Reflection imaging of aseismic zones of the Nazca slab by global-phase seismic interferometry

Reflection imaging of aseismic zones of the Nazca slab by global-phase seismic interferometry

Nishitsuji, Y. (TU Delft Applied Geophysics and Petrophysics)
Ruigrok, E (Universiteit Utrecht)
Gomez, M (Comision Nacional de Energia Atomica)
Wapenaar, C.P.A. (TU Delft Applied Geophysics and Petrophysics)
Draganov, D.S. (TU Delft Applied Geophysics and Petrophysics)

2016-05-20

Obtaining detailed images of aseismic parts of subducting slabs remains a large challenge for understanding slab dynamics. Hypocenter mapping cannot be used for the purpose due to the absence of seismicity, whereas the use of receiver functions might be compromised by the presence of melt. Global tomography can be used to identify the presence of the slab, but it does not reveal the structure in detail. We have determined how detailed images can be obtained using global-phase seismic interferometry. The method provides high-resolution (<15km in depth) pseudo zero-offset (i.e., colocated source and receiver) reflection information. We have applied the method to aseismic zones of the Nazca slab in which initiation of possible slab tearing and plume decapitation was identified by global tomography and electrical conductivity, respectively. We have obtained an image of the Moho and the mantle and found an attenuated area in the image consistent with the presence of an aseismic dipping subducting slab. However, our interpretation was not unambiguous. The results confirmed that the method is useful for imaging aseismic transects of slabs.

acoustic
earthquake
illumination
interferometry
interpretation

http://resolver.tudelft.nl/uuid:f940c8ab-a08f-4404-b529-4491af1d6887

https://doi.org/10.1190/INT-2015-0225.1

2324-8858

Interpretation, 4 (3), SJ1-SJ16

Institutional Repository

journal article

© 2016 Y. Nishitsuji, E Ruigrok, M Gomez, C.P.A. Wapenaar, D.S. Draganov