropy are included in the 2-D modelling to fit both radial- and transverse-component receiver functions. The upper crust is characterized by a shear velocity of ∼3.5 km s-1 and cut through by a 4 km thick high-velocity (i.e. ∼3.8 km s-1) layer. Overlying the upper crust, the sedimentary cover (i.e. the top 5 km) has velocities within the range ∼2.0-3.5 kms-1. A mid-crustal velocity discontinuity between the upper granitic crust and the lower basaltic crust is identified at ∼16-km depth. This boundary is analogous to the mid-crustal discontinuity found under the Black Sea basin across which the shear velocity jumps from 3.5 to 4.1 km s-1. A relatively thick (i.e. ∼12 km) low-velocity layer in the lower crust with a velocity reversal from 4.1 to 3.7 km s-1 is needed to better explain reverberations off this depth range. We infer a 2-D Moho discontinuity placed at ∼35-km depth beneath the station. The proposed dip angle for the Moho is rather steep (i.e. ∼25°), although coincident with regional gravity studies. The associated Sn velocity (i.e. ∼4.4 km s-1) is rather low, indicating disturbed upper-mantle structure beneath the region. Initial amplitudes of transverse-component receiver functions are rather energetic, for which we propose substantial P and S velocity anisotropy (∼12 per cent) for the topmost depths (<5 km). |
|
| dc.language |
eng |
|
| dc.rights |
info:eu-repo/semantics/closedAccess |
|
| dc.title |
Constraining crustal and uppermost mantle structure beneath station TBZ (Trabzon, Turkey) by receiver function and dispersion analyses |
|
| dc.type |
info:eu-repo/semantics/article |
|